JP2008281551A - Present position locating method and program, storage medium, positioning device, and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the amount of calculation to be required for calculating a located position, when positioning calculation is performed for each of a plurality of satellite sets in one-time positioning. <P>SOLUTION: Estimation calculations for calculating an estimated present position are performed twice corresponding to each satellite set. The estimated present position calculated by the second estimation calculations is determined to be a present position candidate corresponding to the satellite set. On this occasion, in the first estimation calculations corresponding to the first satellite set, the calculated satellite position and estimated pseudo-range of each GPS satellite are stored in caches. In the second estimation calculations, the satellite position of each GPS satellite is read and acquired from the cache. In the first estimation calculations corresponding to the second or subsequent satellite set, the satellite position and the estimated pseudo-range of each GPS satellite are read and acquired from the caches, and the satellite position and the estimated pseudo-range of the GPS satellite of which the satellite position and the estimated pseudo-range have not been stored in the cashes are calculated and stored in the caches. In the second estimation calculations, the satellite position of each GPS satellite is read and acquired from the cache. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a current position positioning method, a program, a storage medium, a positioning device, and an electronic apparatus.

  As a positioning system using an artificial satellite, a GPS (Global Positioning System) is widely known and used in a car navigation device or the like. In GPS, a GPS satellite signal is transmitted from each of a plurality of GPS satellites orbiting the earth orbit, and the GPS receiver calculates (positions) the current position based on the received GPS satellite signal.

  The calculation of the position of the GPS receiver is generally performed as follows. That is, a satellite set that is a combination of four or more GPS satellites is generated from the captured GPS satellite signals, and a positioning calculation is performed for each satellite set to calculate the current position. Then, of the calculated current positions of each satellite set, the one that seems to have the highest accuracy is selected based on an index such as PDOP (Position Dilution of Precision), for example, and is used as the current positioning result.

In addition, when calculating the current position for each of a plurality of satellite sets in this way, in the previous stage of positioning, a “positioning accuracy prediction decrease rate” is calculated for each satellite set, and based on this positioning accuracy prediction decrease rate, A method has been proposed in which a satellite set that is considered to have the best positioning accuracy (that is, the rate of decrease is the smallest) is first acquired for positioning. The “positioning accuracy prediction decrease rate” is an index defined by the geometrical arrangement in the sky of the GPS satellite, and is set such that the decrease rate decreases as the arrangement spreads larger. This is because the positioning accuracy tends to improve as the spread of the GPS satellites increases. This method is particularly effective as a method for performing accurate positioning when time has elapsed since the previous positioning (see, for example, Patent Document 1).
JP 2006-90839 A

  By the way, in the method of calculating the current position by performing positioning calculation for each of a plurality of satellite sets of GPS satellites, there is a problem that it takes time for positioning. For example, simply, the time required for positioning increases in proportion to the number of satellite sets. In recent years, portable electronic devices such as portable telephones and wristwatches have been equipped with a GPS function. Since portable GPS receivers are usually used while moving, for example, at intervals of one second. As described above, it is necessary to measure the current position within a predetermined time limit.

  The present invention has been made to solve the above-described problem, and has an object to shorten the amount of calculation required for calculating a positioning position when performing positioning calculation for each of a plurality of satellite sets in one positioning. Yes.

  A first invention for solving the above problem is a current position positioning method for receiving a satellite signal transmitted from a positioning satellite and repeatedly executing a positioning calculation of the current position based on the received satellite signal. A satellite set selection step for selecting a satellite set, which is a combination of satellites used for the current positioning calculation based on the received satellite signal, and, for each of the selected satellite sets, each satellite included in the satellite set. A current position calculation step for each satellite set that calculates current position candidates using satellite signals, and a current position candidate is selected from the current position candidates of each of the calculated satellite sets, and the current positioning position A current position determining step for each satellite set, the temporary current position setting step for setting a temporary current position, and the position of each satellite. The position of each satellite in the satellite set is read out and acquired from the satellite position storage unit to be stored, and the satellites that are not stored are calculated and acquired based on the received satellite signals of the satellites. A satellite position acquisition step for storing in the satellite position storage unit, and an estimated pseudo distance acquisition step for acquiring an estimated pseudo distance that is a pseudo distance between the set temporary current position and each of the satellites. , Repeatedly executing a predetermined estimation operation using the set temporary current position, the acquired position of each satellite of the satellite set, and the acquired estimated pseudorange as an initial value. This is a current position positioning method which is a step of calculating current position candidates by a set.

