JP2001208821A - Receiver for positioning, and method of processing positioning information applied therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance positioning precision while reducing a cost and weight, and miniaturizing a size. SOLUTION: Satellite signals from plural GPS satellites are received by an antenna 11, ephemeris data of the GPS satellites and observstion data including pseudo-distance data to the GPS satellites are extracted, by a receiption control part 200, from the received signals processed with base 101-10N, error componentys are removed, by an error component removing part 301, from the observation data for the plural GPS satellites based on an error estimated value provided separately, a position of an own receiver is measured thereafter by a positioning and computing part 302, and the error estimated value caused by a multi-path, an SA, a Sagnac, an ionised layer, a troposphere, a reception clock and a noise is found using positioning data found by an error component estimating part 303 to be output to the error component removing part 301.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positioning receiving apparatus that measures the position of its own apparatus using a positioning satellite such as a GPS satellite, and a positioning information processing method applied to the apparatus.

[0002]

2. Description of the Related Art Conventionally, a GPS (Globa) has been used in a position measuring system for measuring the position of a receiving device using a positioning satellite.
l Positioning System). This type of system
Positioning is performed by receiving satellite signals from four GPS satellites with a GPS receiver.

In the above-mentioned GPS, a satellite signal transmitted from a GPS satellite includes an error component given during propagation and an error component given intentionally, and these error components greatly affect positioning accuracy. Therefore, the reliability in positioning is reduced.

On the other hand, in the conventional GPS, a satellite signal from a GPS satellite is multiplexed with two mutually orthogonal frequencies,
The GPS receiver uses two frequencies to remove an error component given during propagation, thereby improving the positioning accuracy. However, causing the GPS receiver to execute the process using the two frequencies requires a processor having a high processing capability, which is a major obstacle to reducing the size and weight of the GPS receiver and reducing the cost.
Therefore, conventionally, it has been strongly desired to improve the positioning accuracy by using an inexpensive GPS receiver.

[0005]

SUMMARY OF THE INVENTION Conventionally considered G
The PS uses two frequencies multiplexed in a satellite signal from a GPS satellite to remove an error component given during propagation in order to improve positioning accuracy. The processing burden is increased, which is a major obstacle in reducing the size and weight of the device and reducing the price, and there is a problem that it is not possible to achieve the demand for improving the positioning accuracy with an inexpensive device.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a positioning receiving apparatus capable of improving the positioning accuracy while reducing the size and weight of the apparatus, and a positioning information processing method applied to the apparatus. .

[0007]

According to the present invention, there is provided a positioning receiving apparatus for measuring the position of an own apparatus by using a positioning satellite, wherein the position of the positioning satellite is determined from a plurality of positioning satellites. Receiving means for receiving a satellite signal including information and transmission time information, and observation information extracting means for extracting observation information including position information of a positioning satellite and distance information to the positioning satellite from a reception signal obtained by the receiving means, An error component removing unit that removes an error component from the observation information extracted by the observation information extracting unit based on the given error estimation information, and a positioning operation that calculates the position of the own apparatus from the observation information obtained by the error component removing unit Means, and the positioning information obtained by the positioning calculation means, and the error estimation information for estimating the error component with a maximum estimated probability is given to the error component removing means. Obtain is obtained by so and a error component estimator.

The error component may be caused by multipath, selection availability, orbit change in a positioning satellite, ionosphere, troposphere, reception clock, and noise.

The error component estimating means stops the error estimating information calculating process for the error component removing means when the positioning information obtained by the positioning calculating means converges to a predetermined value.

The error component removing means is provided with a filter for removing an error component outside a predetermined signal band from the observation information.

According to this configuration, satellite signals from a plurality of positioning satellites are received, and observation information including position information of the positioning satellites and distance information to the positioning satellites is extracted from the received signals, and these plurality of positioning satellites are extracted. After the error component is removed based on the error estimation information separately provided from the observation information for the satellite, the position of the own device is measured, and the multipath, the selection availability, the positioning satellite Error estimation information based on the orbit change, ionosphere, troposphere, reception clock, and noise due to the above, and the error component based on the obtained error estimation information is repeatedly subtracted from the extracted observation information. That is, the error component calculation process and the error component removal process are repeatedly executed until the positioning information converges to the predetermined value, and the error component due to noise is removed by the filter that removes the error component outside the predetermined signal band. Will be.

