JP2008281552A - Method and program for calculating and determining first located output position, storage medium, positioning device, and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To appropriately determine according to receiving environment which one out of increase in positioning accuracy and reduction in TTFF should be given priority to, on the occasion of outputting first positioning results. <P>SOLUTION: In the first positioning, a positioning process that calculates the present position based on acquired GPS satellite signals (step A3) is performed a plurality of times repeatedly. A number of times that the difference (position difference) ΔP between the calculated present located position and the preceding located position is successively equal to or less than a predetermined value is counted using a position counter, and a number of times that the difference (time difference) ΔT between the present time error and the preceding time error is successively equal to or less than a predetermined value is counted using a time counter each time the positioning process is performed (step A5). A position threshold value and a time threshold value are determined by changing a reference threshold value by an amount corresponding to an APR average value (step A7). When the position count value has reached the position threshold value (step A9: YES) and the time count value has reached the time threshold value (step A11: YES), the present located position is determined to be the first located position and output (step A13). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an initial positioning output position calculation determination method, a program, a storage medium, a positioning device, and an electronic apparatus.

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

By the way, the captured GPS satellite signal may include a GPS satellite signal affected by multipath or the like. That is, multipath means that an indirect wave reflected or diffracted from a building or terrain is superimposed on a direct wave from a GPS satellite, and the same radio wave is received from a plurality of paths. Such a reception environment is called a multipath environment. If a GPS satellite signal affected by the multipath is used, there is a possibility that the current position cannot be calculated (positioned) accurately. In other words, it is necessary to perform positioning calculation by removing GPS satellite signals that are affected by multipath or the like from the captured GPS satellite signals. Therefore, as one of methods for discriminating a GPS satellite signal affected by multipath or the like, a method using an inductive residual APR is known (see, for example, Patent Document 1).
JP 2003-240836 A

  In addition, the GPS receiver repeatedly performs a positioning calculation every predetermined time (for example, every second), and outputs the calculated current position as a positioning result. From the start of positioning to the output of the first positioning result, Usually it takes several seconds. Between the time TTFF (Time to First Fix) required for the output of the first positioning position and the positioning accuracy, if the TTFF is shortened, the positioning accuracy is lowered. Conversely, if priority is given to the improvement of the positioning accuracy, TTFF There is a relationship that tends to be long, and it is different depending on the reception environment which of the positioning accuracy and TTFF reduction should be given priority. For example, in a reception environment with low overall positioning accuracy such as a multipath environment, positioning accuracy is prioritized over shortening TTFF, and even if TTFF becomes long, the Z count is decoded and the positioning accuracy is improved. Should be output. On the other hand, since the positioning accuracy is high in the open sky environment, it is possible to give priority to the shortening of TTFF and output the positioning result without waiting for the decoding of the Z count.

  The present invention has been made in view of the above circumstances, and appropriately determines whether to give priority to the improvement of positioning accuracy or the shortening of TTFF when outputting the first positioning result depending on the reception environment. The purpose is to do.

  A first invention for solving the above-described problem is to receive a satellite signal transmitted from a positioning satellite, perform a positioning calculation of a current position based on the received satellite signal, and output a positioning output first after starting the positioning. An initial positioning output position calculation determination method for determining a positioning position to be performed, a positioning processing step for performing a positioning calculation based on a received satellite signal and calculating a positioning position, and the positioning processing step by the positioning processing step A repeat count variable step for changing the number of repetitions of the positioning process, and the positioning position finally calculated when the positioning process by the positioning process step is executed for the number of repeat executions. And an initial positioning output position determination step for determining the positioning position, and the positioning processing step is performed based on the received satellite signal. A satellite set selection step for selecting a satellite set that is a combination of satellites used for processing, and for each of the selected satellite sets, a current position candidate is calculated using a satellite signal of each satellite included in the satellite set. For each of the selected satellite sets, a candidate calculation step, 1) a pseudo-range for each of the satellites in the satellite set, and 2) an approximate distance that is a distance between the satellite and the calculated current position candidate An APR value calculating step for calculating an APR value that is a sum of squares of differences, and an average for calculating the APR average value of the current positioning process by averaging the APR values of the satellite sets calculated in the APR value calculating step The current position candidate is selected from the current position candidates of the value calculation step and each of the calculated satellite sets, and the position is determined by the current positioning process. A first positioning output position having an APR average value reference number variable step for varying the number of repeated executions based on the APR average value calculated in the positioning processing step. This is a calculation determination method.

According to a ninth aspect of the present invention, there is provided a positioning device for receiving a satellite signal transmitted from a positioning satellite and performing a positioning calculation of a current position based on the received satellite signal, wherein the positioning is based on the received satellite signal. A positioning processing unit that executes a positioning process that performs a calculation to calculate a positioning position, a repetition number variable unit that varies the number of times the positioning process is repeatedly executed by the positioning processing unit, and the positioning process by the positioning processing unit includes the positioning process. An initial positioning output position determination unit that determines a positioning position that is finally calculated as a positioning position to be output first when the number of repeated executions is performed, and the positioning processing unit is received A satellite set selection unit that selects a satellite set that is a combination of satellites used for the current positioning process based on the satellite signal, and each of the selected satellite sets is included in the satellite set. A current position candidate calculation unit that calculates a current position candidate using a satellite signal of a star, and for each of the selected satellite sets, 1) a pseudorange and 2) the satellite and the calculation of each satellite of the satellite set An APR value calculation unit that calculates an APR value that is a sum of squares of the difference between the approximate distance that is a distance between the current position candidates, and an APR value of each satellite set calculated by the APR value calculation unit Thus, an average value calculation unit for calculating the APR average value of the current positioning process,
A current positioning position selection unit that selectively selects a current position candidate from the calculated current position candidates of each satellite set and sets the positioning position by the current positioning process, and the repetition count variable unit Is a positioning device having an APR average value reference number variable unit that varies the number of repeated executions based on the APR average value calculated by the positioning processing unit.