  According to a sixth aspect of the present invention, there is provided a positioning device that receives a satellite signal transmitted from a positioning satellite and repeatedly executes a positioning calculation of a current position based on the received satellite signal, based on the received satellite signal. The satellite set selection unit for selecting a satellite set that is a combination of the satellites used for the positioning calculation of this time, and for each selected satellite set, the current position candidate is obtained using the satellite signal of each satellite included in the satellite set. A current position calculation unit for each satellite set to be calculated, and a current position determination unit for selecting a current position candidate from the calculated current position candidates for each satellite set and determining the current position position as a current positioning position; The satellite set current position calculation unit includes: a temporary current position setting unit that sets a temporary current position; and a satellite position storage unit that stores a position of each satellite. Read A satellite position acquisition unit that calculates and acquires the position of the satellite based on the received satellite signal of the satellite, and stores the satellite position in the satellite position storage unit. An estimated pseudo distance acquisition unit that acquires an estimated pseudo distance that is a pseudo distance between the set temporary current position and each of the satellites, and sets the set temporary current position and each of the satellite sets. The positioning device calculates a current position candidate by the satellite set by repeatedly executing a predetermined estimation calculation using the acquired position of the satellite and the acquired estimated pseudorange as an initial value.

  According to the first or sixth invention, the current position candidate for each of the satellite sets selected based on the received satellite signal is the temporary current position, the position of each satellite in the satellite set, and the estimated pseudorange. It is calculated by repeatedly executing a predetermined estimation calculation using as an initial value. At this time, the position of each satellite is acquired by reading from the satellite position storage unit that stores the position of each satellite, and the satellites that are not stored are calculated and acquired based on the received satellite signals of the corresponding satellites. In addition, the calculated position is stored in the satellite position storage unit. By the way, although the same satellite may be included in different satellite sets, the position of each satellite is not different depending on the satellite set including the satellite. Therefore, by storing the calculated position of each satellite in the satellite position storage unit, satellites that have already been calculated are read out from the satellite position storage unit without calculating the position of the satellite. This eliminates the need to perform the same calculation a plurality of times, and reduces the amount of calculation required for calculating the positioning position.

  In addition, as another invention, a step of selecting a plurality of satellite sets that are combinations of satellites, a step of calculating a current position candidate for each of the satellite sets using satellite signals of each satellite included in the satellite set, Selecting a current position candidate alternatively from the current position candidates of each of the satellite sets and determining as a current positioning position, and further calculating a current position candidate of each of the satellite sets Reads and acquires the position of each satellite in the satellite set from the satellite position storage unit that stores the position of each satellite, and for the satellites that are not stored, the position of the satellite is determined based on the satellite signal of the satellite. Calculating and storing in the satellite position storage unit, and obtaining an estimated pseudo distance that is a pseudo distance between the temporary current position and each of the satellites of the satellite set. A current position positioning method, comprising: calculating the current position candidate by the satellite set using the temporary current position, the position of each satellite of the satellite set, and the estimated pseudorange as initial values. It may be configured.

  A second invention is a current position positioning method according to the first invention, wherein the provisional current position setting step includes the previous positioning in the first estimation calculation among the predetermined estimation calculations for the satellite set. The position is set as a temporary current position, and the estimation current position calculated in the previous estimation calculation is set as the temporary current position in the second and subsequent estimation calculations; Is an estimated pseudo-range storage unit that stores an estimated pseudo-distance associated with each of the satellites during the initial estimation computation of the predetermined estimation computation for the satellite set, The pseudo distance is read and acquired, and for the satellites that are not stored, the estimated pseudo distance is calculated and acquired from the acquired position of the satellite and the set temporary current position, and the estimated In the first-time step stored in the similar distance storage unit and the second and subsequent estimation calculations of the predetermined estimation calculation for the satellite set, the set temporary current position and the acquired satellite set And a second and subsequent steps for calculating and obtaining an estimated pseudorange for each satellite from the position of each satellite.

  Further, a seventh invention is the positioning device of the sixth invention, wherein the temporary current position setting unit performs the previous positioning in the first estimation calculation among the predetermined estimation calculations for the satellite set. The position is set as a tentative current position, and in the second and subsequent estimation calculations, the estimated current position calculated in the previous estimation calculation is set as a tentative current position. At the time of the first estimation calculation among the predetermined estimation calculations for the satellite set, an estimated pseudo distance related to each satellite in the satellite set is calculated from an estimated pseudo distance storage unit storing the estimated pseudo distance related to each satellite. For the satellites that are read and acquired, and for the satellites that are not stored, the estimated pseudo distance is calculated and acquired from the acquired position of the satellite and the set temporary current position, and stored in the estimated pseudo distance storage unit. For the first time In the second and subsequent estimation calculations of the predetermined estimation calculation for the satellite set, the acquisition unit and the acquired temporary current position and the acquired position of each satellite of the satellite set It is a positioning apparatus which has the acquisition part for the 2nd time and later which calculates and acquires the estimated pseudorange concerning each satellite.

