JP2008145183A - Measurement device, multipath determination method, and measurement method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve measurement accuracies of a position or the like by accurately determining whether a received GPS signal is multipath. <P>SOLUTION: A receiving device 111 receives a GPS signal (electric wave) (S11). A pseudo-distance measurement section 112 calculates a pseudo distance based on the GPS signal, and a pseudo-distance difference calculation section 113 calculates variation (pseudo-distance difference) of the pseudo distance (S12-S14). A phase distance difference measurement section 114 calculates variation (phase distance difference) of phase distance based on the GPS signal (S15-S16). A multipath determination section 115 compares the pseudo-distance difference with the phase distance difference, and determines whether the GPS signal received by the receiving device 111 is multipath (S17). A position calculation section 130 rejects the pseudo distance determined to be multipath by the multipath determination section 115, and calculates the current position based on the other pseudo distances (S18). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a measuring apparatus and a measuring method for measuring using received radio waves. In particular, the present invention relates to a measuring apparatus and a measuring method for determining whether or not a received radio wave is multipath.

By receiving radio waves such as GPS signals transmitted by GPS (Global Positioning System) satellites, distance measuring devices that measure the distance to GPS satellites, etc., and the current position based on the measured distance In a measuring device such as a positioning device to be calculated, accurate measurement cannot be performed when the received radio wave is a multipath such as a reflected wave.
For this reason, various methods for determining whether or not the received radio wave is multipath have been proposed.
JP-A-2005-207815 JP 2003-279635 A JP 2003-57327 A JP-A-2005-37241 JP 2004-279183 A

  An object of the measurement apparatus according to the present invention is to accurately determine whether or not a received radio wave is multipath, and to obtain a measurement apparatus with high measurement accuracy by eliminating the influence of disturbance due to multipath. To do.

The measuring device according to the present invention is
A processing device for processing information;
A receiving device for receiving radio waves transmitted by the transmitting device;
Pseudo distance that measures the arrival delay time of the radio wave received by the receiving device, calculates the distance to the transmitting device based on the measured arrival delay time, and outputs information indicating the calculated distance as pseudo distance information A measurement unit;
Using the processing device, the pseudo distance information output by the pseudo distance measuring unit is input, and using the processing device, the change amount of the distance to the transmitting device is calculated based on the input pseudo distance information. A pseudo distance difference calculation unit that outputs information indicating the calculated amount of change in the distance as pseudo distance difference information using the processing device;
The amount of change in the phase of the radio wave received by the receiving device is measured, the amount of change in the distance to the transmitting device is calculated based on the amount of change in the measured phase, and information indicating the amount of change in the calculated distance is obtained. A phase distance difference measurement unit that outputs as phase distance difference information;
Using the processing device, the pseudo distance difference information output from the pseudo distance difference calculation unit and the phase distance difference information output from the phase distance difference calculation unit are input, and the pseudo value input using the processing device is input. A multipath determination that compares the distance change amount indicated by the distance difference information with the distance change amount indicated by the input phase distance difference information to determine whether or not the radio wave received by the receiving device is multipath. And
It is characterized by having.

  According to the measurement device of the present invention, the multipath determination unit compares the distance change amount indicated by the pseudo-range difference information with the distance change amount indicated by the phase distance difference information, and receives the radio wave received by the reception device. Since it is determined whether or not is multipath, there is an effect that it is possible to accurately determine whether or not it is multipath.

Embodiment 1 FIG.
The first embodiment will be described with reference to FIGS.

FIG. 1 is a system configuration diagram showing an example of the overall configuration of a positioning system 800 in this embodiment.
The positioning system 800 is an example of a measurement system.
The positioning system 800 includes the positioning terminal device 100 and a plurality of GPS satellites 200.

The GPS satellite 200 is an example of a transmission device.
The GPS satellite 200 transmits a GPS signal.

The positioning terminal device 100 is an example of a measuring device.
The positioning terminal device 100 receives a GPS signal transmitted from the GPS satellite 200, and obtains a distance from each GPS satellite 200 based on the received GPS signal. Since the GPS signal includes information indicating the position of each GPS satellite 200, the positioning terminal apparatus 100 can obtain the current position of the positioning terminal apparatus 100 from the distance to each GPS satellite 200. .

  FIG. 2 is a block configuration diagram illustrating an example of a block configuration of the positioning terminal device 100 according to this embodiment.

  The positioning terminal device 100 includes a CPU 911, a storage device 920, a display device 901, a receiving device 111, a pseudo distance measurement unit 112, a pseudo distance difference calculation unit 113, a phase distance difference measurement unit 114, a multipath determination unit 115, and an angular velocity measurement unit 121. A speed measuring unit 122 and a position calculating unit 130.

A CPU 911 (Central Processing Unit) is an example of a processing device.
The CPU 911 is a device that processes information by executing a program stored in the storage device 920 and realizes the function of each block described below. In the following description, processing of a block that does not explicitly indicate use of the CPU 911 may be performed using the CPU 911. Conversely, processing of a block that clearly indicates the use of the CPU 911 may be performed by a dedicated circuit or the like.

The storage device 920 stores information. The storage device 920 is, for example, a volatile memory such as a RAM (Random Access Memory), a nonvolatile memory such as a ROM (Read Only Memory), or an external storage device such as a magnetic disk device.
The storage device 920 stores a program executed by the CPU 911, for example. In addition, the storage device 920 stores information to be processed by the CPU 911, information indicating a result of processing by the CPU 911, and the like.

The display device 901 displays information. The display device 901 is, for example, an LCD (Liquid Crystal Display).
The display device 901 displays information processed by the CPU 911 and the like (for example, the current position of the positioning terminal device 100) to notify the user.

  The receiving device 111 receives a GPS signal (radio wave) transmitted from the GPS satellite 200.

The pseudo distance measuring unit 112 measures the arrival delay time of the GPS signal received by the receiving device 111.
Since the GPS signal includes information indicating the time at which the GPS satellite 200 transmits the GPS signal, the pseudo distance measuring unit 112 measures the time at which the receiving device 111 receives the GPS signal, and the GPS signal arrives. Find the delay time.
The pseudo distance measuring unit 112 calculates the distance to the GPS satellite 200 based on the measured arrival delay time. Since the GPS signal propagates at the speed of light, the pseudo distance measuring unit 112 calculates the distance to the GPS satellite 200 by multiplying the arrival delay time by the speed of light. Since the GPS signal includes information indicating the ionospheric state and the like, the pseudo distance measuring unit 112 calculates a distance in which the delay based on the ionospheric state and the like is corrected.
The distance to the GPS satellite 200 calculated in this way is called a pseudo distance.
The pseudo distance measuring unit 112 outputs information indicating the calculated pseudo distance as pseudo distance information.
The pseudo distance measuring unit 112 repeatedly calculates the pseudo distance at a predetermined period, and repeatedly outputs the pseudo distance information. The pseudo distance measuring unit 112 calculates the pseudo distance, for example, at intervals of 4 times per second (once every 250 milliseconds).