  According to the first or ninth aspect, when the positioning process for calculating the positioning position is repeatedly executed for the number of times of repeated execution, the finally calculated positioning position is determined as the first positioning position for positioning output. The Further, the number of times of repeated execution is variable based on the APR average value.

The APR value of the satellite set is calculated according to the following formula (1) based on the pseudo distance ym and the approximate distance yp of each satellite included in the satellite set. The approximate distance yp of each satellite is the current position (x, y, z) calculated based on the position (X _i , Y _i , Z _i ) of the satellite and the satellite signal of each satellite included in the satellite set. Based on the above, it is calculated according to the following formula (2).

  Between the APR value and the positioning error, there is a tendency that the positioning accuracy of the satellite set is lower as the APR value is larger. The larger the APR average value, the higher the possibility that the received satellite signal includes a satellite signal affected by multipath or the like, that is, a so-called multipath environment. That is, the reception environment can be determined from the APR average value. Therefore, by changing the number of repeated executions according to the APR average value, it is possible to shorten the time TTFF required for the positioning output of the first positioning position according to the reception environment. For example, when the APR average value is large, there is a high possibility that the positioning accuracy is low due to the multipath environment. In such a case, priority is given to improving the positioning accuracy by changing the number of repeated executions so as to increase. On the other hand, when the APR average value is small, there is a high possibility that it is an open sky environment and the positioning accuracy is high. In such a case, TTFF can be shortened by changing the number of repeated executions to be small.

  As another invention, a satellite set selection step for selecting a satellite set that is a combination of satellites used for the current positioning process, and for each of the satellite sets, a satellite signal of each satellite included in the satellite set is used. A current position candidate calculating step of calculating a position candidate; an APR value calculating step of calculating an APR value of each satellite of the satellite set based on the current position candidate for each of the satellite sets; and the APR value of each of the satellite sets Average value calculating step for calculating the APR average value of the current positioning process, and selecting the current position candidate alternatively from the current position candidates of each of the satellite sets, A current positioning position selection step as a positioning position by processing, and an APR that changes the number of times the positioning process is repeatedly executed based on the APR average value An average reference number variable step, and an initial positioning output position determining step for determining the finally calculated positioning position as the first positioning position for positioning output when the positioning process is executed for the number of repeated executions. , Including the initial positioning output position calculation determination method.

  The second invention is the first positioning output position calculation determination method according to the first invention, wherein the repeat count variable step is performed at the time of the current positioning process every time the positioning process is executed by the positioning process step. This is an initial positioning output position calculation determination method that is a step of varying the number of repeated executions based on a calculated APR average value.

  The tenth aspect of the invention is the positioning device of the ninth aspect of the invention, wherein the repeat count variable unit is calculated during the current positioning process every time the positioning process is performed by the positioning processing unit. It is a positioning device that varies the number of repeated executions based on the APR average value.

  According to the second or tenth aspect of the invention, each time the positioning process is executed, the number of repeated executions is varied based on the APR average value calculated during the current positioning process. The APR average value varies for each positioning process. Therefore, each time the positioning process is executed, the number of repeated executions can be determined more appropriately by varying the number of repeated executions based on the APR average value calculated during the positioning process.

  The third invention is the first positioning output position calculation determination method according to the first or second invention, wherein the difference between the positioning position obtained by the previous positioning process in the positioning process step and the positioning position obtained by the current positioning process is as follows. However, if the predetermined short distance condition is not satisfied, the number of repetitions up to this time is reset and the number of repetitions is repeated, and if it is satisfied, the initial positioning output position includes a repetition number counting step that continues counting the number of repetitions. This is a calculation determination method.

  The eleventh invention is the positioning device of the ninth or tenth invention, wherein the distance difference between the positioning position by the previous positioning process by the positioning processing unit and the positioning position by the current positioning process is predetermined. If the short distance condition is not satisfied, the positioning device includes a repetition number counting unit that resets the number of repetitions up to this time and repeats counting the number of repetitions, and if satisfied, repeats counting the number of repetitions.

  According to the third or eleventh aspect of the present invention, when the distance difference between the positioning position by the previous positioning process and the positioning position by the current positioning process does not satisfy the predetermined short distance condition, the number of repetitions up to this time is calculated. After resetting, the counting of the number of repetitions is performed again, and when it is satisfied, the counting of the number of repetitions is continued. That is, the first positioning position is output when the number of times that the distance difference between the positioning positions continuously satisfies the short distance condition reaches the number of repeated executions. Thereby, when the variation in the positioning position along the time series becomes small, the first positioning position for positioning output is determined.