  According to the second or seventh invention, among the predetermined estimation calculations for each satellite set, in the first estimation calculation, the previous positioning position is set as a temporary current position, and the estimated pseudorange of each satellite is set. Is obtained by reading from an estimated pseudorange storage unit that stores an estimated pseudorange for each satellite, and for satellites that are not stored, obtained by calculating from the position of the satellite and the temporary current position. The calculated estimated pseudo distance is stored in the estimated pseudo distance storage unit. Then, in the second and subsequent estimation calculations, the estimated current position calculated in the previous estimation calculation is set as a temporary current position, and the estimated pseudo-range for each satellite is the position of the satellite and the temporary current position. It is obtained from the calculation. By the way, the estimated pseudorange of each satellite is not different depending on the satellite set including the satellite as long as the position of the satellite and the temporary current position are the same. That is, in the first estimation calculation in which the temporary current position is the same (previous positioning position) for any satellite set, the estimated pseudorange of each satellite is the same regardless of the satellite set including the satellite. For this reason, for the first estimation operation, the estimated pseudorange of each satellite is stored, so that the estimated pseudorange of the satellite is not calculated for the satellite for which the estimated pseudorange has already been calculated. Thus, it is possible to read out and acquire from the estimated pseudo-distance storage unit, thereby eliminating the need to perform the same calculation a plurality of times and further reducing the amount of calculation required for calculating the positioning position.

  Further, as a fourth invention, the above-described current position positioning method is applied to a computer built in a positioning device that receives a satellite signal transmitted from a positioning satellite and measures the current position based on the received satellite signal. It is good also as comprising the program for performing.

  As a fifth invention, a computer-readable storage medium storing the program of the fourth invention may be configured.

  Here, the storage medium is a storage medium such as a hard disk, a CD-ROM, a DVD, a memory card, or an IC memory that can read stored information. Therefore, according to the fifth aspect, it is possible to obtain the same operational effects as the fourth aspect by causing the computer to read the information stored in the storage medium and executing the arithmetic processing.

  As an eighth aspect of the invention, an electronic apparatus including the positioning device described above may be configured.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In the following description, a case where an electronic device including the positioning device of the present invention is applied to a mobile phone will be described. However, an applicable embodiment of the present invention is not limited to this.

  FIG. 1 is a block diagram showing the internal configuration of the mobile phone 1 of the present embodiment. According to FIG. 1, the mobile phone 1 includes a GPS antenna 10, a GPS receiving unit 20 that is a positioning device, a host CPU (Central Processing Unit) 40, an operation unit 41, a display unit 42, and a ROM (Read Only). Memory) 43, RAM (Random Access Memory) 44, mobile phone antenna 50, and mobile phone wireless communication circuit unit 60.

  The GPS antenna 10 is an antenna that receives an RF signal including a GPS satellite signal transmitted from a GPS satellite, and outputs the received RF signal.

  The GPS receiving unit 20 captures and extracts a GPS satellite signal from the RF signal received by the GPS antenna 10, and performs a positioning calculation based on a navigation message or the like extracted from the GPS satellite signal to calculate a current position. The GPS receiving unit 20 includes an RF (Radio Frequency) receiving circuit unit 21, a TCXO (Temperature Controlled Oscillators) 22, and a baseband processing circuit unit 30. The RF receiving circuit unit 21 and the baseband processing circuit unit 30 can be manufactured as separate LSIs (Large Scale Integration) or as a single chip.

  The TCXO 22 is a temperature compensated crystal oscillator, and generates and outputs an oscillation signal having a predetermined oscillation frequency.

  The RF receiving circuit unit 21 multiplies the RF signal input from the GPS antenna 10 by a signal obtained by dividing or multiplying the oscillation signal input from the TCXO 22, thereby multiplying the RF signal by an intermediate frequency signal (hereinafter “ The signal is down-converted to an IF (Intermediate Frequency) signal), the IF signal is amplified, etc., converted to a digital signal by an A / D converter, and output.

  The baseband processing circuit unit 30 captures and tracks a GPS satellite signal from the IF signal input from the RF receiving circuit unit 21, decodes the data, and based on a navigation message, time information, etc. It is a circuit part which performs calculation calculation of this, positioning calculation, etc.

  Specifically, the GPS satellite signal is first captured based on the input IF signal. The acquisition of the GPS satellite signal is a process of extracting the GPS satellite signal from the IF signal, and performs a correlation process on the IF signal. Specifically, a coherent process for calculating the correlation between the IF signal and the pseudo-generated replica C / A code (code replica) using an FFT operation is performed, and a correlation value as a result of the coherent process is calculated. Incoherent processing is performed to calculate a correlation integrated value by integration. Thereby, the phase of the C / A code and the carrier frequency included in the GPS satellite signal is obtained.

  If the GPS satellite signal is acquired, then the acquired GPS satellite signal is tracked. GPS signal tracking is a process of performing synchronization holding of a plurality of captured GPS satellite signals in parallel. For example, a cold loop that is realized by a delay lock loop (DLL) and tracks the phase of a C / A code, for example, A carrier loop that is implemented by a phase lock loop (PLL) and tracks the phase of the carrier frequency is performed. Then, the tracked GPS satellite signal data is decoded to extract a navigation message, and a pseudo-range calculation, a positioning calculation, and the like are performed to determine the current position.