For this reason, by repeatedly executing the error component calculation process and the error component removal process by feedback, only one frequency needs to be received.
Since there is no need to process two frequencies, the processing capability of the processor can be reduced, so that the positioning accuracy can be improved while reducing the size and weight of the device and reducing the price.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a circuit block diagram showing an embodiment of a GPS receiver according to the present invention. FIG. 2 is a diagram showing a positional relationship between the GPS receiver and a plurality of GPS satellites and a positioning concept.

In FIG. 1, for example, a GPS transmitted from a GPS satellite and including ephemeris data and transmission time data
The satellite signal is received by the antenna 11, and immediately thereafter, is subjected to low-noise amplification by the low-noise amplifier 12 so that the RF (R
adio Frequency) signal and supplied to one input terminal of the IF converter 13. The other input terminal of the IF converter 13 is supplied with a first local signal obtained by multiplying a local oscillation signal having a GPS center frequency generated by a local oscillator 14 by a multiplier 15. Then, the IF converter 13 performs frequency conversion to an IF (intermediate frequency) band by multiplying the RF signal by the first local signal.

The IF signal is a visible GPS satellite signal that can be received at that time, and a plurality of predetermined amplitudes are spread in accordance with a PN (pseudo noise) code for identifying each GPS satellite. This IF signal is supplied to the baseband units 101 to 10N, respectively.

In the baseband processing unit 101, the input IF signal is supplied to one input terminal of the PN code canceller 16. The other input terminal of the PN code canceler 16 is supplied with a PN code oscillation signal generated by the PN code generator 17 and assigned to the own device. Then, the PN code release unit 16 outputs the P signal to the IF signal.
Despread by multiplying the N code oscillation signal,
Each GPS satellite signal assigned to the own device can be extracted. Therefore, the baseband processing units 101 to 10
The number N is the number of channels of the GPS receiver and is the maximum number of receivable satellites.

The GPS satellite signal extracted by the PN code remover 16 is supplied to a phase comparator 18 where N
By comparing the phase with a second local signal having a GPS center frequency generated by a CO (Numerically Controlled Oscillator) 19, the phase difference component is extracted as a received signal. This reception signal is transmitted to the reception control unit 2
00 is supplied.

The reception control unit 200 calculates, in real time, a PN code phase set value to be set in the PN code generator 17 and a carrier phase set value to be set in the NCO 19 based on the input received signal. A certain PN code phase setting signal and a carrier phase setting signal are supplied to a PN code generator 17 and an NCO 19, respectively, so as to perform a phase tracking for signals input to a PN code canceler 16 and a phase comparator 18, respectively. In addition, the reception control unit 200 generates pseudo-range data with the GPS satellites calculated based on the input received signal, carrier wave phase data, and visible GPS obtained by demodulating the received signal.
The observation data including the ephemeris data of the satellite is output to the error component removing unit 301. This process is performed independently for each GPS satellite signal in each of the baseband units 101 to 10N. Note that the ephemeris data includes the position data of the GPS satellites, the orbit change rate, and the like.

The error component removing unit 301 removes the error component from the input observation data based on the separately provided error estimation value, and outputs the observation data from which the error component has been removed to the positioning calculation unit 302. Also, the error component removing unit 301
Includes a low-pass filter that removes an error component outside a predetermined signal band from observation data.

The positioning operation unit 302 executes positioning operation processing based on the observation data for each of the baseband processing units 101 to 10N to obtain positioning data indicating the position of the own device. The positioning data obtained here is, as shown in FIG. 2, three-dimensional information (X, Y, and the like) representing the position of the GPS receiver viewed from, for example, four GPS satellites 401 to 404.
Z) and its change (speed) (dX / dt, dY
/ Dt, dZ / dt).

In FIG. 2, the GPS receiver is
Position information of the X component in the own device is obtained using the GPS satellite 401, position information of the Y component in the own device is obtained using the GPS satellite 402, and Z component in the own device is used using the GPS satellite 403. Is obtained.
Further, the operation time information of the own device can be obtained using the GPS satellite 404.