  A fourth invention is the initial positioning output position calculation determination method according to the first or second invention, wherein the current position candidate calculation step includes calculating a current position candidate and satellites of each satellite included in the satellite set. Calculating a time error using a signal, wherein the positioning processing step calculates a time error calculated when the current position candidate selected in the current positioning position selection step is calculated in the current position candidate calculation step. Having a current time error determination step in which the time error is determined by the current positioning process, and the difference between the time error by the previous positioning process by the positioning process step and the time error by the current positioning process is a predetermined approximation condition. If not satisfied, reset the number of repetitions up to this time and repeat the number of repetitions, and if satisfied, repeat counting the number of repetitions A first positioning output position calculation determination method further comprising the number counting step.

  The twelfth invention is the positioning device according to the ninth or tenth invention, wherein the current position candidate calculation unit uses a satellite signal of each satellite included in the satellite set together with calculation of the current position candidate. The positioning processing unit calculates the time error calculated when the current position candidate selected by the current positioning position selection unit is calculated by the current position candidate calculation unit. If the difference between the time error of the previous positioning process by the positioning processing unit and the time error of the current positioning process does not satisfy a predetermined approximation condition The positioning device further includes a repeat count unit that resets the repeat count up to this time, repeats the count of the repeat count, and continues to count the repeat count if it is satisfied.

  According to the fourth or twelfth invention, the time error is calculated using the satellite signals of the respective satellites included in the satellite set together with the calculation of the current position candidate, and the time error and the current positioning by the previous positioning process are calculated. If the difference from the time error due to the process does not satisfy the predetermined approximate condition, the number of repetitions up to this time is reset and the number of repetitions is counted again. If it satisfies, the counting of the number of repetitions is continued. That is, the first positioning position is output when the number of times that the difference in time error satisfies the approximate condition continuously reaches the number of repeated executions. As a result, the initial positioning position for positioning output is determined when the variation in time error along the time series becomes small.

  A fifth invention is the first positioning output position calculation determination method according to the first or second invention, wherein the current position candidate calculation step includes calculating a current position candidate and satellites of each satellite included in the satellite set. Calculating a time error using a signal, wherein the positioning processing step calculates a time error calculated when the current position candidate selected in the current positioning position selection step is calculated in the current position candidate calculation step. Includes a current time error determination step in which the current time error is determined by the current positioning process. 1) The distance difference between the positioning position by the previous positioning process by the positioning process step and the positioning position by the current positioning process is a predetermined close distance. If the distance condition is not satisfied, or 2) the difference between the time error of the previous positioning process in the positioning process step and the time error of the current positioning process is a predetermined close If either of the conditions is not met, the number of repetitions up to this time is reset and the number of repetitions is counted again. If none of the conditions is met, a repetition number counting step is performed to continue counting the number of repetitions. Further, the method includes an initial positioning output position calculation determination method.

  The thirteenth invention is the positioning device of the ninth or tenth invention, wherein the current position candidate calculation unit uses the satellite signal of each satellite included in the satellite set together with the calculation of the current position candidate. The positioning processing unit calculates the time error calculated when the current position candidate selected by the current positioning position selection unit is calculated by the current position candidate calculation unit. 1) When the difference in distance between the positioning position by the previous positioning process by the positioning processing section and the positioning position by the current positioning process does not satisfy a predetermined short distance condition. Or 2) If the difference between the time error due to the previous positioning process by the positioning processing unit and the time error due to the current positioning process does not satisfy a predetermined approximate condition, the process up to this time is repeated. Return Number again counting the number of iterations to reset that further include positioning device the number of repetitions counter to continue to count the number of repetitions in the case does not correspond to any.

  According to the fifth or thirteenth invention, along with the calculation of the current position candidate, the time error is calculated using the satellite signals of the respective satellites included in the satellite set. 1) Positioning position by previous positioning process and current time When the distance difference from the positioning position by the positioning process does not satisfy the predetermined short distance condition, or 2) The difference between the time error by the previous positioning process and the time error by the current positioning process satisfies the predetermined approximate condition If not, the number of repetitions up to this time is reset and the number of repetitions is counted again. If the number is satisfied, counting of the number of repetitions is continued. In other words, the number of times the distance difference between the positioning positions continuously satisfies the short distance condition reaches the number of repeated executions, and the number of times the difference in time error continuously satisfies the approximate condition reaches the number of repeated executions. The positioning position is output. As a result, the initial positioning position for positioning output is determined when the variation in positioning position and time error along the time series becomes small.

  According to a seventh aspect of the present invention, there is provided a computer incorporated in a positioning device that receives a satellite signal transmitted from a positioning satellite and measures a current position based on the received satellite signal, and the initial positioning of any of the above-described inventions. A program for executing an output position calculation determination method.

  According to the seventh aspect, by causing the computer to read this program and executing the calculation process, it is possible to achieve the same operational effects as the above-described initial positioning output position calculation determination method.

  The eighth invention is a computer-readable storage medium storing the program of the seventh invention.

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

  14th invention is an electronic device provided with the positioning apparatus of any of 9th-13th invention.

  According to the fourteenth aspect of the invention, an electronic device having the same operational effects as any of the ninth to fourteenth aspects of the invention is realized.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In the following, a mobile phone to which the present invention is applied will be described, but embodiments to which the present invention can be applied are not limited thereto.