  The baseband processing circuit unit 30 includes a CPU 31, a ROM 32, and a RAM 33, and includes various circuits such as a replica C / A code generation circuit, a correlation calculation circuit, and a data decoding circuit.

  The CPU 31 comprehensively controls each unit of the baseband processing circuit unit 30 and each unit of the RF receiving circuit unit 21 and performs various arithmetic processes including a baseband process described later.

  In the baseband processing, the CPU 31 calculates a pseudo distance to each captured GPS satellite based on the orbit information and time information of each GPS satellite included in the navigation message decoded from the captured / tracked GPS satellite signal. The current position is calculated by performing positioning calculation based on the pseudo distance.

FIG. 2 is a diagram for explaining the outline of the current position calculation (positioning) by the CPU 31. First, the CPU 31 generates a “satellite set” that is a combination of four or more GPS satellites from the captured GPS satellite signals. For example, if eight GPS satellites signals captured, satellite set 163 pieces _{(= 8 C 8 + 8 C} 7 + 8 C 6 + 8 C 5 + 8 C 4) is generated. Next, the current position candidate P of the own aircraft is calculated by performing positioning calculation using the least square method for each generated satellite set.

  Then, one of the current position candidates of each of these satellite sets is selected according to a predetermined evaluation criterion, for example, and determined as the current positioning position. Here, as an evaluation criterion, for example, a known method such as a position accuracy degradation index PDOP (Position Dilution of Precision) based on the geometric arrangement of GPS satellites of the corresponding satellite set or a method based on the signal strength of each GPS satellite signal It is realized by. The determined positioning position is output to the host CPU 40 at the subsequent stage.

  FIG. 3 is a diagram for explaining in detail the calculation of the positioning position by the CPU 31, and shows one positioning. In the present embodiment, for each satellite set, an estimation calculation for calculating the current position (estimated current position) of the own aircraft is performed twice using the least square method. Then, the estimated current position calculated by the second estimation calculation is set as a current position candidate for the corresponding satellite set. Further, the calculation method of the current position candidate P of each satellite set is different between the first satellite set and the second and subsequent satellite sets.

  First, the first satellite set will be described. Here, the first satellite set is a satellite set “A” including four GPS satellites # 1 to # 4. In the first estimation calculation, the previous positioning position or the predetermined initial position is set as the temporary current position of the own device. For each GPS satellite of the target satellite set, the position (satellite position) of the GPS satellite is calculated and acquired based on the GPS satellite signal of the GPS satellite, and the satellite position of each GPS satellite is calculated Save to cache. That is, the satellite positions P1 to P4 of the GPS satellites # 1 to # 4 are calculated and stored in the satellite position cache. Next, for each GPS satellite in the target satellite set, a pseudo distance (estimated pseudo distance) to the temporary current position of the own aircraft is calculated, and the calculated estimated pseudo distance of each GPS satellite is stored in the estimated pseudo distance cache. To do. That is, the estimated pseudoranges L1 to L4 of the GPS satellites # 1 to # 4 are calculated and stored in the estimated pseudorange cache. Then, by performing an estimation calculation using the least square method with these temporary current positions and the satellite positions and estimated pseudoranges of each GPS satellite of the target satellite set as initial values, the current position (estimated) Current position) is calculated.

  Subsequently, a second estimation calculation is performed. In the second estimation calculation, the estimated current position calculated in the first estimation calculation performed immediately before is set as the temporary current position of the own device. Further, the satellite position of each GPS satellite in the target satellite set is read out from the satellite position cache and acquired. That is, the satellite positions P1 to P4 of the GPS satellites # 1 to # 4 are read out and acquired from the satellite position cache. Next, an estimated pseudorange is calculated and acquired for each GPS satellite of the target satellite set. That is, the estimated pseudoranges of the GPS satellites # 1 to # 4 are calculated. Since the temporary current position in the second estimation calculation is different from the temporary current position in the first estimation calculation, all the estimated pseudo distances are calculated and acquired. Subsequently, an estimation calculation for calculating the estimated current position of the own aircraft is performed using the least square method using the temporary current position, the satellite position of each GPS satellite, and the estimated pseudorange as initial values. Then, the estimated current position calculated by the second estimation calculation is set as a current position candidate for the target satellite set (first satellite set “A”).

  Next, the second satellite set will be described. Here, the second satellite set is a satellite set “B” made up of four GPS satellites # 1 to # 3 and # 5. In the first positioning calculation, similarly to the first satellite set, the previous positioning position or the predetermined initial position is set as the temporary current position of the own aircraft. In addition, the satellite position of each GPS satellite of the target satellite set is acquired. Specifically, among GPS satellites, for GPS satellites whose satellite positions are stored in the satellite position cache, the satellite positions are acquired from the satellite position cache, and for GPS satellites that are not stored, The satellite position is calculated and acquired based on the GPS satellite signal, and the calculated satellite position is stored in the satellite position cache. That is, the satellite positions P1 to P3 of the satellites # 1 to # 3 are read and acquired from the satellite position cache, and the satellite position P5 of the GPS satellite # 5 is calculated and stored in the satellite position cache. That is, the satellite position cache stores the satellite positions P1 to P5 of the satellites # 1 to # 5.