The pseudo distance difference calculation unit 113 uses the CPU 911 to input the pseudo distance information output from the pseudo distance measurement unit 112.
The pseudo distance difference calculation unit 113 uses the storage device 920 to store the input pseudo distance information. The pseudo distance difference calculation unit 113 stores at least the latest pseudo distance information and the previous pseudo distance information among the pseudo distance information repeatedly output by the pseudo distance measurement unit 112.
The pseudo distance difference calculation unit 113 uses the CPU 911 to calculate the change amount of the pseudo distance based on the input pseudo distance information. For example, the pseudo distance difference calculation unit 113 subtracts the previous pseudo distance from the latest pseudo distance, obtains the pseudo distance difference, and sets the pseudo distance difference.
The pseudo distance difference calculation unit 113 outputs information indicating the calculated pseudo distance change amount as pseudo distance difference information using a processing device such as the CPU 911.

The phase distance difference measuring unit 114 measures the amount of change in the phase of the GPS signal received by the receiving device 111.
For example, the phase distance difference measuring unit 114 measures the phase of the GPS signal at a predetermined period, and calculates the difference from the previously measured phase. The interval for measuring the phase of the GPS signal is, for example, once every 50 milliseconds. The phase distance difference measuring unit 114 calculates the amount of phase change by summing the calculated phase differences within a predetermined period. The predetermined period is equal to a period from the time when the pseudo distance measuring unit 112 previously measured the pseudo distance to the time measured this time, for example, 250 milliseconds. The phase distance difference measuring unit 114 adds up the phase differences calculated during this period (for example, five) to obtain the amount of phase change.

Note that the phase distance difference measurement unit 114 only needs to obtain the amount of change in phase from the time when the pseudo distance measurement unit 112 measures the pseudo distance to the next time when the pseudo distance is measured. Therefore, the phase distance difference measurement unit 114 needs to measure the phase at least at the same time as the pseudo distance measurement unit 112 measures the pseudo distance. The interval at which the phase distance difference measurement unit 114 measures the phase of the GPS signal may be equal to the interval at which the pseudo distance measurement unit 112 measures the pseudo distance, for example.
The phase distance difference measurement unit 114 calculates the amount of change in the distance to the GPS satellite 200 based on the measured amount of change in phase. If the GPS signal is, for example, an L1 signal, 1575.42 MHz, the wavelength λ is about 20 cm. The phase distance difference measuring unit 114 calculates λ × Δθ / 2π (Δθ is the amount of change in phase. The unit is radians) and sets the amount of change in the distance to the GPS satellite 200.
The amount of change in the distance to the GPS satellite 200 calculated in this way is called a phase distance difference.
The phase distance difference measurement unit 114 outputs information indicating the calculated phase distance difference as phase distance difference information.

Using the CPU 911, the multipath determination unit 115 inputs the pseudo distance difference information output from the pseudo distance difference calculation unit 113.
The multipath determination unit 115 uses the CPU 911 to input the phase distance difference information output from the phase distance difference measurement unit 114.
Using the CPU 911, the multipath determination unit 115 compares the pseudo distance change amount (pseudo distance difference) indicated by the input pseudo distance difference information with the phase distance difference indicated by the input phase distance difference information, and receives the received signal. It is determined whether or not the GPS signal received by the device 111 is multipath.
For example, the multipath determination unit 115 uses the CPU 911 to calculate the difference between the pseudo distance difference and the phase distance difference. The multipath determination unit 115 determines that the GPS signal received by the reception device 111 is a multipath when the difference between the pseudorange difference and the phase distance difference is greater than a predetermined threshold (for example, 1 meter). The multipath determination unit 115 determines that the GPS signal is not a multipath when the difference between the pseudorange difference and the phase distance difference is smaller than a predetermined threshold.

The angular velocity measuring unit 121 measures the angular velocity of the positioning terminal device 100 using an angular velocity sensor such as a gyro.
The angular velocity measuring unit 121 outputs information indicating the measured angular velocity as angular velocity information.

The speed measuring unit 122 measures the speed of the positioning terminal device 100 using a speed sensor such as a vehicle speed pulse generator, for example.
The speed measurement unit 122 outputs information indicating the measured speed as speed information.

The position calculation unit 130 uses the CPU 911 to input the pseudo distance information output from the pseudo distance measurement unit 112.
Using the CPU 911, the position calculation unit 130 inputs angular velocity information output by the angular velocity measurement unit 121.
Using the CPU 911, the position calculation unit 130 inputs the speed information output from the speed measurement unit 122.
Using the CPU 911, the position calculation unit 130 rejects the input pseudo distance information corresponding to the GPS signal that the multipath determination unit 115 determines to be multipath.
Here, “rejection” means that the subsequent calculation (in this case, calculation of the current position) is performed assuming that there is no information.

The position calculation unit 130 uses the CPU 911 to calculate the current position of the reception device 111 (positioning terminal device 100) based on the pseudo distance information that has not been rejected. At this time, the position calculation unit 130 calculates the current position using the input angular velocity information and velocity information.
Using the CPU 911, the position calculation unit 130 outputs information indicating the calculated current position as position information.
The position information output by the position calculation unit 130 is notified to the user, for example, by the display device 901 displaying it.

  If the required number (usually four) of GPS signals can be received, the current position of the positioning terminal device 100 can be calculated using only the pseudorange measured based on the GPS signals.

  If the initial position, moving speed, and moving direction of the positioning terminal device 100 are known, the current position of the positioning terminal device 100 can be obtained without a GPS signal. Since the moving speed and moving direction can be obtained from the angular velocity information and the velocity information, if the initial position can be calculated based on the GPS signal, the current position may be obtained using only the angular velocity information and the velocity information. .

However, there are various error factors, and if the current position is calculated using only the pseudo distance measured based on the GPS signal, an accurate position cannot be calculated.
In addition, the necessary number of GPS signals cannot always be received.
Similarly, when only the angular velocity information and the velocity information are used, there are various error factors, and an accurate position cannot be calculated.

  Therefore, the position calculation unit 130 calculates an accurate position with few errors by using both the pseudo distance information, the angular velocity information, and the velocity information.

  Next, multipath will be described.