The positioning data obtained by the positioning calculator 302 is output to the error component estimator 303. The error component estimating unit 303 obtains an error estimated value that maximizes the estimated probability of the error component given to the observation data using the input positioning data, and sends the obtained error estimated value to the error component removing unit 301. give feedback. Further, the error component estimating unit 303 stops the error estimation value calculation process when the positioning data obtained by the positioning calculation unit 302 converges to a certain value. The error estimation values obtained here include multipath, SA (selectivity), Sagnac as caused by orbital changes in GPS satellites, ionosphere, troposphere, reception clock, and noise. That is, it is presumed that the positioning data Robs obtained by the positioning calculation unit 302 has an error component shown by the following equation added to the true positioning data Rtrue.

Robs = Rtrue + dSA + dsagnac + dion +
dtrpc + dmulti + dclock + dnoise, where dSA is an error estimate by SA and dsagnac is Sag
An error estimate by nac, dion is an error estimate by the ionosphere, dtrpc is an error estimate by the troposphere, dmulti is an error estimate by multipath, dclock is an error estimate by the received clock, and dnoise is a noise component.

Next, the operation of the GPS receiver configured as described above will be described. (1) Initial setting process First, a GPS satellite signal is received by a GPS receiving device for a predetermined time or more, and rough positioning is performed by a positioning calculation unit 302.
The positioning data is calculated by an averaging operation. At this time, the positioning calculation unit 302 also calculates a clock offset and a clock drift by an averaging operation.

(2) Extraction of SA Component The error component estimator 303 calculates geometric distance data from the positioning data obtained in (1) and the satellite position data obtained from the ephemeris data, and includes them in the observation data. This geometric distance data is subtracted from the pseudo distance data with the GPS satellite. Then, from this residual, Sagnac
Is subtracted.

Further, in order to reduce an error component due to the ionosphere, an estimated error value dion due to the ionosphere is obtained as shown in the following equation. Dion = {Robs- (λ / 2π) φ} / 2λ: wavelength φ: phase The error estimate dion is subtracted from the residual.

With the above operation, the SA component, the error component including the effect of the multipath, and the noise component are extracted. Generally, since the period of the SA component is predetermined, the noise component can be removed by the error component removing unit 301 by using a low-pass filter that cuts the SA component and below. In this state, the SA component and the error estimated value due to the multipath mainly remain.

(3) Repetition As shown in FIG. 3, the error component removing unit 301 subtracts the residual for each GPS satellite obtained in the above process (2) from the pseudorange data included in the observation data, The positioning calculation unit 302 performs positioning calculation. Such processing is repeatedly performed, and the error component estimating unit 303 monitors a change in the positioning data. Thereafter, when the positioning data converges to a certain value in the error component estimation unit 303, the error estimation value calculation processing is stopped.

According to the above-described processing procedure, the positioning accuracy can be improved with an inexpensive GPS receiver that receives a GPS satellite signal of only one frequency.

As described above, according to the above embodiment, satellite signals from four GPS satellites are received, and observation data including ephemeris data of the GPS satellites and pseudorange data with the GPS satellites are received from the received signals. Control unit 200
After the error component is removed from the observation data for these four GPS satellites based on the error estimation value separately provided by the error component removal unit 301, the position of the own device is determined by the positioning calculation unit 302. Using the measured positioning data obtained by the error component estimating unit 303, an error estimated value due to multipath, SA, Sagnac, ionosphere, troposphere, received clock, and noise is obtained, and extracted again by the error component removing unit 301. The error component based on the obtained error estimation value is repeatedly subtracted from the obtained observation data. That is, the error component calculation process and the error component removal process are repeatedly executed until the positioning data converges to the predetermined value by the error component estimation unit 303. Of these, the error component due to noise is removed by the error component removal unit 301. , And is removed by a low-pass filter that removes error components below the SA signal band.

For this reason, by repeatedly executing the error component calculation process and the error component removal process by feedback, only one frequency needs to be received.
Since there is no need to process two frequencies, the processing capability of the processor can be reduced, so that the positioning accuracy can be improved while reducing the size and weight of the device and reducing the price.