  Further, the estimated pseudorange of each GPS satellite of the target satellite set is acquired. Specifically, among GPS satellites, for GPS satellites whose estimated pseudoranges are stored in the estimated pseudorange cache, the estimated pseudoranges are acquired from the estimated pseudorange cache, and for GPS satellites that are not stored, The estimated pseudo distance is calculated and acquired, and the calculated estimated pseudo distance is stored in the estimated pseudo distance cache. That is, the estimated pseudo distances L1 to L3 of the GPS satellites # 1 to # 3 are read out from the estimated pseudo distance cache and acquired, and the estimated pseudo distance of the GPS satellite # 5 is calculated to calculate the estimated pseudo distance. Stored in the distance cache. In other words, the estimated pseudorange cache stores the estimated pseudoranges L1 to L5 of the GPS satellites # 1 to # 5, respectively. Then, the estimated current position of the own aircraft is calculated by an estimation calculation using a least square method with the temporary current position, the satellite position of each GPS satellite, and the estimated pseudorange as initial values.

  Subsequently, in the second estimation calculation, the estimated current position calculated in the first estimation calculation performed immediately before is set as the temporary current position of the own device. In addition, the satellite position of each target GPS satellite is acquired from the satellite position cache. That is, the satellite positions P1 to P3 and P4 of the GPS satellites # 1 to # 3 and # 5 are read out and acquired from the satellite position cache. Further, the estimated pseudorange of each target GPS satellite is calculated and acquired. That is, the estimated pseudo distances L1 to L3 and L5 of the GPS satellites # 1 to # 3 and # 5 are calculated and acquired. Then, the estimated current position of the own aircraft is calculated by an estimation calculation using a least square method with the temporary current position, the satellite position of each GPS satellite, and the estimated pseudorange as initial values.

  In addition, for each of the third and subsequent satellite sets, the current candidate position is calculated in the same manner as the second satellite set. As described above, in this embodiment, in each estimation calculation, the same calculation is performed a plurality of times by reading out and acquiring the position (satellite position) and pseudorange (estimated pseudorange) of each GPS satellite stored in the cache. This is not done and the amount of calculation is reduced.

  Returning to FIG. 1, the ROM 32 is a system program for the CPU 31 to control each part of the baseband processing circuit unit 30 and the RF receiving circuit unit 21, various programs and data for realizing various processes including baseband processing, and the like. Is remembered. FIG. 4 shows an example of the configuration of the ROM 32. According to FIG. 4, the ROM 32 stores a baseband processing program 321.

  The RAM 33 is used as a work area of the CPU 31, and temporarily stores programs and data read from the ROM 32, calculation results executed by the CPU 31 according to various programs, and the like. FIG. 5 shows an example of the configuration of the RAM 33. According to FIG. 5, in the RAM 33, satellite set data 331 and least squares initial value data 332 are stored, and a satellite position cache 333, which is a data storage area, and an estimated pseudorange cache 334 are formed. The

  The satellite set data 331 is data on a satellite set generated from the captured GPS satellite signal. FIG. 6 shows an example of the data configuration of the satellite set data 331. According to FIG. 6, the satellite set data 331 stores, for each generated satellite set 331a, the GPS satellite 331b, the current position candidate 331c, and the evaluation point 331d included in the satellite set in association with each other. .

  The least square method initial value data 332 is data of an initial value used in an estimation calculation using the least square method. FIG. 7 shows an example of the data configuration of the least square method initial value data 332. According to FIG. 7, the least squares method initial value data 332 stores the temporary current position 332a of the own aircraft and the target satellite set 332b, and for each GPS satellite included in the target satellite set, The satellite ID 332c, the satellite position 332d, and the estimated pseudo distance 332e are stored in association with each other.

  The satellite position cache 333 is a data storage area (satellite position storage unit) for storing the satellite position of each GPS satellite. FIG. 8 shows an example of the data configuration of the satellite position cache 333. According to FIG. 8, in the satellite position cache 333, an area (data area) for storing the satellite position is formed for each of the 32 GPS satellites currently operated (actually operated).

  The estimated pseudo distance cache 334 is a data storage area (estimated pseudo distance storage unit) for storing the estimated pseudo distance of each GPS satellite. FIG. 9 shows an example of the data configuration of the estimated pseudorange cache 334. According to FIG. 9, the estimated pseudorange cache 334 has areas (data areas) for storing estimated pseudoranges for each of the 32 GPS satellites currently in operation.

  The host CPU 40 comprehensively controls each unit of the mobile phone 1 according to various programs such as a system program stored in the ROM 43. Specifically, the telephone function as a telephone is mainly realized, and a navigation screen in which the current position of the mobile phone 1 input from the baseband processing circuit unit 30 is plotted on a map is displayed on the display unit 42. Processing for realizing various functions including a navigation function is performed.

