JP2010078476A - Reliability determination method of long term prediction orbital data, positioning method, positioning device, and positioning system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a procedure for determining reliability of a long term prediction ephemeris. <P>SOLUTION: In a positioning system 1, a cellular phone 4 performs positioning operation, based on a plurality of satellite combinations determined by combining GPS satellites SV to the number or more which is necessary for positioning operation by using long term prediction ephemeris data received from a server system 3. Then, reliability of each prediction orbit of each GPS satellite SV included in the long term prediction ephemeris data is determined based on difference of each GPS satellite SV included in each satellite combination and on difference of each result of the positioning operation performed relative to each satellite combination. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a reliability determination method, a positioning method, a positioning device, and a positioning system for long-term predicted orbit data.

  As a positioning system using positioning signals, GPS (Global Positioning System) is widely known, and is used in positioning devices built in portable telephones, car navigation devices, and the like. In GPS, a positioning calculation for obtaining a three-dimensional coordinate value indicating the position of the own device and a clock error based on information such as positions of a plurality of GPS satellites and pseudo distances from each GPS satellite to the own device is performed. Measure with.

In positioning by GPS, satellite information such as the position, velocity, and moving direction of the GPS satellite is calculated based on navigation data such as almanac and ephemeris superimposed on the GPS satellite signal transmitted from the GPS satellite. Positioning calculation is performed using time information. Almanac is a powerful clue when capturing satellites, but is difficult to use for positioning calculations due to the poor accuracy of satellite information. On the other hand, since ephemeris has high accuracy of satellite information, it can be used not only as a powerful clue when capturing a satellite but also for positioning calculation. Therefore, for example, when positioning is started without holding the ephemeris, the ephemeris must be acquired from the GPS satellite signal, and the first positioning time (TTFF: Time To First Fix) increases.

Therefore, in Patent Document 1 and Patent Document 2, the server predicts a long-term predicted ephemeris (long-term predicted trajectory data) that is a long-term ephemeris such as one week in a server-client system, and sends it to a positioning device that is a client. Techniques to provide are disclosed.
US Patent Application Publication No. 2002/0188403 US Patent Application Publication No. 2005/0212700

  As a method of defining the long-term predicted ephemeris, a method of defining in a data format similar to that of a normal ephemeris can be considered. That is, a satellite orbit is approximated using Kepler's elliptical orbit model, which is one of the approximate models of satellite orbit, and long-term prediction is performed based on the value of the model equation parameter (hereinafter referred to as “satellite orbit parameter”). It is a method of defining an ephemeris. A satellite prediction calendar (predicted position data) including predicted positions obtained by predicting a future position of a positioning satellite in time series every predetermined time is provided from a predetermined commercial system. Approximate calculations using Kepler's elliptical orbit model can be performed using this satellite prediction calendar.

  However, the predicted position of the positioning satellite included in the satellite prediction calendar tends to deviate from the actual position of the positioning satellite in the future. For this reason, when generating a long-term predicted ephemeris by performing an approximate calculation using Kepler's elliptical orbit model, the satellite orbit obtained by the approximate calculation is more deviated from the actual satellite orbit as it is the future from the generation date and time. There is a possibility. Conventionally, once a long-term predicted ephemeris is generated, there is no mechanism to determine the reliability of the generated long-term predicted ephemeris (whether it is suitable for positioning). The acquired positioning device may perform positioning using a long-term prediction ephemeris with low reliability.

  The present invention has been made in view of the above-described problems, and an object thereof is to propose a method for determining the reliability of a long-term predicted ephemeris.

  A first invention for solving the above problems is a combination of a plurality of satellites in which a number of positioning satellites or more required for a positioning calculation are combined using long-term predicted orbit data in which satellite orbits of one day or more are predicted. Determining the reliability of the long-term predicted orbit data based on the positioning calculation of the plurality of satellite combinations and determining the reliability of the long-term predicted orbit data based on the result of the positioning calculation of the plurality of satellite combinations. Is the method.

  As another invention, the positioning calculation is performed based on a combination of a plurality of satellites combining a number of positioning satellites more than necessary for the positioning calculation using long-term predicted orbit data in which satellite orbits for one day or more are predicted. You may comprise the positioning apparatus provided with the positioning calculating part to perform and the determination part which determines the reliability of the said long-term prediction orbit data based on the result of the said positioning calculation of the said several satellite combination.

  According to the first invention and the like, positioning is performed based on a plurality of satellite combinations in which a number of positioning satellites or more required for positioning calculation are combined using long-term predicted orbit data in which satellite orbits for one day or more are predicted. Perform the operation. Based on the results of these positioning calculations, the reliability of the long-term predicted orbit data is determined. By comparing the results of positioning calculations for a plurality of satellite combinations using long-term predicted orbit data, the reliability of long-term predicted orbit data can be determined.

  Further, as a second invention, there is provided a reliability determination method for long-term predicted orbit data according to the first invention, wherein the positioning satellites included in the plurality of satellite combinations are different from each other and the plurality of satellite combinations are performed. You may comprise the reliability determination method of long-term prediction orbit data including determining the reliability of the prediction orbit of the positioning satellite contained in the long-term prediction orbit data based on the difference in the result of the positioning calculation.

  According to the second aspect of the invention, based on the difference between the positioning satellites included in the plurality of satellite combinations and the difference in the result of the positioning calculation performed on the plurality of satellite combinations, the positioning satellites included in the long-term predicted orbit data Determine the reliability of the satellite's predicted orbit. If there is a positioning calculation result that is significantly different from other positioning calculation results, there are positioning satellites that are not suitable for positioning in the satellite combination used when calculating the positioning calculation result. May be included. Therefore, it is preferable to determine a positioning satellite unsuitable for positioning based on the difference between positioning satellites included in a plurality of satellite combinations, and to determine that the reliability of the predicted orbit of the positioning satellite is low.

  According to a third aspect of the present invention, there is provided a method of determining reliability of long-term predicted orbit data according to the first or second aspect, wherein satellite orbit data of the positioning satellite is received from the positioning satellite; Determining the reliability of the long-term predicted orbit data based on the difference between the satellite position obtained from the orbit data and the satellite position obtained from the long-term predicted orbit data, It may be configured.

  Similarly, as a fourth invention, a long-term predicted orbit in which satellite orbit data of the positioning satellite is received from the positioning satellite and a satellite position obtained from the satellite orbit data and a satellite orbit for one day or more is predicted. A method of determining reliability of long-term predicted orbit data including determining reliability of the long-term predicted orbit data based on a difference from a satellite position obtained from data may be configured.

  According to the third or fourth aspect of the invention, satellite orbit data of the positioning satellite is received from the positioning satellite. Then, the reliability of the long-term predicted orbit data is determined based on the difference between the satellite position obtained from the satellite orbit data and the satellite position obtained from the long-term predicted orbit data. If the long-term predicted orbit data is highly reliable, the satellite position obtained from the satellite orbit data should be approximated to the satellite position obtained from the long-term predicted orbit data. Therefore, the reliability of the long-term predicted orbit data can be determined based on the difference between the satellite position obtained from the satellite orbit data and the satellite position obtained from the long-term predicted orbit data.

  According to a fifth aspect of the present invention, there is provided a method for determining reliability of long-term predicted orbit data according to the third or fourth aspect of the invention, wherein the long-term predicted orbit data includes a timepiece in which an error of a satellite clock of the positioning satellite is predicted. Prediction error data is included, and the positioning satellite transmits the satellite orbit data including clock error data of a satellite clock included in the positioning satellite, and the reliability is determined by the satellite A position obtained by adding a position error corresponding to the clock error obtained from the clock error data to the satellite position obtained from the orbit data, and a position corresponding to the clock error obtained from the clock prediction error data to the satellite position obtained from the long-term predicted orbit data. A reliability determination method for long-term predicted trajectory data, which is to determine the reliability of the long-term predicted trajectory data based on a difference from a position taking a position error into account, may be configured.

  According to the fifth aspect of the invention, the position of the satellite obtained from the satellite orbit data is added with the position error corresponding to the clock error obtained from the clock error data, and the clock prediction error data is added to the satellite position obtained from the long-term predicted orbit data. The reliability of the long-term predicted trajectory data is determined based on the difference from the position taking into account the position error corresponding to the clock error obtained from The accuracy of the reliability determination of the long-term predicted orbit data can be improved by not based on the difference in the satellite position but based on the position difference in which the position error corresponding to the clock error is added to the satellite position.

  In addition, as a sixth aspect of the invention, positioning is performed by using a combination of positioning satellites determined to be highly reliable by the reliability determination method for long-term predicted orbit data according to any of the first to fifth aspects of the invention. A method may be configured.

  According to the sixth aspect of the invention, positioning accuracy can be improved by performing positioning calculation using a combination of positioning satellites determined to have high reliability in long-term predicted orbit data.