FIG. 3 is a diagram for explaining multipath.
The GPS signal received by the positioning terminal device 100 includes a direct wave directly flying from the GPS satellite 200 and a multipath such as a reflected wave reflected by an obstacle.
Since the positioning terminal device 100 calculates the position of the positioning terminal device 100 under the assumption that the distance measured based on the GPS signal is a linear distance from the GPS satellite 200, the GPS received by the receiving device 111 is received. When the signal is multipath, the position of the positioning terminal device 100 is erroneously calculated.
Therefore, it is important to determine whether or not the GPS signal received by the receiving device 111 is multipath.

  In this embodiment, the multipath determination unit 115 determines whether or not a multipath, and calculates the accurate position by rejecting the distance measured based on the GPS signal determined to be multipath. .

  Next, the operation will be described.

FIG. 4 is a flowchart showing an example of the flow of positioning processing in which the positioning terminal device 100 in this embodiment calculates the current position.
The positioning process is an example of a measurement method.

  In S11, the receiving device 111 receives a GPS signal. Since the GPS signal is transmitted by each of the plurality of GPS satellites 200, the receiving device 111 receives the plurality of GPS signals.

The processing of S12 to S17 is repeated for each GPS signal received by the receiving device 111.
Moreover, the process of S12-S14 which the pseudo distance measurement part 112 and the pseudo distance difference calculation part 113 perform, and the process of S15-S16 which the phase distance difference measurement part 114 performs are processed in parallel.

  In S12, the pseudo distance measuring unit 112 measures the arrival delay time based on the GPS signal received by the receiving device 111 in S11.

In S13, the pseudo distance measuring unit 112 calculates a pseudo distance based on the arrival delay time measured in S12.
The pseudo distance measuring unit 112 outputs pseudo distance information indicating the calculated pseudo distance.

In S14, the pseudo distance difference calculation unit 113 uses the CPU 911 to input the pseudo distance information output by the pseudo distance measurement unit 112 in S13.
The pseudo distance difference calculation unit 113 uses the CPU 911 to calculate a pseudo distance difference based on the input pseudo distance information.
Using the CPU 911, the pseudo distance difference calculation unit 113 outputs pseudo distance difference information indicating the calculated pseudo distance difference.

In S15, the phase distance difference measuring unit 114 measures the amount of phase change based on the GPS signal received by the receiving device 111 in S11.
The phase distance difference measuring unit 114 calculates the phase distance difference based on the measured phase change amount.
The phase distance difference measurement unit 114 outputs phase distance difference information indicating the calculated phase distance difference.

In S16, the multipath determination unit 115 uses the CPU 911 to input the pseudo distance difference information output from the pseudo distance difference calculation unit 113 in S14 and the phase distance difference information output from the phase distance difference measurement unit 114 in S16. To do.
The multipath determination unit 115 compares the pseudorange difference with the phase distance difference based on the input pseudorange difference information and the input phase distance difference information, and the GPS signal received by the reception device 111 is a multipath. Judge whether there is.
For example, the multipath determination unit 115 uses the CPU 911 to calculate the difference between the pseudo distance difference and the phase distance difference. The multipath determination unit 115 determines that the GPS signal received by the reception device 111 is a multipath when the difference between the pseudorange difference and the phase distance difference is greater than a predetermined threshold. The multipath determination unit 115 determines that the GPS signal is not a multipath when the difference between the pseudorange difference and the phase distance difference is smaller than a predetermined threshold.
When the multipath determination unit 115 determines that the path is multipath, the position calculation unit 130 rejects the pseudo distance corresponding to the GPS signal.

In S <b> 17, the position calculation unit 130 uses the CPU 911 to input the pseudo distance information output from the pseudo distance measurement unit 112 in S <b> 13.
The position calculation unit 130 uses the CPU 911 to calculate the current position based on the pseudo distance indicated by the pseudo distance information that has not been rejected among the input pseudo distance information.

  Of the positioning processes described here, S12 to S17 are multipath determination processes. The positioning process is a process of calculating the current position using the pseudo distance obtained from the GPS signal determined not to be multipath by the multipath determination process.

  Next, the principle of multipath determination will be described.

  FIG. 5 is a diagram for explaining the principle of multipath determination.

  It is assumed that the positioning terminal device 100 is moving in a direction away from the GPS satellite 200.

At time t ₁ , the pseudo distance measurement unit 112 measures the pseudo distance between the positioning terminal device 100 and the GPS satellite 200 based on the GPS signal. Pseudorange measured and _{R t1} at time _{t 1.}
Simultaneously with the measurement of the pseudo distance, the phase distance difference measurement unit 114 measures the phase of the GPS signal. The phase of the GPS signal measured by the phase distance difference measuring unit 114 takes a value between −π and π. In this example, the phase distance difference measuring unit 114 measures the phase of the GPS signal as 0.8π.

In time _{t 2, the} phase distance difference measuring section 114 measures the phase of the GPS signal. In this example, the phase distance difference measuring unit 114 measures the phase of the GPS signal as −0.8π.

Phase distance difference measuring section 114 compares the phase and measured phase and time t ₂ measured at time t _1, to calculate the phase difference. In this example, the phase distance difference measurement unit 114 calculates the phase difference from time t ₁ to time t ₂ to be 0.4π.
Note that the time t _2, the measurement of pseudorange is not performed, only the measurement of the phase.

At time t ₃ , the pseudo distance measuring unit 112 measures the pseudo distance between the positioning terminal device 100 and the GPS satellite 200 based on the GPS signal. A pseudo-distance measured and _{R t3} to time _{t 3.}
Pseudo distance difference calculation unit 113, a pseudo-range _{R t1} measured at time t1, the pseudorange _{R t3} Metropolitan measured at time _{t 3,} and calculates the pseudo distance difference ΔR _p = _R t3 _{-R t1.}

Simultaneously with the measurement of the pseudo distance, the phase distance difference measurement unit 114 measures the phase of the GPS signal. In this example, the phase distance difference measuring unit 114 measures the phase of the GPS signal as −0.4π.
Phase distance difference measuring section 114 compares the the phase measurement in the phase and time t ₃ when measured in time t _2, the calculated phase difference. In this example, the phase distance difference measurement unit 114 calculates the phase difference from time t ₂ to time t ₃ to be 0.4π.

Phase distance difference measuring unit 114 sums the phase difference from time t ₁ to time t _3, and calculates the amount of phase change. In this example, the phase distance difference measuring unit 114 calculates the amount of phase change as 0.8π.
The phase distance difference measuring unit 114 calculates the phase distance difference ΔR _c based on the calculated phase change amount. In this example, the phase distance difference measurement unit 114 calculates the phase distance difference ΔR _c as 8 centimeters.