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

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

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

  The oscillation circuit 22 is a crystal oscillator, for example, and generates and outputs an oscillation signal having a predetermined oscillation frequency.

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

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

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

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

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

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

  In the baseband processing, the CPU 31 decodes the navigation message included in the supplemented / tracked GPS satellite signal, and calculates the current position based on the orbit information and time information of the GPS satellite included in the decoded navigation message. That is, from the difference between the transmission time of the GPS satellite signal from each GPS satellite and the reception time of the GPS satellite signal at the GPS receiver, the position of each GPS satellite at the time of transmission of the GPS satellite signal and each GPS from the GPS receiver Calculate the pseudorange to the satellite. Then, a simultaneous equation having four unknowns including the current position and the time error between the GPS satellite and the GPS receiver is set, and the current position is calculated by solving the simultaneous equations. At this time, the current position can be calculated by receiving GPS satellite signals from at least four or more GPS satellites. This is because four coordinate values (x, y, z) of the current position, which is a three-dimensional position, and a time error T between the GPS satellite and the GPS receiver are set as unknowns.

Specifically, the CPU 31 repeatedly performs a positioning process for calculating the current position P at a predetermined time interval (for example, every second). In the positioning process, a “satellite set” that is a combination of four or more GPS satellites is selected from the captured GPS satellite signals. For example, if eight GPS satellites signals captured, satellite set 163 pieces _{(= 8 C 8 + 8 C} 7 + 8 C 6 + 8 C 5 + 8 C 4) is selected. Next, for each selected satellite set, a positioning calculation using, for example, the least square method is performed to calculate the current position candidate and the time error candidate of the own aircraft. Then, for example, one of these satellite sets is selected according to a predetermined evaluation criterion, and the current position candidate of the selected satellite set (selected satellite set) is determined as the current current position P. The time error candidate is determined as the current time complementary error T. The evaluation standard is realized by a known method such as a position accuracy degradation index PDOP (Position Dilution of Precision) based on the geometric arrangement of GPS satellites in the satellite set or a method based on the signal strength of each GPS satellite signal. Here, out of all the satellite sets generated from the captured GPS satellites, for example, dozens of satellite sets including 6 or more GPS satellites are extracted, and the positioning position and time for the extracted satellite sets are extracted. The error may be determined.

  In the present embodiment, immediately after the start of positioning (first positioning), the positioning process is repeated one or more times, and the current position P calculated in the last positioning process is output (positioning output) as the first positioning position. . After the first positioning position is determined and output, the calculated current position P is output as a positioning position (positioning output) for each positioning process.

  That is, in the first positioning, when the current position P and time error T are calculated in each positioning process, the difference (positional difference) between the calculated current position P and the current position P0 calculated in the previous positioning process. ΔP is calculated. If the calculated position difference ΔP satisfies a predetermined short distance condition (for example, 200 [m] or less), the position counter is updated (counted up) to a value obtained by adding “1”. If not, clear the position counter to zero. Here, the position counter is cleared to zero at the start of positioning. That is, this count value (position count value) counts the number of times that the position difference ΔP is continuously equal to or less than a predetermined value.

  Further, a difference (time difference) ΔT between the current time error T and the time error T0 calculated in the previous positioning process is calculated. If the calculated time difference ΔT satisfies a predetermined approximation condition (for example, 0.02 [seconds] or less), the time counter is updated (counted up) to a value obtained by adding “1”, and the approximation condition is set. If not satisfied, the time counter is cleared to zero. Here, the time counter is cleared to zero at the start of positioning. That is, this count value (time count value) counts the number of times that the time difference ΔT is continuously less than or equal to a predetermined value.

  Further, the position threshold value and the time threshold value are determined. Specifically, a predetermined reference threshold value (for example, “3”) is increased or decreased by an amount of change corresponding to the APR average value in the current positioning process to determine each of the position threshold value and the time threshold value. The APR average value is an average value of the recursive residual APR (APR value) of each satellite set selected in the current positioning process.

  Then, each count value and each threshold value are compared, and if the position count value reaches the position threshold value and the time count value reaches the time threshold value, the current current position P is determined as the first positioning position and output ( Positioning output). On the other hand, if the position count value has not reached the position threshold value or the time count value has not reached the time threshold value, the next positioning process is performed.

式（１）において、「Ｎ」は、当該衛星組に含まれるＧＰＳ衛星の個数（衛星数）であり、「ｉ（＝１，２，・・・，Ｎ）」は、これらのＧＰＳ衛星のうちのｉ番目のＧＰＳ衛星を表す。また、「ｙｍ_ｉ」は、ｉ番目のＧＰＳ衛星の擬似距離である。また、「ｙｐ_ｉ」は、ｉ番目のＧＰＳ衛星の位置（Ｘ_ｉ，Ｙ_ｉ，Ｚ_ｉ）と、測位演算により得られた現在位置（ｘ，ｙ，ｚ）との間の距離（近似距離）であり、次式（２）で与えられる。

即ち、ＡＰＲ値は、当該衛星組のＧＰＳ衛星それぞれの擬似距離ｙｍと近似距離ｙｐとの差分の二乗和として与えられる。 The recursive residual APR (APR value) for a certain satellite set is given by the following equation (1).