  According to an eighth aspect of the present invention, there is provided a positioning system comprising a plurality of positioning devices and a server system that provides the positioning devices with long-term predicted orbit data that predicts satellite orbits for one or more days of positioning satellites. The plurality of positioning devices perform positioning calculation based on a combination of a plurality of satellites combining a plurality of positioning satellites necessary for positioning calculation using the long-term predicted orbit data received from the server system. A calculation unit; a determination unit that determines the reliability of the long-term predicted orbit data based on a result of the positioning calculation of the plurality of satellite combinations; and a transmission unit that transmits the determination result of the reliability to the server system; The server system includes a totaling unit that totals the reliability determination results received from the plurality of positioning devices, and the long-term prediction based on the totaling results of the totaling unit A determination unit that determines the reliability of the road data, and the providing unit for providing a reliability determined by the determination unit to the positioning device may be configured positioning system comprising a.

  According to the eighth aspect of the invention, the plurality of positioning devices perform positioning based on a plurality of satellite combinations obtained by combining a plurality of positioning satellites necessary for the positioning calculation using the long-term predicted orbit data received from the server system. Perform the operation. Then, based on the results of these positioning calculations, the reliability of the long-term predicted orbit data is determined, and the determination result is transmitted to the server system. On the other hand, the server system aggregates reliability determination results received from a plurality of positioning devices, and determines the reliability of long-term predicted orbit data based on the aggregation results. Then, the determined reliability is provided to the positioning device.

  With this configuration, the positioning device can determine the reliability of the long-term predicted orbit data acquired from the server system. In addition, the server system can determine the reliability of long-term predicted orbit data by aggregating the reliability judgment results of long-term predicted orbit data received from multiple positioning devices. Can be provided to the positioning device.

  Hereinafter, an example of an embodiment suitable for the present invention will be described with reference to the drawings. However, embodiments to which the present invention can be applied are not limited to this.

1. System Configuration FIG. 1 is a diagram showing a schematic configuration of a positioning system 1 in the present embodiment. The positioning system 1 includes an external system 2, a server system 3, a plurality of mobile phones 4, and a plurality of GPS satellites SV (SV1, SV2, SV3, SV4,...). In addition, since the mobile phone 4 and the GPS satellite SV can perform positioning after the data necessary for the mobile phone 4 is acquired from the server system 3, one positioning is performed by the mobile phone 4 and the GPS satellite SV. It can also be said that the system is configured. Further, as a system on the ground side, the server system 3 and the mobile phone 4 can be called a positioning system.

  The external system 2 is a known system that periodically receives a satellite signal from the GPS satellite SV, generates a satellite prediction calendar based on navigation data included in the satellite signal, and provides it to the server system 3. The satellite prediction calendar provided by the external system 2 includes, for each GPS satellite SV, a predicted position for which a future position is predicted and a clock prediction error for which an error of an atomic clock mounted on the GPS satellite SV is predicted every predetermined time (for example, Discontinuous data arranged in time series every 15 minutes). The external system 2 corresponds to, for example, a computer system of a private or public organization that provides the satellite forecast calendar.

  The server system 3 acquires the satellite prediction calendar from the external system 2 and uses the acquired satellite prediction calendar to predict the ephemeris of all the GPS satellites SV, which is at least one day or longer, for example, one week. This is a system including a server that generates and provides a period effective ephemeris (hereinafter referred to as “long-term predicted ephemeris (long-term predicted orbit data)” in the present embodiment).

  The mobile phone 4 is an electronic device for a user to send and receive calls and mails. The mobile phone 4 has a function for measuring a position (positioning function) in addition to the original functions as a mobile phone such as sending and receiving calls and emails. A positioning device for realizing is provided. The mobile phone 4 transmits a long-term predicted ephemeris request signal to the server system 3 and receives the long-term predicted ephemeris from the server system 3 in accordance with a user operation. Then, the GPS satellite SV is captured using the received long-term predicted ephemeris, and positioning is performed by executing positioning calculation based on the GPS satellite signal.

2. Server system 2-1. Functional Configuration FIG. 2 is a block diagram showing a functional configuration of the server system 3. The server system 3 includes a CPU (Central Processing Unit) 310, an operation unit 320, a communication unit 330, a ROM (Read Only Memory) 340, a hard disk 350, and a RAM (Random Access Memory) 360. A computer system connected by a bus 370.

  The CPU 310 is a processor that comprehensively controls each unit of the server system 3 according to a system program or the like stored in the ROM 340. In the present embodiment, the CPU 310 performs a process of providing the long-term predicted ephemeris to the mobile phone 4 according to the long-term predicted ephemeris providing program 341 stored in the ROM 340.

  The operation unit 320 is an input device that receives an operation instruction from an administrator of the server system 3 and outputs a signal corresponding to the operation to the CPU 310. This function is realized by, for example, a keyboard, a button, a mouse, or the like.

  The communication unit 330 is a communication device for exchanging various data used in the system with the external system 2 and the mobile phone 4 via a communication network such as the Internet.

  The ROM 340 is a read-only nonvolatile storage device, and generates a system program for the CPU 310 to control the server system 3, a program for providing the long-term predicted ephemeris to the mobile phone 4, and a long-term predicted ephemeris. Various programs such as the above programs and various data are stored.

  The hard disk 350 is a storage device that reads and writes data using a magnetic head or the like, and stores programs, data, and the like for realizing various functions of the server system 3, similar to the ROM 340.

  The RAM 360 is a readable / writable volatile storage device, and a work area for temporarily storing a system program executed by the CPU 310, a long-term prediction ephemeris providing program, various processing programs, data being processed in various processing, processing results, and the like. Is forming.

2-2. Data Configuration FIG. 3 is a diagram illustrating an example of data stored in the ROM 340. The ROM 340 stores a long-term predicted ephemeris providing program 341 read by the CPU 310 and executed as a long-term predicted ephemeris providing process (see FIG. 11). Further, the long-term predicted ephemeris providing program 341 includes a long-term predicted ephemeris generation program 3411 executed as a long-term predicted ephemeris generation process (see FIGS. 12 and 13) as a subroutine.

  The long-term predicted ephemeris providing process is generated when the CPU 310 periodically performs the process of generating the long-term predicted ephemeris data 357 and receives a request signal for the long-term predicted ephemeris data 357 from the mobile phone 4. This is processing for transmitting the long-term predicted ephemeris data 357 to the requesting mobile phone 4. The long-term predicted ephemeris providing process will be described later in detail using a flowchart.

  The long-term predicted ephemeris generation process is a process in which the CPU 310 generates long-term predicted ephemeris data 357. In the present embodiment, the CPU 310 generates long-term predicted ephemeris data 357 once every 4 hours. Specifically, a period up to one week later is set as a generation target period based on the generation date and time of the long-term predicted ephemeris data 357, and the generation target period is a plurality of periods for approximating and modeling satellite orbits (hereinafter referred to as “prediction”). This is referred to as the “target period”. In the present embodiment, the length of the prediction target period is uniformly 6 hours. That is, the generation target period of one week is divided into 28 prediction target periods every 6 hours.

  After that, out of the predicted positions included in the satellite prediction calendar 351 acquired from the external system 2, the predicted positions included in each prediction target period are extracted. Then, a Kepler satellite orbit model formula (hereinafter also referred to as “approximate model”) that minimizes the sum of squares of the distances from all the extracted predicted positions is obtained for each prediction target period. The parameters of the approximate model equation of the satellite orbit obtained at this time are referred to as “satellite orbit parameters”, and the calculation for calculating the approximate model is also referred to as “approximate calculation”. The satellite orbit obtained by the approximate calculation is referred to as “predicted orbit”. The long-term predicted ephemeris generation process will also be described in detail later using a flowchart.

  FIG. 4 is a diagram illustrating an example of data stored in the hard disk 350. The hard disk 350 stores a satellite prediction calendar 351, a totaling database 353, a totaling result database 355, and long-term predicted ephemeris data 357.

  FIG. 5 is a diagram illustrating an example of a data configuration of the satellite prediction calendar 351. The satellite prediction calendar 351 is discrete data in which predicted positions and clock prediction errors for each GPS satellite SV up to one week later are stored every 15 minutes. For example, the predicted position of the GPS satellite “SV2” at “08:30 on August 8, 2008” is “(Xp32, Yp32, Zp32)”, and the prediction error of the atomic clock is “Δtp32”. The CPU 310 receives the satellite prediction calendar 351 from the external system 2 periodically (for example, once every four hours), and updates and stores it in the hard disk 350.

  FIG. 6 is a diagram illustrating an example of a data configuration of the aggregation database 353. The aggregation database 353 is a database in which aggregation data 354 (354-1, 354-2, 354-3,...) Received from the plurality of mobile phones 4 is stored.

  The tabulation data 354 includes a terminal ID 3541 that is identification information (ID) of the mobile phone 4 that generated the tabulation data 354, and a period number 3543 of the period during which the tabular data 354 was generated. In addition, reliability data 3545 in which the predicted orbit reliability and the positioning inadequate flag are stored for each GPS satellite SV is stored in association with each other.