  The operation unit 41 is an input device including operation keys, button switches, and the like, and outputs an operation signal corresponding to an operation by a user to the host CPU 40. By operating the operation unit 41, various instructions such as a positioning start / end instruction are input. The display unit 42 is a display device configured by an LCD (Liquid Crystal Display) or the like, and displays a display screen (for example, a navigation screen or time information) based on a display signal input from the host CPU 40.

  The ROM 43 stores a system program for the host CPU 40 to control the mobile phone 1 and various programs and data for realizing a navigation function. The RAM 44 is used as a work area of the host CPU 40 and temporarily stores programs and data read from the ROM 43, data input from the operation unit 41, calculation results executed by the host CPU 40 according to various programs, and the like.

  The cellular phone antenna 50 is an antenna that transmits and receives cellular phone radio signals to and from a radio base station installed by a communication service provider of the cellular phone 1. The mobile phone radio communication circuit unit 60 is a mobile phone communication circuit unit configured by an RF conversion circuit, a baseband processing circuit, and the like, and transmits and receives radio signals under the control of the host CPU 40.

[Process flow]
FIG. 10 is a flowchart for explaining the flow of the baseband processing. This processing is realized by the CPU 31 executing the baseband processing program 321. Prior to baseband processing, an IF signal digitized through reception of an RF signal by the GPS antenna 10 and down-conversion to an IF signal by the RF reception circuit unit 21 is input to the baseband processing circuit unit 30 as needed. Suppose that it is in a state.

  According to FIG. 10, the CPU 31 first clears the satellite position cache 333 and the estimated pseudorange cache 334 (step A1). Next, a satellite set composed of four or more GPS satellites is generated based on the acquired satellite signals (step A3), and the process of loop A is performed for each of the generated satellite sets.

  In the loop A, first, the predetermined initial position or the previous positioning position is set as the temporary current position of the own machine (step A5). Then, loop B processing is performed for each GPS satellite of the target satellite set.

  In loop B, it is determined whether or not the satellite position of the target GPS satellite is stored in the satellite position cache 333. If it is stored (step A7: YES), the position information of the GPS satellite is stored in the satellite position cache. It acquires from 333 (step A9). On the other hand, if not saved (step A7: NO), the satellite position of the GPS satellite is calculated and acquired based on the GPS satellite signal of the target GPS satellite, and the calculated satellite position corresponds to the GPS satellite. In addition, it is stored in the satellite position cache 333 (step A11).

  Next, the CPU 31 determines whether or not the estimated pseudorange of the target GPS satellite is stored in the estimated pseudorange cache 334, and if it is stored (step A13: YES), the estimated pseudorange of the GPS satellite is stored. Is obtained from the estimated pseudorange cache 334 (step A15). On the other hand, if not stored (step A13: NO), the estimated pseudorange of the GPS satellite is calculated and acquired, and the calculated estimated pseudorange is associated with the GPS satellite and stored in the estimated pseudorange cache 334. (Step A17). Loop B is performed in this way. By this loop B, the satellite position and estimated pseudorange of each GPS satellite of the target satellite set are acquired.

  When the loop B for all the GPS satellites of the target satellite set is completed, the CPU 31 starts with the temporary current position of the own device, and the calculated satellite position and estimated pseudorange of each GPS satellite as the initial position. A position estimation calculation is performed to calculate the estimated current position of the own aircraft for the target satellite set by multiplication (step A19). This is the first position estimation calculation.

  Subsequently, a second position estimation calculation is performed. That is, first, the current position candidate calculated in the immediately preceding first position estimation calculation is set as the temporary current position of the own device (step A21). Next, a loop C process is performed for each GPS satellite of the target satellite set. In loop C, the satellite position of the target GPS satellite is acquired from the satellite position cache 333 (step A23), and the estimated pseudorange of the GPS satellite is calculated and acquired from the acquired satellite position and the determined temporary current position. (Step A25). Loop C is performed in this way. By loop C, the respective satellite positions and estimated pseudorange information are acquired for each GPS satellite of the target satellite set.

  When the processing of the loop C for all the GPS satellites of the target satellite set is completed, the CPU 31 sets the temporary current position of the own device and the calculated satellite positions and estimated pseudoranges of the respective GPS satellites as initial values. An estimation calculation is performed to calculate the estimated current position of the subject aircraft for the target satellite set by the least square method (step A27). This is the second estimation calculation.

  Subsequently, the calculated estimated current position is set as a current position candidate of the satellite set (step A29). Next, evaluation processing for determining the evaluation point of the calculated current position candidate for the target satellite group using PDOP or the like is performed (step A31). Then, the calculated current position candidate and the evaluation point are stored in association with the target satellite set (step A33). Loop A is performed in this way.