In Expression (1), “N” is the number of GPS satellites (number of satellites) included in the satellite set, and “i (= 1, 2,..., N)” is the number of these GPS satellites. It represents the i-th GPS satellite. “Ym _i ” is a pseudorange of the i-th GPS satellite. “Yp _i ” is a distance (approximate distance) between the position (X _i , Y _i , Z _i ) of the i-th GPS satellite and the current position (x, y, z) obtained by the positioning calculation. ) And is given by the following equation (2).

That is, the APR value is given as the sum of squares of the difference between the pseudo distance ym and the approximate distance yp of each GPS satellite of the satellite set.

  FIG. 2 shows an example of an experimental result showing the relationship between the APR value and the positioning accuracy. FIG. 2A shows the experimental results in the “multipath environment”, and FIG. 2B shows the experimental results in the “open sky environment”. However, the current position of the aircraft is known. In FIG. 2, the results of each positioning process are shown in time series from the start of positioning in the reception environments of the multipath environment and the open sky environment. As a result of the positioning process, the satellite set (selected satellite set) selected in the positioning process, the APR average value, and the horizontal error are shown. The APR average value is an average value of the APR values of each satellite set selected in the positioning process. The “horizontal error” is a difference in the horizontal direction between the known position of the own device and the current position P calculated in the positioning process. In any reception environment, the Z count is decoded in the fifth positioning process. That is, the positioning process before the fourth time is before the decoding of the Z count, and the positioning process after the fifth time is after the decoding of the Z count.

  According to FIG. 2, it can be determined that the larger the APR average value, the larger the horizontal error, that is, the lower the positioning accuracy, between the APR average value and the horizontal error.

  Further, when comparing the multipath environment and the open sky environment, both the APR value and the horizontal error are larger in the multipath environment than in the open sky environment. That is, the reception environment can be determined from the APR average value. That is, the larger the APR average value, the higher the possibility of a multipath environment, while the smaller the APR average value, the higher the possibility of an open sky environment.

  Also, when comparing before and after the decoding of the Z count in each reception environment, in the multipath environment, the horizontal error is large and the variation in the value is large before the decoding of the Z count. As the horizontal error becomes smaller, the variation of the value becomes smaller. Further, after decoding of the Z count, the APR average value decreases as the horizontal error decreases. That is, in a multipath environment, it is desirable to output the first positioning position after the Z count is decoded.

  On the other hand, in the open sky environment, there is no significant change in the horizontal error regardless of before and after the decoding of the Z count, the variation in the value is small, and the change in the horizontal error is small. Also, the APR average value is small and the variation in the value is small regardless of before and after the decoding of the Z count. That is, in the open sky environment, it can be determined that the first positioning position may be output even before the Z count is decoded.

  Therefore, in the present embodiment, the timing for outputting the first positioning position is determined from the relationship between the APR average value and the positioning accuracy. That is, it is determined whether or not the variation in the current position P has become small depending on whether or not the position count value has reached the position threshold value, and the variation in the time error T has become small because the time count value has reached the time threshold value. It is determined whether or not. The initial positioning position is output at the timing when it is determined that both the variation in the current position P and the variation in the time error T are small.

  In addition, the position threshold and the time threshold are determined based on the APR average value in each positioning process. For this reason, even if it is moving, the output timing of the first positioning position is changed according to the reception environment in the current (current) positioning process. That is, when the APR average value is large and the possibility of a multipath environment is high, both the position threshold and the time threshold are set large, and the timing for outputting the first positioning position is delayed. In addition, when the APR average value is small and the possibility of an open sky environment is high, both the position threshold and the time threshold are set small, and the timing for outputting the first positioning position is advanced.

  Returning to FIG. 1, the ROM 32 is a system program for the CPU 31 to control each part of the baseband processing circuit unit 30 and the RF receiving circuit unit 21, various programs and data for realizing various processes including baseband processing, and the like. Is remembered. FIG. 3 shows an example of the configuration of the ROM 32. According to FIG. 3, the ROM 32 stores a baseband processing program 321, a count-up condition table 322, and a threshold value change condition table 323.

  The count-up condition table 322 is a data table that defines conditions for increasing (counting up) the position count and the time count. FIG. 4 shows an example of the data configuration of the count-up condition table 322. According to FIG. 4, the count-up condition table 322 stores conditions for increasing (counting up) the count value for each of the position counter and the time counter. That is, for the position counter, the magnitude of the position difference ΔP is determined as a short distance condition so that the variation in the current position P in each positioning process can be regarded as “small”. For the time counter, as an approximate condition, the time difference ΔT is determined so that the variation in the time error T in each positioning process can be regarded as “small”.

  The threshold change condition table 323 is a data table that defines conditions for changing the position threshold and the time threshold. FIG. 5 shows an example of the data configuration of the threshold value change condition table 323. According to FIG. 5, the threshold change condition table 323 stores a threshold change condition 323a and a threshold change amount 323b in association with each other. The change condition 323a stores condition values for the number of satellites, the PDOP value, and the APR average value. As described above, the smaller the APR average value, the higher the possibility of an open sky environment, and the larger the APR average value, the higher the possibility of a multipath environment. For this reason, when the APR average value is small, the change amount is set to a negative value and the threshold value is lowered. On the contrary, when the APR average value is large, the change amount is set to a positive value and the threshold value is increased. ing. In general, the positioning accuracy tends to be higher as the PDOP value is smaller. For this reason, the PDOP value is set so that the change amount is a negative value and the threshold value is lowered when the PDOP value is large. In general, the larger the number of satellites, the smaller the PDOP value and the higher the positioning accuracy. For this reason, when the number of satellites is large, the amount of change is set to a negative value so that the threshold value is lowered.