  The terminal ID 3541 is uniquely assigned to each mobile phone 4. The period number 3543 stores 28 period numbers (first to 28th periods) when a one-week period is divided every six hours.

  The predicted trajectory reliability is a kind of index value indicating the reliability of the predicted trajectory, and is expressed in 16 levels from “0” to “15”, where “0” has the highest reliability of the predicted trajectory, and “15”. This means that the reliability of the predicted trajectory is the lowest. The predicted orbit reliability is a value corresponding to “URA index” included in the ephemeris.

  When the satellite orbit is expressed by an orbit model formula, there is a difference between the future position of the satellite calculated from the orbit model formula and the predicted position of the satellite included in the satellite prediction calendar. That is, the future position of the satellite calculated from the orbit model formula approximating the satellite orbit does not faithfully reproduce all predicted positions. The higher the reproducibility of the predicted position, the higher the reliability of the predicted trajectory.

  The positioning inappropriate flag is a flag indicating whether or not the GPS satellite SV is a satellite unsuitable for positioning (hereinafter referred to as “positioning inappropriate satellite”), and it is determined that the satellite is a positioning inappropriate satellite. In this case, “ON” is set, and in other cases, “OFF” is set. The positioning inadequate flag corresponds to “Health information” included in the ephemeris, and is a kind of reliability index value similar to the predicted orbit reliability. In the following description, the predicted trajectory reliability and the positioning inappropriateness flag are collectively referred to as “reliability parameters”.

  For example, the data for aggregation 354-1 in FIG. 6 is data generated in the “fourth period” by the mobile phone 4 with the terminal ID 3541 “T1”. In the reliability data 3545, the predicted orbit reliability of the GPS satellite “SV2” is as high as “14” (the lower the predicted orbit reliability, the higher the reliability), which is inappropriate for positioning. The flag is set to “ON”. From this, it can be seen that the GPS satellite “SV2” is determined to have low reliability in the predicted orbit, and is further determined to be a positioning inappropriate satellite.

  FIG. 7 is a diagram illustrating an example of the data configuration of the aggregation result database 355. The total result database 355 is a database in which a plurality of total result data 356 (356-1, 356-2, 356-3,...) Is stored for each GPS satellite SV.

  In addition, the aggregation result data 356 includes the number 3561 of the GPS satellite SV, the predicted orbit reliability aggregation result data 3563 that is the data of the prediction orbit reliability aggregation result, and the positioning inappropriateness that is the data of the positioning inappropriateness flag aggregation result. Flag totaling result data 3565 is stored in association with each other.

  The predicted trajectory reliability count result data 3563 has a table structure in which the first to 28th periods and the predicted trajectory reliability of “0” to “15” are associated with each other. The number of mobile phones 4 determined to be (total value of predicted orbit reliability) is stored.

  Similarly, the positioning inadequate flag count result data 3565 includes the number of mobile phones 4 that have determined that the positioning inadequate flag of the GPS satellite SV is “ON” for each of the first to 28th periods (the positioning inadequate flag ON (Total value) is stored.

  The total value of the predicted trajectory reliability and the total value of the positioning inadequate flag ON are calculated by totaling the predicted trajectory reliability and the positioning inadequate flag stored in the reliability data 3545 of each of the totaling data 354 in FIG. can do.

  FIG. 8 shows an example of the result of calculating the distance between the predicted position included in the satellite prediction calendar 351 generated by the external system 2 and the actual position of the satellite in the period as a prediction error for a period of one week. Indicates. Here, a graph in which prediction errors for one week of four GPS satellites SV1 to SV4 as representative satellites are plotted in time series, the horizontal axis indicates the number of days, and the vertical axis indicates the prediction error, respectively. As can be seen from this figure, although the degree of increase is different for the GPS satellites SV1 to SV4, the prediction error gradually increases while oscillating with the passage of time. Although the illustration of other satellites is omitted, it is known that the same tendency is observed.

  As can be seen from this result, for each GPS satellite SV, the reliability of the predicted orbit tends to be lower and the possibility of being determined as a positioning-inappropriate satellite tends to increase as the future period elapses. In fact, in the total result data 356-1 of FIG. 7, in the 28th unit period (the most future period), the total value of the predicted trajectory reliability “15” is the largest at “4850”, and the positioning inappropriate flag ON is set. The total value is also a very high value of “6940”.

  FIG. 9 is a diagram illustrating an example of the data configuration of the long-term predicted ephemeris data 357. In the long-term predicted ephemeris data 357, the generation date and time 3571 of the long-term predicted ephemeris data and the predicted ephemeris 3573 (3573-1 to 3573-32) of the GPS satellites SV1 to SV32 are stored in association with each other.

  FIG. 10 is a diagram illustrating an example of a data configuration of the predicted ephemeris 3573. The predicted ephemeris 3573 (3573-1, 3573-2,..., 3573-32) includes Kepler satellite orbit parameter values such as an orbital length radius, an eccentricity, and an orbit inclination angle for each prediction target period. The value of the clock correction parameter consisting of the reference time of the satellite clock, the offset of the satellite clock, the drift of the satellite clock and the drift of the satellite clock frequency, and the value of the reliability parameter consisting of the predicted orbit reliability and the positioning inappropriate flag are stored. Yes.

  In the present embodiment, for each GPS satellite SV, the predicted orbit reliability and the positioning inadequate flag, which are reliability parameters, are the predicted orbit reliability totaling result data 3563 and the positioning inadequate flag totaling result data in the totaling result data 356 of FIG. Each is determined based on the total result stored in 3565.

  Specifically, 28 prediction target periods obtained by dividing one week, which is a generation target period, every 6 hours correspond to the first to 28th periods of the aggregation result data 356, respectively. For the predicted trajectory reliability, for each prediction target period, the predicted trajectory reliability having the highest aggregate value in the period corresponding to the prediction target period is determined, and determined as the predicted trajectory reliability in the prediction target period. To do. As for the positioning inappropriate flag, for each prediction target period, when the number of the flags counted in the period corresponding to the prediction target period exceeds a predetermined threshold, the positioning inappropriate flag in the prediction target period is set. Set to “ON”.

2-3. Process Flow FIG. 11 is a flowchart showing a flow of a long-term predicted ephemeris providing process executed in the server system 3 when the long-term predicted ephemeris providing program 341 stored in the ROM 340 is read and executed by the CPU 310. is there.

  First, the CPU 310 determines whether or not the satellite prediction calendar 351 has been received from the external system 2 (step A1). If it is determined that the satellite prediction calendar 351 has not been received (step A1; No), the process proceeds to step A5. . If it is determined that it has been received (step A1; Yes), the satellite prediction calendar 351 is updated and stored in the hard disk 350 (step A3).

  Next, the CPU 310 determines whether or not it is the generation time of the long-term predicted ephemeris (step A5). In the present embodiment, the long-term predicted ephemeris is generated once every 4 hours. If it is determined that the generation time is not yet reached (step A5; No), the CPU 310 proceeds to step A9.

  When it is determined that it is the generation time of the long-term predicted ephemeris (step A5; Yes), the CPU 310 reads out and executes the long-term predicted ephemeris generation program 3411 stored in the ROM 340, thereby executing the long-term predicted ephemeris generation process. (Step A7).

12 and 13 are flowcharts showing the flow of the long-term predicted ephemeris generation process.
First, the CPU 310 determines each prediction target period based on the current generation time and the current date (generation date / time) of the long-term predicted ephemeris (step B1). That is, the period from the current generation date and time to one week later is set as the generation target period, and each period obtained by dividing the generation target period every 6 hours is determined as the prediction target period.

  Next, the CPU 310 executes a process of loop A for each GPS satellite SV (steps B3 to B21). In the process of loop A, the CPU 310 executes the process of loop B for each prediction target period determined in step B1 (steps B5 to B17).

  In the process of Loop B, the CPU 310 starts from the satellite prediction calendar 351 stored in the hard disk 350 and each time of the prediction target period of the GPS satellite SV (every 15 minutes stored in the satellite prediction calendar 351). Then, the predicted position in the prediction target period is read out (step B7).

  Then, the CPU 310 calculates the predicted orbit of the GPS satellite SV in the prediction target period according to the elliptical orbit model of Kepler using the predicted position read in Step B7, and obtains the value of the Kepler satellite orbit parameter (Step B9). ). Since a specific method for calculating the predicted trajectory is known, detailed description thereof is omitted.

  Thereafter, the CPU 310 reads out the clock prediction error at each time in the prediction target period of the GPS satellite SV from the satellite prediction calendar 351 (step B11). Then, CPU 310 obtains the value of the clock correction parameter for the prediction target period of the GPS satellite using the read clock prediction error (step B13). Then, the CPU 310 shifts the process to the next prediction target period.