  When the processing of Loop A for all the satellite sets is completed, the current position candidate corresponding to the satellite set with the highest evaluation score is determined as the current positioning position among all the satellite sets (step A35). Thereafter, it is determined whether or not the positioning is to be ended. If the positioning is not to be ended (step A37: NO), the process proceeds to step A1 to perform the next positioning. If completed (step A37: YES), the baseband processing is terminated.

[Action / Effect]
Thus, according to the present embodiment, the estimation calculation for calculating the estimated current position is performed twice for each satellite set, and the estimated current position by the second estimation calculation is set as the current position candidate for the satellite set. The At this time, for the first set of satellites, the calculated satellite position of each GPS satellite is stored in the satellite position cache 333 and the estimated pseudorange is stored in the estimated pseudorange cache 334 in the first estimation calculation. In the second estimation calculation, the satellite position of each GPS satellite is read from the satellite position cache 333 and acquired. Also, for the second and subsequent satellite sets, in the first estimation calculation, the satellite position of each GPS satellite is read out from the satellite position cache 333 and the estimated pseudorange is read out from the estimated pseudorange cache 334 and stored. For GPS satellites that have not been calculated, the satellite position and the estimated pseudorange are calculated and acquired, and the calculated satellite position is stored in the satellite position cache 333 and the estimated pseudorange is stored in the estimated pseudorange cache 334. In the second estimation calculation, the satellite position of each GPS satellite is read from the satellite position cache 333 and acquired, as in the case of the first satellite set.

  By the way, although the same GPS satellite may be included in different satellite sets, the position of each GPS satellite does not differ depending on the satellite set including the GPS satellite. Therefore, by storing the calculated position of each GPS satellite in the satellite position cache 333, GPS satellites for which the satellite position has already been calculated are read from the satellite position cache 333 without calculating the satellite position. Can be obtained. Further, the estimated pseudorange of a GPS satellite does not differ depending on the satellite set including the GPS satellite as long as the position of the GPS satellite and the temporary current position are the same. That is, in the first estimation calculation for each satellite set, since the temporary current position is the previous positioning position, the estimated pseudorange of each GPS satellite is the same regardless of the satellite set including the GPS satellite. . For this reason, for the first estimation calculation, the estimated pseudorange of each GPS satellite is stored in the estimated pseudorange cache 334, so that the estimated pseudorange for the GPS satellite that has already been calculated is estimated pseudorange. It is possible to read and acquire from the estimated pseudo distance cache 334 without calculating the distance. As a result, the same calculation is not performed a plurality of times, and the amount of calculation required to calculate the positioning position can be reduced.

[Modification]
It should be noted that the application of the present invention is not limited to the above-described embodiment, and can of course be changed as appropriate without departing from the spirit of the present invention.

(A) Host CPU
For example, part or all of the processing performed by the CPU 31 of the baseband processing circuit unit 30 may be performed by the host CPU 40 in software.

(B) GPS positioning device In the above-described embodiment, the case where the GPS positioning device is applied to a mobile phone has been described. However, for example, a portable navigation device, an in-vehicle navigation device, a PDA (Personal Digital Assistants), a wristwatch, etc. The same can be applied to other electronic devices.

(C) Satellite Positioning System In the above-described embodiment, the case where GPS is used has been described, but it is needless to say that the present invention can be similarly applied to other satellite positioning systems such as GLONASS (GLObal Navigation Satellite System).

(D) Recording medium The baseband processing program 321 may be recorded on a recording medium such as a CD-ROM and installed in an electronic device such as a mobile phone.

The internal block diagram of a mobile telephone. The schematic diagram of determination of a positioning position. Explanatory drawing of calculation of the present position candidate about each satellite set. The block diagram of ROM. The block diagram of RAM. Data configuration example of satellite set data. The data structural example of the least squares method initial value data. Configuration example of satellite position cache. The structural example of an estimation pseudorange cache. The flowchart of a baseband process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mobile phone, 20 GPS receiving part, 21 RF receiving circuit part, 22 TCXO, 30 Baseband processing circuit part, 31 CPU, 32 ROM, 33 RAM, 321 Baseband processing program, 331 Satellite set data, 332 Least square method initial stage Value data, 333 Satellite position cache, 334 Estimated pseudorange cache

Claims (8)