If there is no multipath, the phase distance difference ΔR _c calculated by the phase distance difference measurement unit 114 and the pseudo distance difference ΔR _p calculated by the pseudo distance difference calculation unit 113 should match.
In practice, due to various error factors, the pseudo distance measured based on the GPS signal may include an error of about 1 m.

The multipath determination unit 115 calculates a difference ΔR between the pseudo distance difference ΔR _p and the phase distance difference ΔR _c . The multipath determining unit 115 determines that the GPS signal is not multipath if the absolute value of ΔR is 1 m or less. If the absolute value of ΔR exceeds 1 m, it is determined that the GPS signal is multipath.
In this example, the multipath determination unit 115 determines that the GPS signal is not a multipath.
Therefore, the position calculation unit 130 obtains the current position of the positioning terminal device 100 using the pseudo distance obtained from the GPS signal. Note that the position calculation unit 130 obtains the current position in consideration of other information. The other information includes, for example, the angular velocity measured by the angular velocity measuring unit 121, the velocity measured by the velocity measuring unit 122, and the GPS signal that the multipath determination unit 115 determines as not multipath among other GPS signals received at the same time. The obtained pseudo distance and the like. However, the pseudorange obtained from the GPS signal that the multipath determination unit 115 determines to be multipath is not used.

At time _{t 4,} the phase distance difference measuring section 114 measures the phase of the GPS signal. In this example, the phase distance difference measurement unit 114 measures the phase of the GPS signal as 0.
Phase distance difference measuring section 114 compares the phase and measured phase and time t ₄ when measured at time t _3, and calculates the phase difference. In this example, the phase distance difference measuring section 114, the phase difference from time t ₃ to time t ₄ is calculated to be 0.4Pai.
Note that the time t _4, the measurement of pseudorange is not performed, only the measurement of the phase.

At time _{t 5,} the pseudo-distance measurement unit 112, based on the GPS signal, to measure the pseudorange between the positioning terminal device 100 and GPS satellites 200. The pseudo-distance measured at time _{t 5,} and _{R t5.}
Here, the multipath is generated strong reflected on an obstacle at a time t _5, the receiving apparatus 111 is receiving a GPS signal due to a strong multi-path than the direct wave. For this reason, the transmission delay time from the GPS satellite 200 to the positioning terminal device 100 becomes long, and the pseudo distance R _t5 measured by the pseudo distance measuring unit 112 is larger than the actual distance between the positioning terminal device 100 and the GPS satellite 200. (In this example, one wavelength is longer).

The pseudo distance difference calculation unit 113 calculates a pseudo distance difference ΔR _p = R _t5 −R _t3 from the pseudo distance R _t3 measured at time t ₃ and the pseudo distance measured at time t ₅ . In this example, since the pseudo distance R _t5 is longer than the actual distance due to the influence of the multipath, the pseudo distance difference ΔR _p is also larger than the actual relative distance change.

Simultaneously with the measurement of the pseudo distance, the phase distance difference measurement unit 114 measures the phase of the GPS signal. In this example, the phase distance difference measurement unit 114 measures the phase of the GPS signal as 0.
Phase distance difference measuring section 114 compares the phase of the measured phase and the time t ₅ measured at time t _4, and calculates the phase difference. In this example, the phase distance difference measuring section 114, the phase difference from time t ₄ to time t ₅ calculates to be 0.

When the propagation distance of the GPS signal changes due to the multipath, the phase of the GPS signal suddenly changes, so that the multipath may be determined.
However, as in this example, there are cases where the phase of the GPS signal does not change so much, and it is not possible to correctly determine the multipath only by monitoring an abnormal change in the phase of the GPS signal.

Phase distance difference measuring unit 114 sums the phase difference from time t ₃ to time t _5, and calculates the amount of phase change from time t ₃ to time t _5. In this example, the phase distance difference measurement unit 114 calculates the phase change amount to be 0.4π.
The phase distance difference measuring unit 114 calculates the phase distance difference ΔR _c based on the calculated phase change amount. In this example, the phase distance difference measurement unit 114 calculates the phase distance difference ΔR _c to be 4 centimeters.
The phase distance difference ΔR _c calculated by the phase distance difference measuring unit 114 cannot be measured correctly from the time t ₄ to the time t ₅ due to the influence of multipath, and therefore is smaller than the actual change in the relative distance. It has become.

Thus, even when the affected same multipath, an error appearing in the pseudo distance difference [Delta] R _p, with an error appearing in the phase distance difference [Delta] R _c is illusory error is different.
For example, the pseudo-range difference ΔR _p may fly several hundred meters in an instant when a multipath occurs. On the other hand, the phase distance difference ΔR _c is within the range of the corresponding distance (that is, one wavelength) because the measurable phase difference is at most 2π.
Therefore, by comparing the pseudo distance difference ΔR _p with the phase distance difference ΔR _c , it is possible to determine whether or not there is multipath.

Multipath determination unit 115 calculates the difference [Delta] R between the pseudo distance difference [Delta] R _p and the phase distance difference [Delta] R _c, it is determined whether multi-path.
In this example, the multipath determination unit 115 determines that the GPS signal is multipath.
Therefore, the position calculation unit 130 rejects the pseudo distance measured based on the GPS signal and does not use it as information for calculating the current position. The position calculation unit 130 calculates the current position of the positioning terminal device 100 based on other information. The other information includes, for example, the angular velocity measured by the angular velocity measuring unit 121, the velocity measured by the velocity measuring unit 122, and the GPS signal that the multipath determination unit 115 determines as not multipath among other GPS signals received at the same time. The obtained pseudo distance and the like.

FIG. 6 is a diagram for explaining the principle of multipath determination when the phase measurement interval and the pseudo-range measurement interval are equal.
As described above, the interval at which the phase distance difference measurement unit 114 measures the phase may be the same as the interval at which the pseudo distance measurement unit 112 measures the pseudo distance.

Unlike the case of FIG. 5, the phase distance difference measurement unit 114 does not measure the phase at times t ₂ and t ₄ , and the times t ₁ and t are the same time as the time when the pseudo distance measurement unit 112 measures the pseudo distance. in _{3, t 5} only, to measure the phase.
The phase distance difference measuring unit 114 calculates a phase difference based on the measured phase. For example, the phase difference between time t ₁ and time t ₃ is calculated as 0.8π, and the phase difference between time t ₃ and time t ₅ is calculated as 0.4π.
The phase distance difference measurement unit 114 calculates the phase distance difference based on the calculated phase difference. For example, the phase distance difference between time t ₁ and time t ₃ is calculated as 0.8λ / 2, and the phase difference between time t ₃ and time t ₅ is calculated as 0.4λ / 2.
Thus, even when the interval at which the phase distance difference measuring unit 114 measures the phase is equal to the interval at which the pseudo distance measuring unit 112 measures the pseudo distance, the phase distance difference measuring unit 114 is the same as the case described with reference to FIG. Then, the phase distance difference is calculated. Therefore, based on this, it is possible to determine whether or not the multipath determination unit 115 is multipath.