In the above embodiment, the error component calculation process and the error component removal process are realized by a hardware configuration, but may be realized by a software configuration. Further, in the above-described embodiment, the description has been given of a GPS. However, the present invention can be applied to a position measurement system using other positioning satellites. further,
In the above embodiment, an example in which four GPS satellites are used has been described. However, if four or more visible GPS satellites are used, highly reliable positioning can be performed.

In addition, the configuration of the GPS receiver, the procedure for calculating the error estimation value, the type of the error estimation value, and the like can be variously modified without departing from the gist of the present invention.

[0035]

As described in detail above, according to the present invention,
It is possible to provide a positioning receiving device capable of improving positioning accuracy while reducing the size and weight of the device, and a positioning information processing method applied to the device.

[Brief description of the drawings]

FIG. 1 is a circuit block diagram showing an embodiment of a GPS receiver according to the present invention.

FIG. 2 shows a GPS receiver and a plurality of G's in the embodiment.
The figure which shows the positional relationship with a PS satellite, and a positioning concept.

FIG. 3 is a characteristic diagram showing an example of a temporal change between positioning data and an error component used in the embodiment.

[Explanation of symbols]

 Reference Signs List 11 antenna, 12 low-noise amplifier, 13 IF converter, 14 local oscillator, 15 multiplier, 16 PN code canceller, 17 PN code generator, 18 phase comparator, 19 NCO (Numerically Controlled Oscillator), 101 to 10N: baseband processing unit, 200: reception control unit, 301: error component removing unit, 302: positioning operation unit, 303: error component estimating unit, 401 to 404: GPS satellites.

Claims (10)

[Claims] 1. A positioning receiving apparatus for measuring the position of the own apparatus using a positioning satellite, wherein receiving means for receiving, from a plurality of positioning satellites, a satellite signal including position information and transmission time information of the positioning satellite. And observation information extraction means for extracting observation information including position information of the positioning satellite and distance information from the positioning satellite from a reception signal obtained by the reception means; and obtaining the observation information based on the given error estimation information. Error component removing means for removing an error component from the observation information extracted by the extracting means; positioning calculating means for obtaining the position of the own apparatus from the observation information obtained by the error component removing means; Error information estimating means for inputting positioning information, obtaining error estimating information for estimating the error component estimating probability given to the received signal to be maximum, and providing the error estimating information to the error component removing means; Positioning receiving apparatus characterized by comprising comprises. 2. The positioning receiver according to claim 1, wherein said error component removing means includes a filter for removing an error component outside a predetermined signal band from said observation information. 3. The error component estimating means, when the positioning information obtained by the positioning calculation means converges to a predetermined value,
2. The positioning receiver according to claim 1, wherein error estimation information calculation processing for said error component removing means is stopped. 4. The positioning receiving apparatus according to claim 1, wherein the error component estimating means inputs the positioning information and obtains error estimation information based on multipath and selection availability. 5. The error component estimating means inputs the positioning information, and changes an orbit, an ionosphere,
The positioning receiver according to claim 1, wherein error estimation information based on a troposphere, a reception clock, and noise is obtained. 6. A positioning information processing method applied to a positioning receiving device that measures the position of its own device using a positioning satellite, comprising: transmitting position information and transmission time information of the positioning satellite from a plurality of positioning satellites; Receiving the satellite signal including the position information of the positioning satellite and the observation information including the distance information from the positioning satellite from the received signal.Based on the error estimation information provided, an error component is extracted from the extracted observation information. Is obtained, the position of the own apparatus is obtained from the observation information from which the error component has been removed, and the obtained positioning information is input, and the error estimation information that maximizes the estimation probability of the error component given to the received signal is obtained. A positioning information processing method characterized in that an error component given to observation information is obtained and used for removing an error component. 7. The positioning information processing method according to claim 6, wherein a filter for removing an error component outside a predetermined signal band from observation information is used for removing the error component. 8. The positioning information processing method according to claim 6, wherein the calculation processing of the error estimation information is stopped when the obtained positioning information converges to a predetermined value. 9. The positioning information processing method according to claim 6, wherein the error estimation information is error estimation information based on multipath and selection availability. 10. The positioning information processing method according to claim 6, wherein the error estimation information is error estimation information based on the rotation of the earth, the ionosphere, the troposphere, a reception clock, and noise.