The clock prediction error “Δt” at time “t” includes the reference time “t _c ” of the satellite clock, which is the clock correction parameter, the offset “a ₀ ” of the satellite clock, the drift “a ₁ ” of the satellite clock, and the satellite clock frequency. The drift “a ₂ ” can be used to approximate the following equation (1).
Δt = a ₀ + a ₁ (t−t _c ) + a ₂ (t−t _c ) ² (1)

  Expression (1) is a clock error model expression for approximating the change with time of the clock prediction error. The clock correction parameter value can be calculated by performing approximate calculation using, for example, the least squares method with the clock prediction error “Δt” at each time included in the satellite prediction calendar 351 as sampling data.

  Thereafter, the CPU 310 determines the predicted orbit reliability and the positioning inappropriateness flag for the prediction target period of the GPS satellite SV based on the latest totaled result data 356 stored in the totaled result database 355, thereby improving the reliability. The parameter value is obtained (step B15). Then, the CPU 310 shifts the process to the next prediction target period.

  After performing the processing of Steps B7 to B15 for all the prediction target periods, the CPU 310 ends the processing of Loop B (Step B17). After that, the CPU 310 summarizes the values of the satellite orbit parameters obtained in step B9, the clock correction parameter values obtained in step B13, and the reliability parameter values obtained in step B15 for all the prediction target periods. A predicted ephemeris 3573 of the GPS satellite SV is generated (step B19). Then, the CPU 310 shifts the processing to the next GPS satellite SV.

  After performing the processing of Steps B5 to B19 for all the GPS satellites SV, the CPU 310 ends the processing of Loop A (Step B21). Thereafter, the CPU 310 collects the predicted ephemeris 3573 generated in step B19 for all GPS satellites SV, generates long-term predicted ephemeris data 357 in association with the generation date and time 3571, and stores it in the hard disk 350 (step B23). Then, the CPU 310 ends the long-term predicted ephemeris generation process.

  Returning to the long-term predicted ephemeris providing process of FIG. 11, after performing the long-term predicted ephemeris generation process, the CPU 310 determines whether or not a request signal for the long-term predicted ephemeris data 357 has been received from the mobile phone 4 (step A9). ). And when it determines with having not received (step A9; No), a process is transfered to step A13.

  If it is determined that the request signal has been received (step A9; Yes), the CPU 310 transmits the long-term predicted ephemeris data 357 stored in the hard disk 350 to the requesting mobile phone 4 (step A11).

  Thereafter, the CPU 310 determines whether or not the tabulation data 354 has been received from the mobile phone 4 (step A13), and if it is determined that it has not been received (step A13; No), the process returns to step A1. When it is determined that the data has been received (step A13; Yes), the CPU 310 updates the total value of the total result data 356 in accordance with the received total data 354 (step A15). Then, the CPU 310 returns to step A1.

3. 3. Mobile phone 3-1. Functional Configuration FIG. 14 is a block diagram showing a functional configuration of the mobile phone 4. The mobile phone 4 includes a GPS antenna 405, a GPS receiving unit 410, a host CPU 420, an operation unit 430, a display unit 440, a mobile phone antenna 450, a mobile phone wireless communication circuit unit 460, and a ROM 470. A flash ROM 480 and a RAM 490 are provided.

  The GPS antenna 405 is an antenna that receives an RF (Radio Frequency) signal including a GPS satellite signal transmitted from the GPS satellite SV, and outputs the received signal to the GPS receiving unit 410. The GPS satellite signal is a 1.57542 [GHz] communication signal modulated by a direct spread spectrum system with a PRN (Pseudo Random Noise) code which is a kind of spreading code different for each satellite. The PRN code is a pseudo-random noise code having a repetition period of 1 ms with a code length of 1023 chips as one PN frame.

  The GPS receiving unit 410 is a positioning circuit that performs positioning based on a signal output from the GPS antenna 405, and is a functional block corresponding to a so-called GPS receiver. The GPS receiving unit 410 includes an RF (Radio Frequency) receiving circuit unit 411 and a baseband processing circuit unit 413. The RF receiving circuit unit 411 and the baseband processing circuit unit 413 can be manufactured as separate LSIs (Large Scale Integration) or as a single chip.

  The RF receiving circuit unit 411 is an RF signal processing circuit block, and generates an oscillation signal for RF signal multiplication by dividing or multiplying a predetermined local oscillation signal. Then, by multiplying the generated oscillation signal by the RF signal output from the GPS antenna 405, the RF signal is down-converted to an intermediate frequency signal (hereinafter referred to as an “IF (Intermediate Frequency) signal”). Then, after amplifying the IF signal, it is converted into a digital signal by an A / D (Analog Digital) converter and output to the baseband processing circuit unit 413.

  The baseband processing circuit unit 413 is a circuit unit that performs correlation processing or the like on the IF signal output from the RF receiving circuit unit 411 to capture and extract a GPS satellite signal. The baseband processing circuit unit 413 includes a CPU 415 as a processor, and a ROM 417 and a RAM 419 as memories. The CPU 415 captures and extracts a GPS satellite signal using the long-term predicted ephemeris data 357 acquired from the server system 3 by the host CPU 420.

  The host CPU 420 is a processor that comprehensively controls each unit of the mobile phone 4 according to various programs such as a positioning calculation program and a system program stored in the ROM 470. The host CPU 420 performs a positioning calculation based on the GPS satellite signal captured and extracted by the baseband processing circuit unit 413. And the navigation screen which plotted the positioning position calculated | required by positioning calculation is displayed on the display part 440. FIG.

  The operation unit 430 is an input device configured by a touch panel, a button switch, or the like, for example, and outputs a pressed icon or button signal to the host CPU 420. By operating the operation unit 430, various instructions such as a call request, a mail transmission / reception request, and a GPS activation request are input.

  The display unit 440 is configured by an LCD (Liquid Crystal Display) or the like, and is a display device that performs various displays based on display signals input from the host CPU 420. The display unit 440 displays a navigation screen, time information, and the like.

  The cellular phone antenna 450 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 4.

  The mobile phone wireless communication circuit unit 460 is a mobile phone communication circuit unit that includes an RF conversion circuit, a baseband processing circuit, and the like, and performs modulation and demodulation of the mobile phone radio signal, thereby enabling communication and mailing. Realize transmission / reception and so on.

  The ROM 470 is a read-only nonvolatile storage device, and a system program for the host CPU 420 to control the mobile phone 4, a positioning calculation program for realizing a positioning calculation, and a navigation program for realizing a navigation function And various programs and data are stored.

  The flash ROM 480 is a readable / writable nonvolatile storage device, and stores various programs, data, and the like for the host CPU 420 to control the mobile phone 4, similarly to the ROM 470. The data stored in the flash ROM 480 is not lost even when the power of the mobile phone 4 is turned off.

  The RAM 490 is a readable / writable volatile storage device, and has a work area for temporarily storing a system program executed by the host CPU 420, a positioning calculation program, various processing programs, data being processed in various processing, processing results, and the like. Forming.

3-2. Data Configuration FIG. 15 is a diagram illustrating an example of data stored in the ROM 470. The ROM 470 stores a main program 471 that is read by the host CPU 420 and executed as main processing (see FIG. 21), and predicted orbit reliability correction data 473. The main program 471 includes a positioning program 4711 executed as a positioning process (see FIGS. 22 and 23), a positioning inappropriate satellite determination program 4713 executed as a positioning inappropriate satellite determination process (see FIG. 24), and an evaluation. An evaluation value calculation program 4715 executed as a value calculation process (see FIG. 25) is included as a subroutine.

  The main process is a process in which the host CPU 420 performs a call or mail transmission / reception, which is the original function of the mobile phone 4, and speeds up the initial positioning after the power of the mobile phone 4 is turned on. This is a process for performing a process (positioning process) for measuring the position of the mobile phone 4.

  In the positioning process, the host CPU 420 captures a GPS satellite from the GPS satellite SV using the long-term predicted ephemeris data 357 received from the server system 3, and from the captured GPS satellite (hereinafter referred to as "capture satellite"). This is a process of measuring the position of the mobile phone 4 based on the GPS satellite signal and outputting it to the display unit 440.

  The positioning unsuitable satellite determination process means that the host CPU 420 performs positioning calculation for each of a plurality of satellite combinations obtained by combining the number of acquisition satellites necessary for the positioning calculation (four in three-dimensional positioning). This is a process of determining a satellite unsuitable for positioning as a positioning unsuitable satellite from the inside.

  Further, the evaluation value calculation processing is obtained from the satellite position and clock error obtained from the ephemeris data 481 received from the captured satellite and the long-term predicted ephemeris data 357 received from the server system 3 for each captured satellite. This is a process for evaluating the captured satellite by calculating the evaluation value of the captured satellite using the satellite position and the clock error. These processes will be described later in detail using a flowchart.