  The RAM 33 is used as a work area of the CPU 31, and temporarily stores programs and data read from the ROM 32, calculation results executed by the CPU 31 according to various programs, and the like. FIG. 6 shows an example of the configuration of the RAM 33. According to FIG. 6, the RAM 33 stores satellite position data 331, satellite set data 332, and positioning result data 333.

  The satellite position data 331 is data about the position of the GPS satellite captured in each positioning process. FIG. 7 shows an example of the data configuration of the satellite position data 331. According to FIG. 7, the satellite position data 331 stores, for each captured GPS satellite 331a, the satellite position 331b calculated based on the GPS satellite signal in association with each other.

  The satellite set data 332 is data on the satellite set selected in each positioning process. FIG. 8 shows an example of the data configuration of the satellite set data 332. According to FIG. 8, the satellite set data 332 includes, for each selected satellite set 332a, the GPS satellite 332b, current position candidate 332c, time error candidate 332d, number of satellites 332e, PDOP included in the satellite set. A value 332f and an APR value 332g are stored in association with each other.

  The positioning result data 333 is calculation result data in each positioning process. FIG. 9 shows an example of the data structure of the positioning result data 333. According to FIG. 9, the positioning result data 333 includes the positioning time 333a, the selected satellite set 333b, the positioning position 333c, the time error 333d, the number of satellites 333e, and the PDOP for each positioning process from the start of positioning. The value 333f and the APR average value 333g are stored in association with each other.

  The counter data 334 stores current counter values of the position counter and the time counter. Data 335 stores a current position threshold and a time threshold.

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

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

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

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

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

  According to FIG. 10, the CPU 31 first clears the position counter and the time counter to zero as an initial setting (step A1). Next, a positioning calculation process is performed to calculate the current current position P and time error T (step A3).

  FIG. 11 is a flowchart for explaining the flow of the positioning calculation process. According to FIG. 11, the CPU 31 calculates satellite information including the position of each GPS satellite based on the captured GPS satellite signal (step B1). Next, a satellite set composed of four or more GPS satellites is selected based on the captured GPS satellite signals (step B3), and a loop A process is performed for each selected satellite set.

  In the loop A, a current position candidate and a time error candidate are calculated by performing a positioning calculation using, for example, the least square method based on the position of each GPS satellite of the target satellite set (step B5). Further, the number of GPS satellites (the number of satellites) included in the target satellite set is calculated (step B7). Based on the calculated current position candidate, the PDOP value of the target satellite set is calculated (step B9), and further, the APR value is calculated (step B11). Loop A is performed in this way.

  When the loop A for all the satellite sets is completed, an APR average value that is an average value of the APR values of each satellite set is calculated (step B13). Further, an evaluation process for evaluating each satellite set using a PDOP value or the like is performed (step B15). Then, one of the satellite sets is selected based on the evaluation result, the current position candidate of the selected satellite set is determined as the current positioning position, and the time error candidate of the satellite set is determined as the current time error ( Step B17). When the above processing is performed, the positioning calculation processing is terminated.

  When the positioning calculation process is completed, the CPU 31 subsequently performs a count process (step A5).

  FIG. 12 is a flowchart for explaining the flow of the counting process. According to FIG. 12, the CPU 31 calculates a difference (positional difference) ΔP between the previous positioning position and the current positioning position (step C1). If the calculated position difference ΔP satisfies the count-up condition (that is, a predetermined value or less) (step C3: YES), the position counter is updated to a value obtained by adding “1” (step C5), and the count-up condition is changed. If not satisfied (step C3: NO), the position counter is cleared to zero (step C7).

  Also, a difference (time difference) ΔT between the previous time error and the current time error is calculated (step C9). If the calculated time difference ΔT satisfies the count-up condition (that is, a predetermined value or less) (step C11: YES), the time counter is updated to a value obtained by adding “1” (step C13), and the count-up condition is changed. If not satisfied (step C11: NO), the time counter is cleared to zero (step C15). When the above process is performed, the count process is terminated.

  When the counting process ends, the CPU 31 subsequently performs a threshold value changing process (step A7).

  FIG. 13 is a flowchart for explaining the flow of the threshold value changing process. According to FIG. 13, as an initial setting, the CPU 31 sets both the position threshold value and the time threshold value to the reference threshold value “3” (step D <b> 1). Next, with reference to the threshold change condition table 323, the position threshold and the time threshold are changed based on the number of satellites (step D3). Further, the position threshold and the time threshold are changed based on the PDOP value (step D5), and further, the position threshold and the time threshold are changed based on the APR average value (step D7). When the above processing is performed, the threshold value changing process is terminated.

  When the threshold value changing process ends, the CPU 31 subsequently compares the position count value with the position threshold value, and the time count value and the time threshold value. If the position count value is less than the position threshold value (step A9: NO) or the time count value is less than the time threshold value (step A11: NO), the process returns to step A3 to perform the next positioning. On the other hand, if the position count value is equal to or greater than the position threshold value (step A9: YES) and the time count value is equal to or greater than the time threshold value (step A11: YES), the current current position P is determined as the first positioning position and output. (Step A13). This is the first positioning.