Note that when the number of GPS signals that can be received by the receiving device 111 is small, or when the multipath is likely to occur such as an area where a high-rise building stands, the multipath determination unit 115 determines that the multipath is multipath. By rejecting the pseudo distance measured based on the GPS signal, there is a possibility that there is no pseudo distance that can be used to calculate the current position.
When there is no pseudo distance that can be used to calculate the current position, the position calculation unit 130 calculates the current position based on the angular velocity information and the velocity information.
The angular velocity information and the velocity information may include a bias error, a scale factor error, and the like due to errors in the gyroscope and the vehicle speed pulse generator.

The position calculation unit 130 calculates a more accurate current position by using both the pseudo distance and the angular velocity information and the velocity information when there is no multipath, and what error is in the angular velocity information and the velocity information. Know beforehand if it is included.
As a method for grasping in advance the angular velocity information and the error included in the velocity information, for example, there is a method using a Kalman filter.

When there is no more pseudo distance that can be used, the position calculation unit 130 calculates the current position based on angular velocity information and velocity information obtained by correcting an error that has been grasped in advance.
Therefore, the position calculation unit 130 can calculate a relatively accurate current position even when there is no pseudo distance that can be used.

Also, if multipaths in the same state continue to occur, there is no jump in the phase of the GPS signal, so the pseudorange difference and the phase distance difference are almost the same value. In the determination method in this embodiment, Multipath cannot be determined.
However, since what kind of multipath occurs depends on the positional relationship between the positioning terminal device 100, the GPS satellite 200, and the obstacle, normally, the multipath in the same state does not continuously occur. The path state always changes.
Therefore, the multipath can be correctly determined by the determination method in this embodiment.

In addition, when the GPS signal changes from the multipath state to the normal state, the GPS signal phase jumps. Therefore, in the determination method according to this embodiment, when the GPS signal returns to the normal state, Cannot be distinguished from when a pass occurs.
Therefore, in the determination method according to this embodiment, one time when the difference between the pseudo-range difference and the phase distance difference becomes large is determined as multipath, and that one time is rejected. If the difference between the pseudo-range difference and the phase distance difference becomes small in the next measurement, it is determined that the path is not multipath and is used for position calculation.

In addition, since the multipath state usually changes constantly, there is a possibility that the difference between the pseudorange difference and the phase distance difference has been reduced by chance.
Therefore, after determining that the path is multipath, even if the difference between the pseudorange difference and the phase distance difference becomes small, it is not adopted immediately, and the state where the difference between the pseudorange difference and the phase distance difference is small is a predetermined time. It may be determined that the path is not multipath only when it is continued.
For example, the multipath determination unit 115 uses the storage device 920 to store the number of stable times. When the difference between the pseudo-range difference and the phase distance difference is larger than a predetermined threshold, the multipath determination unit 115 resets the stable count to 0 using the CPU 911. In addition, when the difference between the pseudo-range difference and the phase distance difference is smaller than a predetermined threshold, the multipath determination unit 115 uses the CPU 911 to add 1 to the stable count. The multipath determination unit 115 determines that the path is multipath when the stable count is smaller than the predetermined count, and determines that the path is not multipath when the stable count is greater than the predetermined count.
As a result, if the GPS signal is not multipath and can be received normally, the state is stable, so it returns to the normal state, and after a predetermined time has passed, it is determined that it is not multipath correctly and used for position calculation can do.

  It may be combined with other multipath determination methods. For example, the GPS signal that the multipath determination unit 115 in this embodiment determines to be not multipath may be further determined by other multipath determination methods as to whether or not it is multipath. Thereby, since a more accurate determination can be performed, a more accurate position can be calculated.

The positioning terminal device 100 (measurement device) in this embodiment is
A processing device (CPU 911) for processing information;
A receiving device 111 for receiving radio waves transmitted by a transmitting device (GPS satellite 200);
The arrival delay time of the radio wave (GPS signal) received by the reception device 111 is measured, the distance (pseudo distance) to the transmission device (GPS satellite 200) is calculated based on the measured arrival delay time, and the calculated distance ( Pseudo distance measurement unit 112 that outputs information indicating pseudo distance) as pseudo distance information;
Using the processing device (CPU 911), the pseudo distance information output from the pseudo distance measuring unit 112 is input, and using the processing device (CPU 911), based on the input pseudo distance information, to the transmitting device (GPS satellite 200). Pseudo distance difference calculation is performed by calculating a distance change amount (pseudo distance difference) and outputting information indicating the calculated distance change amount (pseudo distance difference) as pseudo distance difference information using the processing device (CPU 911). Part 113;
The amount of change in the phase of the radio wave (GPS signal) received by the receiver 111 is measured, and the amount of change in the distance to the transmitter (GPS satellite 200) (phase distance difference) is calculated based on the measured amount of change in phase. A phase distance difference measurement unit 114 that outputs information indicating the calculated distance change amount (phase distance difference) as phase distance difference information;
Using the processing device (CPU 911), the pseudo distance difference information output from the pseudo distance difference calculation unit 113 and the phase distance difference information output from the phase distance difference measurement unit 114 are input, and the processing device (CPU 911) is used. The radio wave received by the reception device 111 by comparing the distance change amount (pseudo distance difference) indicated by the input pseudo distance difference information with the distance change amount (transfer distance difference) indicated by the input phase distance difference information. A multipath determination unit 115 that determines whether or not (GPS signal) is a multipath;
It is characterized by having.

  According to the positioning terminal device 100 (measurement device) in this embodiment, the multipath determination unit 115 compares the pseudo-range difference and the phase distance difference, and the radio wave (GPS signal) received by the reception device 111 is multi-valued. Since it is determined whether or not it is a pass, it is possible to accurately determine whether or not it is a multi-pass.

The positioning terminal device 100 (measurement device) in this embodiment is
The multi-path determining unit 115
Compare the distance change amount (pseudo distance difference) indicated by the input pseudo distance difference information with the distance change amount (phase distance difference) indicated by the input phase distance difference information. When the value is larger than a predetermined threshold, the radio wave (GPS signal) received by the receiving device 111 is determined to be multipath.