  FIG. 18 is a diagram illustrating an example of the data configuration of the predicted trajectory reliability correction data 473. As illustrated in FIG. The predicted trajectory reliability correction data 473 is data used to correct the predicted trajectory reliability, and includes an evaluation value range 4731 indicating a range including the evaluation value calculated by the evaluation value calculation process, and the calculated evaluation. When a value is included in the evaluation value range 4731, an addition value 4733, which is a value added to the predicted trajectory reliability, is stored in association with each other.

  In the predicted trajectory reliability correction data 473, an evaluation value range 4731 and an added value 4733 are determined so that a higher value is added to the predicted trajectory reliability as the evaluation value is higher. For example, when the calculated evaluation value is included in the range of “20 to 30”, “2” is added to the predicted trajectory reliability. The higher the evaluation value, the larger the value is added to the predicted trajectory reliability, and the lower the reliability of the predicted trajectory.

  FIG. 16 is a diagram illustrating an example of data stored in the flash ROM 480. The flash ROM 480 stores tabulation data 354, long-term predicted ephemeris data 357 received from the server system 3, ephemeris data 481 received from the GPS satellite SV, and the latest positioning position 483 which is the latest positioning position. . The data structures of the data for aggregation 354 and the long-term predicted ephemeris data 357 are as described with reference to FIGS.

  The ephemeris data 481 is own satellite orbit information transmitted from each GPS satellite SV, and is obtained by decoding the GPS satellite signal captured by the baseband processing circuit unit 413. The ephemeris data 481 stores, for example, satellite orbit parameter values, clock correction parameter values, and reliability parameter values for 6 hours.

  FIG. 17 is a diagram illustrating an example of data stored in the RAM 490. The RAM 490 stores a captured satellite 491, a determination target satellite 492, a positioning inadequate satellite 493, satellite combination data 494, evaluation value data 495, and an output position 496.

  The captured satellite 491 is identification information indicating the GPS satellite SV captured by the baseband processing circuit unit 413. The determination target satellite 492 is identification information indicating the GPS satellite SV to be determined in the positioning inappropriate satellite determination process. Further, the positioning inadequate satellite 493 is identification information indicating the GPS satellite SV determined as a satellite inadequate for positioning in the positioning inadequate satellite determination process.

  FIG. 19 is a diagram illustrating an example of a data configuration of the satellite combination data 494. The satellite combination data 494 is data on the combination of satellites used in the positioning inappropriate satellite determination process, and the satellite combination 4941, the excluded satellite 4943, the positioning position 4945, and the distance 4947 from the average position are associated with each other. It is remembered.

  The excluded satellite 4943 is identification information indicating a GPS satellite SV excluded from the satellite combination 4941 among the determination target satellites 492. The positioning position 4945 is a position obtained by performing positioning calculation on the satellite combination 4941. The distance 4947 from the average position is a position obtained by averaging the positioning positions 4945 of all the satellite combinations 4941 (hereinafter referred to as “average position”), and the positioning position obtained for the satellite combination 4941. 4945.

  FIG. 20 is a diagram illustrating an example of a data configuration of the evaluation value data 495. The evaluation value data 495 is data used in the evaluation value calculation process. The acquisition satellite 4951, the first satellite position 4952, the second satellite position 4953, the first clock error 4954, and the second A clock error 4955, a distance between satellite positions 4956, a clock error difference 4957, and an evaluation value 4958 are stored in association with each other.

  The first satellite position 4952 is the satellite position of the captured satellite at the current date and time calculated using the satellite orbit parameter value of the captured satellite included in the ephemeris data 481. On the other hand, the second satellite position 4953 is the satellite position of the captured satellite at the current date and time calculated using the values of the satellite orbit parameters of the captured satellite included in the long-term predicted ephemeris data 357.

  The first clock error 4954 is a clock error of the captured satellite at the current date and time calculated using the value of the clock correction parameter of the captured satellite included in the ephemeris data 481. On the other hand, the second clock error 4955 is the clock error of the captured satellite at the current date and time calculated using the value of the clock correction parameter of the captured satellite included in the long-term predicted ephemeris data 357.

  The inter-satellite position distance 4956 is a distance between the first satellite position 4952 and the second satellite position 4953. The clock error difference 4957 is a difference between the first clock error 4954 and the second clock error 4955.

  The evaluation value 4958 is an evaluation value of the captured satellite calculated using the inter-satellite position distance 4956 and the clock error difference 4957. The evaluation value 4958 can be formulated by a function such that the value becomes smaller as the reliability of the predicted orbit of the captured satellite 4951 is higher. That is, the smaller the evaluation value, the better.

For example, when the distance between the satellite positions is “dP” and the difference between the clock errors is “dT”, the evaluation value “E” can be calculated according to the following equation (2).
E = α · dP + β · dT (2)
Here, “α” and “β” in Equation (2) are positive constants. However, since the unit between the distance between the satellite positions and the difference between the clock errors is different, it is not always possible to treat each value as it is. For this reason, it is more preferable if the values of “α” and “β” can be adjusted to appropriate values.

  The higher the accuracy of the values of the satellite orbit parameters included in the long-term predicted ephemeris data 357, the higher the first satellite position 4952 obtained from the ephemeris data 481 and the second satellite position 4953 obtained from the long-term predicted ephemeris data 357. As the distance approaches, the inter-satellite position distance 4956 decreases. Further, the higher the accuracy of the value of the clock correction parameter included in the long-term predicted ephemeris data 357, the first clock error 4954 obtained from the ephemeris data 481 and the second clock error 4955 obtained from the long-term predicted ephemeris data 357. The clock error difference 4957 becomes smaller. Therefore, it can be seen from equation (2) that the evaluation value decreases as the accuracy of the parameter value included in the long-term predicted ephemeris data 357 increases (the reliability of the predicted trajectory increases).

  The output position 496 is a position (hereinafter referred to as “output position”) determined as a position to be finally output to the display unit 440 in the positioning process.

3-3. Processing Flow FIG. 21 is a flowchart showing a main processing flow executed in the mobile phone 4 when the host CPU 420 reads and executes the main program 471 stored in the ROM 470.

  The main process is a process for starting execution when the host CPU 420 detects that a power-on operation has been performed by the user via the operation unit 430. Although not specifically described, during execution of the following main processing, the RF signal is received by the GPS antenna 405 and the RF signal is down-converted to the IF signal by the RF receiving circuit unit 411 so that the IF signal is baseband. It is assumed that the data is output to the processing circuit unit 413 as needed.

  First, the host CPU 420 determines an instruction operation performed via the operation unit 430 (step C1), and determines that the instruction operation is a call instruction operation (step C1; call instruction operation), performs call processing. (Step C3). Specifically, the mobile phone radio communication circuit unit 460 performs base station communication with the radio base station, thereby realizing a call between the mobile phone 4 and another device.

  If it is determined in step C1 that the instruction operation is a mail transmission / reception instruction operation (step C1; mail transmission / reception instruction operation), the host CPU 420 performs mail transmission / reception processing (step C5). Specifically, base station communication is performed by the mobile phone wireless communication circuit unit 460 to realize transmission / reception of mail between the mobile phone 4 and another device.

  If it is determined in step C1 that the instruction operation is an initial positioning acceleration instruction operation (step C1; initial positioning acceleration instruction operation), the host CPU 420 performs an initial positioning acceleration process (step C7). Specifically, a request signal for long-term predicted ephemeris data 357 is transmitted to the server system 3. Then, the long-term predicted ephemeris data 357 is received from the server system 3 and is updated and stored in the flash ROM 480.

  When it is determined in step C1 that the instruction operation is a positioning instruction operation (step C1; positioning instruction operation), the host CPU 420 reads out and executes the positioning program 4711 stored in the ROM 470, thereby performing a positioning process. (Step C9).

22 and 23 are flowcharts showing the flow of the positioning process.
First, the host CPU 420 determines a period including the current date and time (hereinafter referred to as “the period”) from the prediction target periods stored in the long-term predicted ephemeris data 357 of the flash ROM 480 (step D1). .

  Then, the host CPU 420 performs capture target satellite determination processing (step D3). More specifically, the GPS satellite SV located in the sky at the latest positioning position 483 stored in the flash ROM 480 is determined using the long-term predicted ephemeris data 357 at the current time measured by a clock unit (not shown). The satellite to be captured.

  Next, the host CPU 420 executes the process of loop C for each capture target satellite (steps D5 to D19). In the process of loop C, the host CPU 420 selects the value of the satellite orbit parameter of the capture target satellite in the period included in the long-term predicted ephemeris data 357 of the flash ROM 480 (step D7).

  Then, the host CPU 420 configures a predicted orbit based on the Kepler elliptical orbit model using the value of the satellite orbit parameter selected in Step D7 (Step D9). Then, the satellite position of the capture target satellite at the current date and time is calculated from the configured predicted orbit (step D11).

  Thereafter, the host CPU 420 uses the satellite position calculated in step D11 and the latest positioning position 483 stored in the flash ROM 480, and receives the GPS satellite signal of the capture target satellite at the latest positioning position 483. The frequency is calculated (step D13).