  When the first positioning is completed, the second and subsequent positioning is started. That is, positioning calculation processing (see FIG. 11) is performed (step A15), and the calculated current position P is output as a positioning result (step A17). Next, it is determined whether or not the positioning is to be ended. If the positioning is not to be ended (step A19: NO), the process returns to step A15 to perform the next positioning. If the positioning is finished (step A19: YES), the baseband processing is finished.

[Modification]
As mentioned above, although one embodiment to which the present invention is applied has been described, the applicable embodiment of the present invention is not limited to the above-described embodiment, and of course can be appropriately changed without departing from the spirit of the present invention. is there.

(A) Decoding of Z count For example, after the Z count is decoded, the variation in the time error T is almost zero even in a multipath environment. For this reason, when the Z count is decoded, the current position P may be determined as the positioning position and output without comparing the count value with the threshold value.

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

(C) Positioning device In the above-described embodiment, a mobile phone, which is a kind of electronic device provided with a positioning device, has been described. For example, a portable navigation device, an in-vehicle navigation device, a PDA (Personal Digital Assistants) The present invention can be similarly applied to other electronic devices such as wristwatches.

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

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

The internal block diagram of a mobile telephone. An example of the experimental result which shows the relationship between an ARP average value and a positioning error. The block diagram of ROM. The data structural example of a count-up condition table. The data structural example of a threshold value change condition table. The block diagram of RAM. Data configuration example of satellite position data. Data configuration example of satellite set data. The example of a data structure of positioning result data. The flowchart of a baseband process. The flowchart of the positioning calculation process performed during a baseband process. The flowchart of the count process performed during a baseband process. The flowchart of the threshold value change process performed during a baseband process.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Mobile phone, 20 GPS receiving part, 21 RF receiving circuit part, 22 Oscillator circuit, 30 Baseband processing circuit part, 31 CPU, 32 ROM, 321 Baseband processing program, 322 Count up condition table, 323 Threshold change condition table, 33 RAM, 331 satellite position data, 332 satellite set data, 333 positioning result data, 334 counter data, 335 threshold data

Claims (14)