  According to the positioning terminal device 100 (measuring device) in this embodiment, when the multipath determination unit 115 determines that the absolute value of the difference between the pseudo-range difference and the phase distance difference is greater than a predetermined threshold, the receiving device 111 Since it is determined that the received radio wave (GPS signal) is multipath, it is possible to accurately determine whether or not it is multipath.

The positioning terminal device 100 (measurement device) in this embodiment is
The multipath determination unit 115
Compare the distance change amount (pseudo distance difference) indicated by the input pseudo distance difference information with the distance change amount (phase distance difference) indicated by the input phase distance difference information. When the state where the value is smaller than a predetermined threshold value continues for a predetermined time, it is determined that the radio wave (GPS signal) received by the reception device 111 is not multipath.

  According to positioning terminal apparatus 100 (measurement apparatus) in this embodiment, multipath determination unit 115 continues for a predetermined time when the absolute value of the difference between the pseudo-range difference and the phase distance difference is smaller than a predetermined threshold. In this case, since the radio wave (GPS signal) received by the receiving device 111 is determined not to be multipath, even if the difference between the pseudo distance difference and the phase distance difference is accidentally reduced during multipath generation, no erroneous determination is made. There is an effect that it is possible to accurately determine whether or not it is multipath.

The positioning terminal device 100 (measurement device) in this embodiment is
The receiving device 111 receives a plurality of radio waves (GPS signals) transmitted by a plurality of transmitting devices (GPS satellites 200) whose positions are known,
The measurement device (positioning terminal device 100)
Using the processing device (CPU 911), a plurality of pseudo distance information output by the pseudo distance measuring unit 112 corresponding to a plurality of radio waves (GPS signals) received by the receiving device 111 is input, and the processing device (CPU 911) is used. Then, the pseudo-range information corresponding to the radio wave (GPS signal) that the multi-path determining unit 115 determines to be multi-path among the plurality of input pseudo-range information is rejected and input using the processing device (CPU 911). It has the position calculation part 130 which calculates the position of the receiver 111 based on the pseudo distance information which was not rejected among the plurality of pseudo distance information.

  According to positioning terminal device 100 (measuring device) in this embodiment, position calculation unit 130 rejects pseudorange information corresponding to the radio wave (GPS signal) that multipath determination unit 115 determines to be multipath. Since the position of the receiving device 111 is calculated based on the pseudo-range information that has not been rejected, there is no deterioration in positioning accuracy due to the influence of disturbance due to multipath, and an accurate position can be calculated.

The positioning terminal device 100 (measurement device) in this embodiment is
The pseudo distance measuring unit 112 is
The distance to the transmitter (GPS satellite 200) is repeatedly calculated at a predetermined cycle, and pseudorange information is repeatedly output.
The measurement device (positioning terminal device 100) further includes a storage device 920 that stores information,
The pseudo-range difference calculating unit 113
Using the storage device 920, a plurality of pseudo distance information repeatedly output by the pseudo distance measuring unit 112 is stored,
A processing device (CPU 911) is used to calculate the amount of change (pseudo distance difference) in the distance to the transmission device (GPS satellite 200) based on the stored plurality of pseudo distance information.

  According to the positioning terminal device 100 (measuring device) in this embodiment, the pseudo distance difference calculating unit 113 calculates the pseudo distance difference based on the pseudo distance repeatedly measured by the pseudo distance measuring unit 112. When the state changes, the pseudo-range difference becomes an abnormal value, and there is an effect that the multipath determination unit 115 can correctly determine the multipath.

The positioning terminal device 100 (measurement device) in this embodiment is
The phase distance difference measuring unit 114 is
The phase of the radio wave (GPS signal) received by the receiving device 111 is repeatedly measured at a predetermined cycle, and the phase difference is calculated based on the measured phase and the previously measured phase, and is calculated within a predetermined period. The phase change amount is obtained by summing up the phase differences.

  According to the positioning terminal device 100 (measurement device) in this embodiment, the phase distance difference measurement unit 114 repeatedly measures the phase of the radio wave (GPS signal) received by the reception device 111 to obtain the amount of phase change. Therefore, when the multipath state changes, the phase jumps, the phase distance difference becomes an abnormal value, and there is an effect that the multipath determination unit 115 can correctly determine the multipath.

The multipath determination process (multipath determination method) in this embodiment is
A radio wave received by a multipath determination device (positioning terminal device 100) having a processing device (CPU 911) for processing information and a receiving device 111 for receiving a radio wave (GPS signal) transmitted by a transmission device (GPS satellite 200). In the multipath determination method for determining whether (GPS signal) is multipath,
Measure the arrival delay time of the radio wave (GPS signal) received by the receiver 111,
Based on the measured arrival delay time, the distance to the transmitter (GPS satellite 200) is calculated,
The information indicating the calculated distance is set as pseudo-range information,
Based on the pseudo distance information, the processing device (CPU 911) calculates the amount of change (pseudo distance difference) in the distance to the transmitting device (GPS satellite 200),
Information indicating the calculated distance change amount (pseudo distance difference) is referred to as pseudo distance difference information.
Measure the amount of change in the phase of the radio wave (GPS signal) received by the receiver 111,
Based on the measured phase variation, calculate the distance variation (phase distance difference) to the transmitter,
Information indicating the calculated distance change amount (phase distance difference) is the phase distance difference information,
The processing device (CPU 911) compares the distance change amount (pseudo distance difference) indicated by the pseudo distance difference information with the distance change amount (phase distance difference) indicated by the phase distance difference information, and the receiving device It is characterized in that it is determined whether or not the received radio wave is multipath.

  According to the multipath determination process (multipath determination method) in this embodiment, the pseudo-range difference and the phase distance difference are compared to determine whether or not the radio wave received by the reception device 111 is multipath. As a result, the multipath can be accurately determined.

The multipath determination process (multipath determination method) in this embodiment is
The processing device (CPU 911) compares the distance change amount (pseudo distance difference) indicated by the pseudo distance difference information with the distance change amount (phase distance difference) indicated by the phase distance difference information, and changes the distance. When the absolute value of the amount difference is larger than a predetermined threshold, it is determined that the radio wave received by the receiving device is multipath.

  According to the multipath determination process (multipath determination method) in this embodiment, when the absolute value of the difference between the pseudorange difference and the phase distance difference is greater than a predetermined threshold, the radio wave (GPS Signal) is determined to be multipath, so that it is possible to accurately determine whether or not the signal is multipath.

The multipath determination process (multipath determination method) in this embodiment is
The processing device (CPU 911) compares the distance change amount (pseudo distance difference) indicated by the pseudo distance difference information with the distance change amount (phase distance difference) indicated by the phase distance difference information, and changes the distance. When the state where the absolute value of the difference in amount is smaller than a predetermined threshold value continues for a predetermined time, it is determined that the radio wave received by the reception device 111 is not multipath.