  Next, the host CPU 420 performs a frequency search range setting process for setting a frequency search range when receiving a GPS satellite signal from the capture target satellite using the Doppler frequency calculated in Step D13 (Step D15). . That is, the frequency search range is changed according to the magnitude of the Doppler frequency.

  Then, the host CPU 420 performs satellite signal acquisition processing (step D17). Specifically, by causing the CPU 415 of the baseband processing circuit unit 413 to perform a frequency search within the frequency search range set in step D15, the acquisition of the GPS satellite signal from the acquisition target satellite was attempted and the acquisition was successful. The acquisition target satellite is stored in the RAM 490 as the acquisition satellite 491. Then, the host CPU 420 shifts the process to the next capture target satellite.

  After performing the processing of steps D7 to D17 for all the capture target satellites, the host CPU 420 ends the processing of loop C (step D19). Thereafter, the host CPU 420 determines whether or not there are surplus satellites in the captured satellite 491 (step D21). In three-dimensional positioning (positioning including altitude), at least four captured satellites are required. Therefore, when the number of captured satellites 491 is five or more, it is determined that there are surplus satellites.

  And when it determines with there being no surplus satellite (step D21; No), the host CPU420 transfers a process to step D27. If it is determined that there are surplus satellites (step D21; Yes), the host CPU 420 reads out and executes the positioning inappropriate satellite determination program 4713 stored in the ROM 470, thereby performing positioning inappropriate satellite determination processing ( Step D23).

FIG. 24 is a flowchart showing the flow of positioning inappropriate satellite determination processing.
First, the host CPU 420 stores all captured satellites 491 as determination target satellites 492 in the RAM 490 (step E1). Then, a satellite combination 4941 in which one satellite is excluded from the determination target satellites 492 is calculated and stored in the satellite combination data 494 of the RAM 490 together with the excluded satellite 4943 (step E3).

  Next, the host CPU 420 executes the process of loop D for each of the satellite combinations calculated in step E3 (steps E5 to E9). In the process of loop D, the host CPU 420 performs a positioning calculation on the satellite combination to obtain a positioning position 4945 and stores it in the satellite combination data 494 (step E7).

  More specifically, the host CPU 420 reads the value of the clock correction parameter of each satellite included in the satellite combination of the period included in the long-term predicted ephemeris data 357, and uses the value of the correction parameter to express the formula (1 ) To calculate the clock error at the current date and time. Then, using the GPS satellite signal transmission time from each satellite and the reception time of the GPS satellite signal in the mobile phone 4 and the calculated clock error, the pseudo distance between each satellite and the mobile phone 4 is calculated, Using the calculated pseudo distance, for example, positioning calculation using a least square method or a Kalman filter is performed.

  After performing the positioning calculation in step E7, the host CPU 420 shifts the process to the next satellite combination. After performing the process of step E7 for all the satellite combinations, the host CPU 420 ends the process of loop D (step E9). Thereafter, the host CPU 420 calculates the average position by averaging the positioning positions 4945 obtained for the respective satellite combinations (step E11).

  Next, the host CPU 420 calculates the distance between the positioning position 4945 obtained at step E7 and the average position calculated at step E11 (distance 4947 from the average position) for each satellite combination, and stores it in the satellite combination data 494. (Step E13). Then, the host CPU 420 performs threshold determination for the calculated distance 4947 from the average position (step E15).

  Thereafter, the host CPU 420 determines whether or not there is a satellite combination in which the distance 4947 from the average position exceeds the threshold value (step E17). If it is determined that there is no satellite combination (step E17; No), the positioning inappropriate satellite determination process is performed. Exit. If it is determined that there is a satellite (step E17; Yes), the host CPU 420 determines that the excluded satellite 4943 in the satellite combination is a positioning inappropriate satellite 493 and stores it in the RAM 490 (step E19).

  Then, the host CPU 420 deletes the positioning inappropriate satellite 493 from the determination target satellite 492 stored in the RAM 490 (step E21). Then, the host CPU 420 determines whether or not the number of the determination target satellites 492 is less than 5 (step E23), and when it is determined that the number is not less than 5 (step E23; No), the step E3 Return to. If it is determined that the number is less than 5 (step E23; Yes), the positioning inappropriate satellite determination process is terminated.

  The satellite combinations calculated in step E3 are all satellite combinations including positioning-inappropriate satellites, except for satellite combinations from which positioning-inappropriate satellites are excluded (hereinafter referred to as “positioning-inappropriate satellite exclusion combinations”). Therefore, in step E7, the average position calculated by averaging the positioning positions obtained for these satellite combinations is a position with poor accuracy because it is affected by positioning inappropriate satellites. On the other hand, since the positioning position obtained for the positioning inappropriate satellite exclusion combination is not affected by the positioning inappropriate satellite, it is a highly accurate position. Therefore, the positioning position obtained for the positioning inappropriate satellite exclusion combination has a distance from the average position exceeding the threshold (step E17; Yes), and the excluded satellite at this time is determined as a positioning inappropriate satellite. (Step E19).

  Returning to the positioning process of FIG. 23, after performing the positioning inappropriate satellite determination process, the host CPU 420 sets the positioning inappropriate flag for the positioning inappropriate satellite 493 in the long-term predicted ephemeris data 357 stored in the flash ROM 480. “ON” is set (step D25). Then, the host CPU 420 reads out and executes the evaluation value calculation program 4715 stored in the ROM 470, thereby performing evaluation value calculation processing (step D27).

FIG. 25 is a flowchart showing the flow of the evaluation value calculation process.
First, the host CPU 420 executes the process of loop E for each of the captured satellites 491 (steps F1 to F17). In the process of loop E, the host CPU 420 calculates the satellite position of the captured satellite at the current date and time using the value of the satellite orbit parameter of the captured satellite included in the ephemeris data 481 of the flash ROM 480, and the first satellite position 4952. Is stored in the evaluation value data 495 (step F3).

  Similarly, the host CPU 420 calculates the satellite position of the captured satellite at the current date and time using the value of the satellite orbit parameter of the captured satellite included in the long-term predicted ephemeris data 357 of the flash ROM 480 as a second satellite position 4953. The evaluation value data 495 is stored (step F5).

  Then, the host CPU 420 calculates the distance between the first satellite position 4952 calculated in step F3 and the second satellite position 4953 calculated in step F5, and stores the distance between satellite positions 4956 in the evaluation value data 495. Store (step F7).

  Thereafter, the host CPU 420 calculates the clock error of the captured satellite at the current date and time according to Equation (1) using the value of the clock correction parameter of the captured satellite included in the ephemeris data 481 and evaluates it as the first clock error 4954. The value data 495 is stored (step F9).

  Similarly, the host CPU 420 calculates the clock error of the captured satellite at the current date and time according to the equation (1) using the value of the clock correction parameter of the captured satellite included in the long-term predicted ephemeris data 357, and the second clock error The evaluation value data 495 is stored as 4955 (step F11).

  Then, the host CPU 420 calculates the difference between the first clock error 4954 calculated in step F9 and the second clock error 4955 calculated in step F11, and stores it in the evaluation value data 495 as a clock error difference 4957. (Step F13).

  Thereafter, the host CPU 420 calculates an evaluation value 4958 according to Equation (2) using the distance between satellite positions 4956 calculated in Step F7 and the difference in clock error 4957 calculated in Step F13, and the evaluation value data 495 is obtained. Store (step F15). Then, the host CPU 420 shifts the process to the next acquisition satellite.

  After performing the processing of Steps F3 to F15 for all captured satellites, the host CPU 420 ends the processing of Loop E (Step F17). Then, after completing the process of Loop E, the host CPU 420 ends the evaluation value calculation process.

  Returning to the positioning process of FIG. 23, after performing the evaluation value calculation process, the host CPU 420 predicts the predicted trajectory of each captured satellite in the current period stored in the long-term predicted ephemeris data 357 of the flash ROM 480 according to the calculated evaluation value. The reliability is corrected (step D29). Specifically, with reference to predicted orbit reliability correction data 473 stored in ROM 470, an evaluation value range 4731 including the calculated evaluation value is determined for each captured satellite. Then, the addition value 4733 corresponding to the determined evaluation value range 4731 is added to the predicted orbit reliability of the captured satellite.

  Thereafter, the host CPU 420 collects the predicted orbit reliability of each captured satellite and the positioning inadequate flag to generate reliability data 3545 (step D31). Then, tabulation data 354 in which the terminal ID 3541, the period number 3543, and the generated reliability data 3545 are associated with each other is generated and stored in the flash ROM 480 (step D33).

  Thereafter, the host CPU 420 transmits the generated aggregation data 354 to the server system 3 (step D35). Then, the host CPU 420 uses the combination of satellites used for positioning based on the reliability parameter values (predicted orbit reliability and positioning inadequate flag) of each captured satellite in the period included in the long-term predicted ephemeris data 357 of the flash ROM 480 ( Hereinafter, it is referred to as “positioning satellite combination”) (step D37).