Initial positioning output position calculation determination method for receiving a satellite signal transmitted from a positioning satellite, performing a positioning calculation of the current position based on the received satellite signal, and determining a positioning position for first positioning output after positioning start Because
A positioning process step for performing a positioning process for calculating a positioning position by performing a positioning calculation based on a received satellite signal;
A repeat count variable step of varying the repeat execution count of the positioning process by the positioning process step;
When the positioning process by the positioning process step is executed for the number of times of repeated execution, an initial positioning output position determining step for determining a positioning position finally calculated as an initial positioning position for positioning output;
Including
The positioning processing step includes
A satellite set selection step of selecting a satellite set that is a combination of satellites used for the current positioning process based on the received satellite signals;
For each selected satellite set, a current position candidate calculating step for calculating a current position candidate using the satellite signal of each satellite included in the satellite set;
For each of the selected satellite sets, the sum of squares of the difference between 1) the pseudorange of each satellite of the satellite set and 2) the approximate distance that is the distance between the satellite and the calculated current position candidate An APR value calculating step for calculating an APR value;
An average value calculating step of calculating an APR average value of the current positioning process by averaging the APR values of the satellite sets calculated in the APR value calculating step;
A current positioning position selection step of selecting a current position candidate alternatively from the calculated current position candidates of each satellite set, and setting it as a positioning position by the current positioning process;
Have
The repetition number variable step includes an APR average value reference number variable step for varying the number of repetition executions based on the APR average value calculated in the positioning processing step.
Initial positioning output position calculation determination method. The initial positioning output position calculation determination method according to claim 1,
The repeat count variable step is a step of changing the repeat execution count based on the APR average value calculated at the time of the current positioning process every time the positioning process in the positioning process step is executed. Decision method. An initial positioning output position calculation determination method according to claim 1 or 2,
If the distance difference between the positioning position of the previous positioning process at the positioning process step and the positioning position of the current positioning process does not satisfy the predetermined short-distance condition, the number of repetitions is reset by resetting the number of repetitions up to this time. An initial positioning output position calculation determination method including a repetition count counting step in which counting is repeated and satisfied when counting is repeated. An initial positioning output position calculation determination method according to claim 1 or 2,
The current position candidate calculation step is a step of calculating a time error using a satellite signal of each satellite included in the satellite set, together with calculation of a current position candidate.
In the positioning process step, the current time candidate, which is the time error calculated when the current position candidate selected in the current positioning position selection step is calculated in the current position candidate calculation step, is set as the time error due to the current positioning process. An error determination step;
If the difference between the time error due to the previous positioning process in the positioning process step and the time error due to the current positioning process does not satisfy the predetermined approximate condition, the number of repetitions is counted by resetting the number of repetitions up to this time. And further includes a repeat count step to continue counting the repeat count if redoed and satisfied.
Initial positioning output position calculation determination method. An initial positioning output position calculation determination method according to claim 1 or 2,
The current position candidate calculation step is a step of calculating a time error using a satellite signal of each satellite included in the satellite set, together with calculation of a current position candidate.
In the positioning process step, the current time candidate, which is the time error calculated when the current position candidate selected in the current positioning position selection step is calculated in the current position candidate calculation step, is set as the time error due to the current positioning process. An error determination step;
1) When the distance difference between the positioning position by the previous positioning process at the positioning process step and the positioning position by the current positioning process does not satisfy a predetermined short distance condition, or 2) The previous positioning process by the positioning process step If the difference between the time error due to this time and the time error due to the current positioning process does not satisfy the predetermined approximate condition, the number of repetitions up to this time is reset and the number of repetitions is counted again. If not, it further includes a repeat count step for continuing the repeat count.
Initial positioning output position calculation determination method. A satellite set selection step for selecting a satellite set that is a combination of the satellites used for the positioning process of this time;
For each of the satellite sets, a current position candidate calculation step of calculating a current position candidate using the satellite signal of each satellite included in the satellite set;
An APR value calculating step for calculating an APR value of each satellite of the satellite set based on the current position candidate for each of the satellite sets;
An average value calculating step of calculating an APR average value of the current positioning process by averaging the APR values of the satellite sets;
A current positioning position selection step of selecting a current position candidate alternatively from the current position candidates of each of the satellite sets and setting the positioning position by the current positioning process;
An APR average value reference number variable step for changing the number of times the positioning process is repeatedly executed based on the APR average value;
When the positioning process is executed for the number of times of repeated execution, an initial positioning output position determination step for determining a positioning position finally calculated as an initial positioning position for positioning output;
The first positioning output position calculation determination method including.   The first positioning according to any one of claims 1 to 6, wherein a computer incorporated in a positioning device that receives a satellite signal transmitted from a positioning satellite and measures a current position based on the received satellite signal. A program for executing the output position calculation determination method.   A computer-readable storage medium storing the program according to claim 7. A positioning device that receives a satellite signal transmitted from a positioning satellite and performs a positioning calculation of a current position based on the received satellite signal,
A positioning processing unit that performs a positioning process to calculate a positioning position by performing a positioning calculation based on a received satellite signal;
A repetition number variable unit that varies the number of repetitions of the positioning process by the positioning processing unit;
When the positioning processing by the positioning processing unit is executed for the number of times of repeated execution, an initial positioning output position determination unit that determines a positioning position that is finally calculated as a positioning position for which positioning output is performed first;
With
The positioning processing unit
A satellite set selection unit that selects a satellite set that is a combination of satellites used for the current positioning process based on the received satellite signals;
For each selected satellite set, a current position candidate calculation unit that calculates a current position candidate using satellite signals of each satellite included in the satellite set;
For each of the selected satellite sets, the sum of squares of the difference between 1) the pseudorange of each satellite of the satellite set and 2) the approximate distance that is the distance between the satellite and the calculated current position candidate An APR value calculation unit for calculating a certain APR value;
An average value calculating unit that calculates an APR average value of the current positioning process by averaging the APR values of the satellite sets calculated by the APR value calculating unit;
A current position selection unit that selects a current position candidate alternatively from the calculated current position candidates of each satellite set, and sets the current position as a positioning position by the current positioning process;
Have
The repeat count variable section includes an APR average value reference count variable section that varies the repeat execution count based on the APR average value calculated by the positioning processing section.
Positioning device. The positioning device according to claim 9, wherein
The repeat count variable unit is a positioning device that varies the repeat execution count based on the APR average value calculated during the current positioning process every time the positioning process is performed by the positioning processing unit. The positioning device according to claim 9 or 10,
If the distance difference between the positioning position of the previous positioning process by the positioning processing section and the positioning position of the current positioning process does not satisfy the predetermined short-distance condition, the number of repetitions is reset by resetting the number of repetitions up to this time. A positioning device provided with a repeat count section that repeats counting and continues counting the number of repetitions when the count is satisfied. The positioning device according to claim 9 or 10,
The current position candidate calculation unit calculates a time error using a satellite signal of each satellite included in the satellite set, along with calculation of a current position candidate,
The positioning processing unit uses a time error calculated when the current position candidate selected by the current positioning position selection unit is calculated by the current position candidate calculation unit as a time error due to the current positioning process. An error determination unit;
If the difference between the time error due to the previous positioning process by the positioning processing unit and the time error due to the current positioning process does not satisfy the predetermined approximate condition, the number of repetitions is counted by resetting the number of repetitions up to this time. If it meets again, it further includes a repeat count section that continues counting the repeat count,
Positioning device. The positioning device according to claim 9 or 10,
The current position candidate calculation unit calculates a time error using a satellite signal of each satellite included in the satellite set, along with calculation of a current position candidate,
The positioning processing unit uses a time error calculated when the current position candidate selected by the current positioning position selection unit is calculated by the current position candidate calculation unit as a time error due to the current positioning process. An error determination unit;
1) When the distance difference between the positioning position by the previous positioning process by the positioning processing section and the positioning position by the current positioning process does not satisfy a predetermined short distance condition, or 2) The previous positioning process by the positioning processing section If the difference between the time error due to this time and the time error due to the current positioning process does not satisfy the predetermined approximate condition, the number of repetitions up to this time is reset and the number of repetitions is counted again. If it is not applicable, it further includes a repetition number counting unit that continues counting the number of repetitions.
Positioning device.   The electronic device provided with the positioning apparatus as described in any one of Claims 9-13.

Images