  According to the multipath determination process (multipath determination method) in this embodiment, the multipath determination unit 115 is in a state where the absolute value of the difference between the pseudorange difference and the phase distance difference is smaller than a predetermined threshold. Since it is determined that the radio wave (GPS signal) received by the receiving device 111 is not multipath when the time continues, even if the difference between the pseudo-range difference and the phase distance difference is accidentally reduced during multipath generation, an erroneous determination is made. Without the effect, it is possible to accurately determine whether or not the multipath.

The positioning process (measurement method) in this embodiment is:
Measurement is performed by a measuring device (positioning terminal device 100) having a processing device (CPU 911) that processes information and a receiving device 111 that receives a radio wave (GPS signal) transmitted by a transmitting device (GPS satellite 200) whose position is known. In the measurement method
Measure the arrival delay time of the radio wave (GPS signal) received by the receiver 111,
Based on the measured arrival delay time, the distance (pseudo distance) to the transmission device (GPS satellite 200) is calculated,
The information indicating the calculated distance is set as pseudo-range information,
The processing device (CPU 911) calculates a change amount (pseudo distance difference) of the distance to the transmission device (GPS satellite 200) based on the pseudo distance information,
Information indicating the calculated distance change amount (pseudo distance difference) is referred to as pseudo distance difference information.
Measure the amount of change in the phase of the radio wave (GPS signal) received by the receiver 111,
Based on the measured phase change amount, the distance change amount (phase distance difference) to the transmission device (GPS satellite 200) is calculated,
Information indicating the calculated distance change amount (phase distance difference) is the phase distance difference information,
The processing device (CPU 911) compares the distance change amount (pseudo distance difference) indicated by the pseudo distance difference information with the distance change amount (phase distance difference) indicated by the phase distance difference information, and receives the receiving device 111. Determines whether the received radio wave (GPS signal) is multipath,
The processing device (CPU 911) rejects the pseudo distance information corresponding to the radio wave determined to be multipath among the pseudo distance information indicating the pseudo distance calculated corresponding to the radio wave received by the receiving device 111,
The processing device (CPU 911) calculates the position of the reception device 111 based on the pseudo distance information that has not been rejected among the pseudo distance information.

  According to the positioning process (measurement method) in this embodiment, the pseudorange information corresponding to the radio wave (GPS signal) determined to be multipath is rejected, and based on the pseudorange information not rejected, the receiving device Since the position 111 is calculated, the positioning accuracy is not deteriorated due to the influence of the disturbance due to multipath, and the accurate position can be calculated.

Note that the phase distance difference measurement unit 114 described above calculates the phase distance difference by measuring the amount of phase change, but the phase distance difference may be calculated by other methods.
For example, the phase change may be calculated by measuring the amount of phase change by counting the wave number of a GPS signal or an intermediate frequency signal obtained by frequency conversion of the GPS signal.

FIG. 7 is a diagram for explaining the operation of the method of calculating the phase distance difference by counting the wave number of the GPS signal.
Since the frequency of the GPS signal is, for example, 1575.42 MHz, the wave number that reaches the positioning terminal device 100 within 250 milliseconds is 39385 million unless the distance between the positioning terminal device 100 and the GPS satellite 200 changes. 5,000.
However, when the positioning terminal device 100 (or the GPS satellite 200) moves and the distance between the positioning terminal device 100 and the GPS satellite 200 changes, the wave number that reaches within the same time changes.
For example, when the distance between the positioning terminal device 100 and the GPS satellite 200 is increased by two wavelengths, the wave number to reach is reduced by two. This means that the phase of the GPS signal is delayed by two wavelengths (4π).
Therefore, when the signal is normal, the amount of change in the phase of the GPS signal can be measured by counting the wave number of the GPS signal or the intermediate frequency signal obtained by frequency-converting the GPS signal.

When multipath occurs, the phase of the GPS signal suddenly changes. In the example of the figure, although it is delayed by about 4.5 wavelengths (9π), it does not appear as a change in the wave number reaching the positioning terminal device 100.
Therefore, even if the phase distance difference is calculated based on the amount of phase change measured by counting the wave number, the pseudo distance difference and the phase distance difference greatly differ due to the occurrence of multipath. The path determination unit 115 can correctly determine multipath.

The positioning terminal device 100 in this embodiment is
In the positioning terminal device 100 that performs positioning by receiving GPS signals (radio waves) from the GPS satellite 200 (transmitting device) in the sky, the following is performed in order to eliminate the influence of disturbance due to multipath.
(1) Calculate a difference ΔR _p = R _p2 −R _p1 between pseudo distances before and after the movement of the vehicle or the like. Here, _Rp1 is a pseudo distance obtained at the position before the movement (a distance obtained by calculating the distance between the GPS satellite and the vehicle based on the time difference), and R _p2 is a pseudo distance obtained at the position after the movement.
(2) Distance difference due to phase: ΔR _c = λ × n is calculated. This is the distance difference before and after movement obtained from the phase information, λ is the wavelength of the GPS signal, and n is the wave number that fluctuates before and after movement.
(3) A difference ΔR (= ΔR _p −ΔR _c ) between ΔR _p and ΔR _c is calculated.
(4) If the difference ΔR (absolute value) is a predetermined value (for example, 1 m) or more, it is determined that there is a disturbance such as multipath, and the GPS signal from the GPS satellite is not used for the positioning calculation and rejected. To do.

  Thereby, even in densely populated areas (such as building streets) where high buildings are lined up, positioning accuracy is not deteriorated due to the influence of multipath, and accurate GPS positioning can be performed.

1 is a system configuration diagram illustrating an example of an overall configuration of a positioning system 800 according to Embodiment 1. FIG. FIG. 3 is a block configuration diagram showing an example of a block configuration of the positioning terminal device 100 according to the first embodiment. The figure for demonstrating multipath. The flowchart figure which shows an example of the flow of the positioning process in which the positioning terminal device 100 in Embodiment 1 calculates a present position. The figure for demonstrating the principle of a multipass determination. The figure for demonstrating the principle of multipath determination in case a phase measurement interval and a pseudo distance measurement interval are equal. The figure for demonstrating the operation | movement of the system which counts the wave number of a GPS signal and calculates a phase distance difference.

Explanation of symbols

  100 positioning terminal device, 111 receiving device, 112 pseudo distance measuring unit, 113 pseudo distance difference calculating unit, 114 phase distance difference measuring unit, 115 multipath judging unit, 121 angular velocity measuring unit, 122 speed measuring unit, 130 position calculating unit, 200 GPS satellite, 901 display device, 911 CPU, 920 storage device.