  Specifically, for example, a captured satellite having a predicted orbit reliability smaller than “5” (a satellite having a high predicted orbit reliability) is selected from the captured satellites whose positioning inadequate flag is set to “OFF”. To do. Then, the satellite combination of the selected acquisition satellites is determined as the positioning satellite combination.

  Next, the host CPU 420 executes positioning calculation for the positioning satellite combination determined in step D37, stores the positioning position in the RAM 490 as the output position 496, and stores it in the flash ROM 480 as the latest positioning position 483 (step D39). . Then, the host CPU 420 outputs the output position 496 to the display unit 440 to display the navigation screen (step D41), and then ends the positioning process.

  Returning to the main process of FIG. 21, after performing any one of steps C3 to C9, the host CPU 420 determines whether or not the user has performed a power-off instruction operation via the operation unit 430 (step C11). ), When it is determined that it has not been made (step C11; No), the process returns to step C1. If it is determined that the power-off instruction operation has been performed (step C11; Yes), the main process is terminated.

4). In the positioning system 1, the mobile phone 4 uses the long-term predicted ephemeris data received from the server system 3 to perform positioning calculation based on a plurality of satellite combinations obtained by combining more than the number of GPS satellites SV necessary for positioning. Do. The reliability of the predicted orbit of each GPS satellite SV included in the long-term predicted ephemeris data is based on the difference between the GPS satellites SV included in the plurality of satellite combinations and the difference in the positioning calculation results performed on the plurality of satellite combinations. Determine.

  If there is a positioning calculation result that differs greatly from other positioning calculation results among the positioning calculation results performed for multiple satellite combinations, the positioning combination is used in the satellite combination used when calculating the positioning calculation result. May contain improper satellites. Therefore, the reliability of the predicted orbit of each GPS satellite SV is determined by determining the unsuitable positioning satellite based on the difference between the GPS satellites SV included in the plurality of satellite combinations and determining the reliability of the predicted orbit of the unsuitable positioning satellite low. Gender can be determined appropriately.

  Further, the mobile phone 4 uses the satellite position and clock error obtained from the ephemeris data received from the GPS satellite SV and the satellite position and clock error obtained from the long-term predicted ephemeris data received from the server system 3, respectively. An evaluation value is calculated for the GPS satellite SV, and the reliability of the predicted orbit is determined using the evaluation value.

  The distance between the satellite position obtained from the ephemeris data and the satellite position obtained from the long-term predicted ephemeris data (distance between satellite positions), and the difference between the clock error obtained from the ephemeris data and the clock error obtained from the long-term predicted ephemeris data ( The smaller the difference (clock error), the smaller the evaluation value and the higher the reliability of the predicted trajectory.

  As described above, the reliability of the predicted orbit of each GPS satellite SV is appropriately determined by the determination using the difference in the satellite position and the difference in the clock error obtained from the ephemeris data and the long-term predicted ephemeris data for each GPS satellite SV. be able to.

  Further, in the present embodiment, the plurality of mobile phones 4 transmit the determination result of the reliability of the predicted orbit determined for each GPS satellite SV to the server system 3. Then, the server system 3 tabulates the reliability determination results received from the plurality of mobile phones 4, and determines the reliability of the predicted orbit of each GPS satellite SV based on the tabulation results. Then, long-term predicted ephemeris data including the determined reliability is generated and transmitted to the mobile phone 4.

  Thereby, the server system 3 predicts each GPS satellite SV to be included in the long-term predicted ephemeris data to be generated based on the determination result of the reliability of the predicted orbit of each GPS satellite SV determined by the mobile phone 4. The reliability of the trajectory can be determined, and it becomes possible to provide the mobile phone 4 with statistically determined reasonable reliability.

5). Modified example 5-1. Positioning System In the above-described embodiment, the positioning system 1 including the server system 3 and the mobile phone 4 has been described as an example. However, the positioning system to which the present invention can be applied is not limited thereto. For example, instead of the mobile phone 4, the present invention can be applied to electronic devices such as a notebook personal computer equipped with a positioning device, a PDA (Personal Digital Assistant), and a car navigation device.

5-2. In the above-described embodiment, the GPS has been described as an example of the satellite positioning system. However, WAAS (Wide Area Augmentation System), QZSS (Quasi Zenith Satellite System), GLONASS (GLObal NAvigation Satellite System), GALILEO Other satellite positioning systems may be used.

5-3. Positioning Inappropriate Satellite Determination Processing FIG. 26 is a flowchart showing a flow of second positioning inadequate satellite determination processing, which is processing related to determination of a positioning inadequate satellite in the modification. The second positioning unsuitable satellite determination process does not compare the positioning calculation results performed for each satellite combination, but the positioning calculation results performed for all the satellites to be determined for determination and the positioning results for each satellite combination. Is a process for determining a positioning inappropriate satellite. Note that the same steps as those in the positioning inadequate satellite determination process in FIG. 24 are denoted by the same reference numerals and description thereof will be omitted, and description will be made focusing on portions different from the positioning inadequate satellite determination processing.

  The host CPU 420 stores the determination target satellite in the RAM 490 in step E1 (step E1), and then performs positioning calculation using all the determination target satellites, and stores the positioning position in the RAM 490 as the reference positioning position ( Step G2). Then, the host CPU 420 calculates a satellite combination from which one satellite is excluded from the determination target satellites, and stores it in the RAM 490 (step E3).

  Thereafter, the host CPU 420 executes processing of loop F for each satellite combination (steps G5 to G11). In the process of loop F, the host CPU 420 performs a positioning calculation on the satellite combination to obtain a positioning position, and stores it in the RAM 490 (step G7).

  Next, the host CPU 420 calculates a distance between the positioning position obtained in step G7 and the reference positioning position obtained in step G2 (hereinafter referred to as “distance from the reference positioning position”), and stores it in the RAM 490. (Step G9). Then, the host CPU 420 shifts the process to the next satellite combination.

  After performing the processing of steps G7 and G9 for all satellite combinations, the host CPU 420 ends the processing of loop F (step G11). Thereafter, the host CPU 420 determines a threshold for the distance from the reference positioning position calculated in step G9 for each satellite combination (step G13).

  Then, the host CPU 420 determines whether or not there is a satellite combination whose distance from the reference positioning position exceeds the threshold (step G15). If it is determined that there is no satellite combination (step G15; No), the second positioning inappropriateness is determined. The satellite determination process is terminated. If it is determined that there is any (step G15; Yes), the process proceeds to step E19.

5-4. Evaluation Value Calculation Processing FIG. 27 is a flowchart showing a flow of second evaluation value calculation processing that is processing related to calculation of evaluation values in the modification. The second evaluation value calculation process is a process of calculating the evaluation value using the line-of-sight distance instead of calculating the evaluation value using the satellite position and the clock error.

  First, the host CPU 420 executes processing of loop G for each captured satellite (steps H1 to H19). In the loop G, the host CPU 420 calculates the satellite position of the captured satellite at the current date and time using the value of the satellite orbit parameter of the captured satellite included in the ephemeris data 481 of the flash ROM 480, and stores it in the RAM 490 as the first satellite position. Store (step H3).

  Further, the host CPU 420 calculates the clock error of the captured satellite at the current date and time using the value of the clock correction parameter of the captured satellite included in the ephemeris data 481, and stores it in the RAM 490 as the first clock error (step H5). ).

  Then, the host CPU 420 calculates a distance obtained by adding a distance corresponding to the first clock error to the distance between the center of the earth and the first satellite position, and stores it in the RAM 490 as the first line-of-sight distance (step H7).

  Similarly, the host CPU 420 calculates the satellite position of the captured satellite at the current date and time using the value of the satellite orbit parameter of the captured satellite included in the long-term predicted ephemeris data 357 of the flash ROM 480, and uses the RAM 490 as the second satellite position. (Step H9).

  Further, the host CPU 420 calculates the clock error of the captured satellite at the current date and time using the value of the clock correction parameter of the captured satellite included in the long-term predicted ephemeris data 357, and stores it in the RAM 490 as the second clock error ( Step H11).

  Then, the host CPU 420 calculates a distance obtained by adding a distance corresponding to the second clock error to the distance between the center of the earth and the second satellite position, and stores it in the RAM 490 as the second line-of-sight distance (step H13).

  Thereafter, the host CPU 420 calculates a difference between the first line-of-sight distance calculated in step H7 and the second line-of-sight distance calculated in step H13 (hereinafter referred to as “line-of-sight distance difference”) (step H15). ). Then, the host CPU 420 calculates the evaluation value of the captured satellite using the calculated line-of-sight distance difference (step H17).

When the difference in the line-of-sight distance is “dr”, the evaluation value “E” can be calculated according to the following equation (3), for example.
E = λ · dr (3)
However, “λ” is a positive constant.