A current position positioning method for receiving a satellite signal transmitted from a positioning satellite and repeatedly executing a positioning calculation of the current position based on the received satellite signal,
A satellite set selection step for selecting a satellite set that is a combination of the satellites used for the positioning calculation based on the received satellite signals;
For each selected satellite set, a current position calculation step for each satellite set that calculates a current position candidate using the satellite signal of each satellite included in the satellite set;
Current position determination step for selecting a current position candidate alternatively from the calculated current position candidates of each satellite set, and determining the current positioning position;
Including
The satellite position current position calculating step includes:
A provisional current position setting step for setting a provisional current position;
From the satellite position storage unit that stores the position of each satellite, the position of each satellite of the satellite set is read and acquired, and for satellites that are not stored, based on the received satellite signal of the satellite, A satellite position acquisition step of calculating and acquiring a position and storing it in the satellite position storage unit;
An estimated pseudorange acquisition step of acquiring an estimated pseudorange that is a pseudorange between the set temporary current position and each of the satellites;
And repeatedly executing a predetermined estimation operation using the set temporary current position, the acquired position of each satellite of the satellite set, and the acquired estimated pseudorange as initial values. A step of calculating current position candidates by the satellite set;
Current location method. The current position positioning method according to claim 1,
The temporary current position setting step sets the previous positioning position as a temporary current position in the first estimation calculation among the predetermined estimation calculations for the satellite set, and in the second and subsequent estimation calculations. Is a step of setting the estimated current position calculated in the previous estimation calculation as a temporary current position,
The estimated pseudo-range acquisition step includes
In the first estimation calculation of the predetermined estimation calculation for the satellite set, from the estimation pseudo-range storage unit that stores the estimation pseudo-range for each of the satellites, the estimated pseudo-distance for each satellite of the satellite set For the satellites that are not stored, the estimated pseudorange is calculated and acquired from the acquired position of the satellite and the set temporary current position, and is stored in the estimated pseudorange storage unit. The first step to store,
In the estimation calculation for the second and subsequent times of the predetermined estimation calculation for the satellite set, the satellite is related to the satellite from the set temporary current position and the acquired position of each satellite of the satellite set. A second and subsequent steps for calculating and obtaining an estimated pseudorange;
A step having
Current location method. Selecting a plurality of satellite sets that are combinations of satellites;
For each of the satellite sets, calculating a current position candidate using a satellite signal of each satellite included in the satellite set;
Selecting a current position candidate alternatively from the current position candidates of each of the satellite sets and determining the current positioning position;
In addition,
Calculating a current position candidate for each of the satellite sets,
The position of each satellite in the satellite set is read out and acquired from the satellite position storage unit that stores the position of each satellite, and the position of the satellite is calculated based on the satellite signal of the satellite for the satellites that are not stored. Storing in the satellite position storage unit,
Obtaining an estimated pseudorange that is a pseudorange between the provisional current position and each of the satellites of the satellite set;
And calculating a current position candidate by the satellite set using the temporary current position, the position of each satellite of the satellite set, and the estimated pseudorange as initial values.
Current location method.   A current position according to any one of claims 1 to 3, wherein a computer incorporated in a positioning device that receives a satellite signal transmitted from a positioning satellite and measures a current position based on the received satellite signal. Program for executing the positioning method.   A computer-readable storage medium storing the program according to claim 4. A positioning device that receives a satellite signal transmitted from a positioning satellite and repeatedly executes a positioning calculation of a current position based on the received satellite signal,
A satellite set selection unit for selecting a satellite set that is a combination of the satellites used for the positioning calculation based on the received satellite signals;
For each of the selected satellite sets, a current position calculation unit for each satellite set that calculates a current position candidate using the satellite signal of each satellite included in the satellite set;
A current position determination unit that selects a current position candidate from the current position candidates of each of the calculated satellite sets, and determines the current positioning position;
With
The current position calculation unit for each satellite group is:
A temporary current position setting unit for setting a temporary current position;
From the satellite position storage unit that stores the position of each satellite, the position of each satellite of the satellite set is read and acquired, and for satellites that are not stored, based on the received satellite signal of the satellite, A satellite position acquisition unit that calculates and acquires a position and stores it in the satellite position storage unit;
An estimated pseudorange acquisition unit that acquires an estimated pseudorange that is a pseudorange between the set temporary current position and each of the satellites;
And repeatedly executing a predetermined estimation operation using the set temporary current position, the acquired position of each satellite of the satellite set, and the acquired estimated pseudorange as initial values. To calculate the current position candidate for the satellite set,
Positioning device. The positioning device according to claim 6,
The temporary current position setting unit sets the previous positioning position as a temporary current position in the first estimation calculation among the predetermined estimation calculations for the satellite set, and performs the second and subsequent estimation calculations. Sets the estimated current position calculated in the previous estimation calculation as the temporary current position,
The estimated pseudo-range acquisition unit
In the first estimation calculation of the predetermined estimation calculation for the satellite set, from the estimation pseudo-range storage unit that stores the estimation pseudo-range for each of the satellites, the estimated pseudo-distance for each satellite of the satellite set For the satellites that are not stored, the estimated pseudo distance is calculated and acquired from the acquired position of the satellite and the set temporary current position, and is stored in the estimated pseudo distance storage unit. An initial acquisition unit to store;
In the estimation calculation for the second and subsequent times of the predetermined estimation calculation for the satellite set, the satellite is related to the satellite from the set temporary current position and the acquired position of each satellite of the satellite set. An acquisition unit for the second and subsequent times for calculating and acquiring the estimated pseudorange;
Having
Positioning device.   An electronic device comprising the positioning device according to claim 6.

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