Claims (11)

A processing device for processing information;
A receiving device for receiving radio waves transmitted by the transmitting device;
Pseudo distance that measures the arrival delay time of the radio wave received by the receiving device, calculates the distance to the transmitting device based on the measured arrival delay time, and outputs information indicating the calculated distance as pseudo distance information A measurement unit;
Using the processing device, the pseudo distance information output by the pseudo distance measuring unit is input, and using the processing device, the change amount of the distance to the transmitting device is calculated based on the input pseudo distance information. A pseudo distance difference calculation unit that outputs information indicating the calculated amount of change in the distance as pseudo distance difference information using the processing device;
The amount of change in the phase of the radio wave received by the receiving device is measured, the amount of change in the distance to the transmitting device is calculated based on the amount of change in the measured phase, and information indicating the amount of change in the calculated distance is obtained. A phase distance difference measurement unit that outputs as phase distance difference information;
Using the processing device, the pseudo distance difference information output from the pseudo distance difference calculation unit and the phase distance difference information output from the phase distance difference measurement unit are input, and the pseudo value input using the processing device is input. Multipath determination that compares the distance change amount indicated by the distance difference information with the distance change amount indicated by the input phase distance difference information to determine whether or not the radio wave received by the receiving device is multipath. And
A measuring apparatus comprising: The multipath determination unit
When the amount of change in distance indicated by the input pseudo-range difference information is compared with the amount of change in distance indicated by the input phase distance difference information, and the absolute value of the difference in distance change is greater than a predetermined threshold, The measuring apparatus according to claim 1, wherein the radio wave received by the receiving apparatus is determined to be multipath. The multipath determination unit
Comparing the amount of change in distance indicated by the input pseudo distance difference information with the amount of change in distance indicated by the input phase distance difference information, the state where the absolute value of the difference in distance change is smaller than a predetermined threshold value, The measuring apparatus according to claim 1, wherein the radio wave received by the receiving apparatus is determined not to be multipath when the predetermined period of time is continued. The receiving device receives a plurality of radio waves transmitted by a plurality of transmitting devices whose positions are known,
The measuring device further includes:
Using the processing device, input a plurality of pseudo distance information output by the pseudo distance measuring unit corresponding to a plurality of radio waves received by the receiving device, and input the plurality of pseudo distances using the processing device. Among the information, the pseudo-range information corresponding to the radio wave determined to be multi-path by the multi-path determination unit is rejected, and the pseudo-range information not rejected among the plurality of input pseudo-range information using the processing device. The measuring apparatus according to claim 1, further comprising a position calculating unit that calculates a position of the receiving apparatus based on distance information. The pseudo distance measuring unit is
The distance to the transmitter is repeatedly calculated at a predetermined cycle, and pseudo-range information is repeatedly output.
The measuring device further includes a storage device for storing information,
The pseudo-range difference calculation unit
Using the storage device, a plurality of pseudo distance information repeatedly output by the pseudo distance measurement unit,
The measuring device according to claim 1, wherein the processing device is used to calculate the amount of change in the distance to the transmitting device based on a plurality of stored pseudo distance information. The phase distance difference measuring unit is
The phase of the radio wave received by the receiver is repeatedly measured at a predetermined cycle, and a phase difference is calculated based on the measured phase and the previously measured phase, and the calculated phase difference is calculated within a predetermined period. The measuring apparatus according to claim 1, wherein the phase change amount is obtained by summing. In a multipath determination method in which a measurement device having a processing device that processes information and a reception device that receives a radio wave transmitted by a transmission device determines multipath,
Measure the arrival delay time of the radio wave received by the receiver,
Based on the measured arrival delay time, calculate the distance to the transmitting device,
The information indicating the calculated distance is set as pseudo-range information,
The processing device calculates a change amount of the distance to the transmission device based on the pseudo distance information,
Information indicating the calculated amount of change in distance is used as pseudo-range difference information,
Measure the amount of change in the phase of the radio wave received by the receiver,
Based on the measured amount of phase change, calculate the amount of change in the distance to the transmitter,
Information indicating the calculated distance change amount is phase distance difference information,
Whether the radio wave received by the receiving device is a multipath by comparing the amount of change of the distance indicated by the pseudo-range difference information with the amount of change of the distance indicated by the phase distance difference information. A multipath determination method characterized by determining The multipath determination method is as follows.
The processing device compares the distance change amount indicated by the pseudo distance difference information with the distance change amount indicated by the phase distance difference information, and the absolute value of the difference in distance change is greater than a predetermined threshold value. In this case, the multipath determination method according to claim 7, wherein the radio wave received by the receiving apparatus is determined to be multipath. The multipath determination method is as follows.
The processing device compares the distance change amount indicated by the pseudo distance difference information with the distance change amount indicated by the phase distance difference information, and the absolute value of the difference in distance change is smaller than a predetermined threshold value. 8. The multipath determination method according to claim 7, wherein when the state continues for a predetermined time, it is determined that the radio wave received by the receiving device is not multipath. In a measurement method in which a measurement device having a processing device that processes information and a reception device that receives a radio wave transmitted by a transmission device whose position is known, performs measurement.
Measure the arrival delay time of the radio wave received by the receiver,
Based on the measured arrival delay time, calculate the distance to the transmitting device,
The information indicating the calculated distance is set as pseudo-range information,
The processing device calculates a change amount of the distance to the transmission device based on the pseudo distance information,
Information indicating the calculated amount of change in distance is used as pseudo-range difference information,
Measure the amount of change in the phase of the radio wave received by the receiver,
Based on the measured amount of phase change, calculate the amount of change in the distance to the transmitter,
Information indicating the calculated distance change amount is phase distance difference information,
Whether the radio wave received by the receiving device is a multipath by comparing the amount of change of the distance indicated by the pseudo-range difference information with the amount of change of the distance indicated by the phase distance difference information. Judging
The processing device rejects the pseudo distance information corresponding to the radio wave determined to be multipath out of the pseudo distance information indicating the pseudo distance calculated corresponding to the radio wave received by the receiving device,
The said processing apparatus calculates the position of the said receiving apparatus based on the pseudo distance information which was not rejected among the said pseudo distance information, The measuring method characterized by the above-mentioned. The measurement method is
The processing device compares the distance change amount indicated by the pseudo distance difference information with the distance change amount indicated by the phase distance difference information, and the absolute value of the difference in distance change is greater than a predetermined threshold value. In this case, it is determined that the radio wave received by the receiving device is multipath.

Images