  The higher the accuracy of the value of the satellite orbit parameter included in the long-term predicted ephemeris data 357, the closer the first satellite position and the second satellite position are. Further, the higher the accuracy of the clock correction parameter value included in the long-term predicted ephemeris data 357, the closer the first clock error and the second clock error are. In this case, the first line-of-sight distance and the second line-of-sight distance are approximated, and the line-of-sight distance difference is small. Therefore, it can be seen from equation (3) that the evaluation value decreases as the accuracy of the parameter value included in the long-term predicted ephemeris data 357 (the reliability of the predicted trajectory) increases.

  Thereafter, the host CPU 420 shifts the processing to the next captured satellite. After performing the processing of steps H3 to H17 for all the captured satellites, the host CPU 420 ends the processing of loop G (step H19). Then, the host CPU 420 ends the second evaluation value calculation process.

5-5. Determination of positioning satellite combination In the above-described embodiment, among the captured satellites whose positioning inadequate flag is set to “OFF”, the captured satellite whose predicted orbit reliability is smaller than “5” (the reliability of the predicted orbit is However, the positioning satellite combination determining method can be set as appropriate.

  For example, a predetermined number (for example, “6”) of acquisition satellites are selected in the order of decreasing predicted orbit reliability (in descending order of reliability of predicted orbit) from among the acquired satellites whose positioning inappropriateness flag is set to “OFF”. Thus, a positioning satellite combination may be configured. In addition, if the number of satellites required for positioning calculation is less than the number of satellites required for positioning calculation with only the acquired satellites whose positioning inappropriate flag is set to “OFF”, the captured satellites whose positioning inappropriate flag is set to “ON” are used. Also good.

5-6. Generation of Long-Term Predicted Ephemeris In the above-described embodiment, the server system 3 has been described as generating long-term predicted ephemeris data and providing it to the mobile phone 4. However, the mobile phone 4 itself generates long-term predicted ephemeris data. It is good. That is, the mobile phone 4 periodically acquires a satellite prediction calendar from the external system 2 and executes long-term prediction ephemeris generation processing using the acquired satellite prediction calendar, thereby generating long-term prediction ephemeris data. The same applies to the case where the present invention is applied to an electronic device such as a notebook personal computer equipped with a positioning device, a PDA, or a car navigation device instead of the mobile phone 4.

  In the above-described embodiment, the server system 3 generates long-term predicted ephemeris data at a predetermined time interval (for example, once every four hours) and receives a request for long-term predicted ephemeris data from the mobile phone 4. In this case, the long-term predicted ephemeris data that has been generated is described as being transmitted. Instead of such a configuration, the server system 3 may generate long-term predicted ephemeris data and transmit it to the portable phone 4 when receiving a request for long-term predicted ephemeris data from the portable phone 4.

5-7. Generation target period In the above-described embodiment, it has been described that the long-term predicted ephemeris is generated with the period up to one week after the generation date and time of the long-term predicted ephemeris as a reference, but the generation target period is longer than one week. A period (for example, two weeks) may be used, or a period shorter than one week (for example, three days) may be used. The ephemeris as navigation data transmitted from the GPS satellite SV generally has an effective period of about 4 hours. However, the long-term predicted ephemeris only needs to have a longer effective period than ephemeris as the navigation data transmitted from the GPS satellite SV. One day or more is preferable.

5-8. Prediction target period In the above-described embodiment, the length of the prediction target period has been described as 6 hours. However, the present invention is not limited to this and may be 4 hours or 8 hours, and can be set as appropriate. Of course.

The figure which shows schematic structure of a positioning system. The block diagram which shows the function structure of a server system. The figure which shows an example of the data stored in ROM of a server system. The figure which shows an example of the data stored in the hard disk of a server system. The figure which shows an example of the data structure of a satellite prediction calendar. The figure which shows an example of a data structure of the database for totalization. The figure which shows an example of a data structure of a total result database. The graph which shows an example of the time change of prediction error. The figure which shows an example of a data structure of long-term prediction ephemeris data. The figure which shows an example of a data structure of prediction ephemeris. The flowchart which shows the flow of a long-term prediction ephemeris provision process. The flowchart which shows the flow of a long-term prediction ephemeris production | generation process. The flowchart which shows the flow of a long-term prediction ephemeris production | generation process. The block diagram which shows the function structure of a portable telephone. The figure which shows an example of the data stored in ROM of a mobile telephone. The figure which shows an example of the data stored in flash ROM of a portable telephone. The figure which shows an example of the data stored in RAM of a mobile telephone. The figure which shows an example of the data structure of the data for prediction trajectory reliability correction. The figure which shows an example of a data structure of satellite combination data. The figure which shows an example of a data structure of evaluation value data. The flowchart which shows the flow of a main process. The flowchart which shows the flow of a positioning process. The flowchart which shows the flow of a positioning process. The flowchart which shows the flow of a positioning unsuitable satellite determination process. The flowchart which shows the flow of an evaluation value calculation process. The flowchart which shows the flow of a 2nd positioning improper satellite determination process. The flowchart which shows the flow of a 2nd evaluation value calculation process.

Explanation of symbols

1 positioning system 2 external system 3 server system
4 mobile phone, 310 CPU, 320 operation unit, 330 communication unit,
340 ROM, 350 hard disk, 360 RAM, 370 bus,
405 GPS antenna, 410 GPS receiving unit, 411 RF receiving circuit unit,
413 Baseband processing circuit unit, 415 CPU, 417 ROM,
419 RAM, 420 host CPU, 430 operation unit, 440 display unit,
450 antenna for mobile phone, 460 wireless communication circuit for mobile phone,
470 ROM, 480 Flash ROM, 490 RAM, SV GPS satellite

Claims (8)

Using the long-term predicted orbit data for predicting satellite orbits for one day or more, performing the positioning calculation based on a plurality of satellite combinations combining a number of positioning satellites more than necessary for the positioning calculation;
Determining the reliability of the long-term predicted orbit data based on the result of the positioning calculation of the plurality of satellite combinations;
Reliability determination method for long-term predicted orbit data including   Based on the difference between the positioning satellites included in the plurality of satellite combinations and the difference in the result of the positioning calculation performed on the plurality of satellite combinations, the predicted orbits of the positioning satellites included in the long-term predicted orbit data The method for determining reliability of long-term predicted orbit data according to claim 1, comprising determining reliability. Receiving satellite orbit data of the positioning satellite from the positioning satellite;
Determining the reliability of the long-term predicted orbit data based on the difference between the satellite position determined from the satellite orbit data and the satellite position determined from the long-term predicted orbit data;
The method for determining reliability of long-term predicted orbit data according to claim 1 or 2. Receiving satellite orbit data of the positioning satellite from the positioning satellite;
Determining the reliability of the long-term predicted orbit data based on the difference between the satellite position obtained from the satellite orbit data and the satellite position obtained from the long-term predicted orbit data obtained by predicting the satellite orbit for one day or more;
Reliability determination method for long-term predicted orbit data including The long-term predicted orbit data includes clock prediction error data obtained by predicting an error of the satellite clock of the positioning satellite,
The positioning satellite transmits the satellite orbit data including the clock error data of the satellite clock of the positioning satellite,
The reliability is determined by adding a position error corresponding to a clock error obtained from the clock error data to a satellite position obtained from the satellite orbit data, and a satellite position obtained from the long-term predicted orbit data. Determining the reliability of the long-term predicted trajectory data based on the difference from the position taking into account the position error corresponding to the clock error obtained from the clock prediction error data.
The method for determining reliability of long-term predicted orbit data according to claim 3 or 4.   A positioning method for performing a positioning calculation using a combination of positioning satellites determined to be highly reliable by the reliability determination method for long-term predicted orbit data according to any one of claims 1 to 5. A positioning calculation unit for performing the positioning calculation based on a combination of a plurality of satellites combining a number of positioning satellites more than necessary for the positioning calculation, using long-term predicted orbit data in which satellite orbits for one day or more are predicted;
A determination unit that determines the reliability of the long-term predicted orbit data based on a result of the positioning calculation of the plurality of satellite combinations;
Positioning device equipped with. A positioning system comprising a plurality of positioning devices and a server system that provides the positioning devices with long-term predicted orbit data in which satellite orbits for one or more days of positioning satellites are predicted,
The plurality of positioning devices are:
Using the long-term predicted orbit data received from the server system, a positioning calculation unit that performs the positioning calculation based on a plurality of satellite combinations that combine a number of positioning satellites more than necessary for the positioning calculation;
A determination unit that determines the reliability of the long-term predicted orbit data based on a result of the positioning calculation of the plurality of satellite combinations;
A transmission unit for transmitting the reliability determination result to the server system;
With
The server system is
A tabulation unit that tabulates the reliability determination results received from the plurality of positioning devices;
A determination unit that determines the reliability of the long-term predicted orbit data based on the aggregation result of the aggregation unit;
A providing unit that provides the positioning device with the reliability determined by the determining unit;
With
Positioning system.

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