JP2009264811A - Location measuring method, program and location measuring apparatus - Google Patents

Abstract

An object of the present invention is to efficiently receive a positioning signal by appropriately setting a search range of the positioning signal.
A first pseudo distance calculated by regarding a positioning base position as a position of a mobile phone (1)
The position relative to the positioning base position based on the difference between the first integer part) and the second pseudo distance (second integer part) calculated based on the time difference between the transmission time and the reception time of the GPS satellite signal The error is corrected. Then, a search range of the GPS satellite signal is set using the position error, and positioning is performed by receiving the GPS satellite signal based on the search range.
[Selection] Figure 1

Description

The present invention relates to a positioning method in which a positioning device performs positioning by receiving a positioning signal from a positioning satellite that transmits a positioning signal periodically with a transmission time.

GPS (Global Positioning System) is a positioning system that uses positioning signals.
Is widely known, and is used in positioning devices built in mobile phones, car navigation devices, and the like. In GPS, the values of four parameters, the three-dimensional coordinate value indicating the position of the aircraft and the clock error, are calculated based on information such as the positions of a plurality of GPS satellites and the pseudoranges from each GPS satellite to the aircraft. The current position of the aircraft is measured by performing the required positioning calculation.

As a technique related to GPS, for example, Patent Document 1 discloses a positioning calculation of this time using a position error included in a positioning position obtained by the previous positioning calculation (hereinafter referred to as “previous positioning position”). A technique for determining a base position (initial position) to be used for the above is disclosed. The position error is the time difference between the previous positioning time and the current time, and the predetermined maximum speed of the positioning device (
For example, a method of obtaining by multiplying by “200 km / h”) is used.
JP 2006-71460 A

In positioning by GPS, it is necessary to acquire / extract navigation data contained in a GPS satellite signal by performing acquisition of a GPS satellite (also referred to as acquisition of a GPS satellite signal) as preprocessing of the positioning calculation. Specifically, a frequency and phase search range is set, and a GPS satellite is captured by performing a frequency and phase search within the search range.

The frequency search range is generally set wide when the position error is large, and narrow when the position error is small. According to the conventional method, the longer the time has elapsed since the previous positioning, the larger the position error is calculated, and the wider the search range is set. If the signal strength of the GPS satellite signal is weak, the GPS satellite may not be captured unless the search is repeated several times within the set search range, but the search range is set wide. That alone has the problem that it takes a long time to capture a GPS satellite.

Further, when the positioning device moves at a speed exceeding the assumed maximum moving speed, the opposite problem occurs. In other words, the GPS satellite cannot be captured within the set search range because the movement exceeds the set position error.

  The present invention has been made in view of the above-described problems.

A first invention for solving the above problems is a positioning method in which a positioning device receives a positioning signal from a positioning satellite that transmits a positioning signal periodically with a transmission time and performs positioning. And calculating a first pseudo distance that regards a given positioning base position as the position of the positioning device, and a second pseudo distance based on a time difference between the transmission time and the reception time at the time of reception. Calculating a position error with respect to the given positioning base position, and correcting the position error based on a difference between the first pseudo distance and the second pseudo distance. A positioning method including: setting a signal search range when receiving the positioning signal using the position error; and receiving the positioning signal based on the signal search range and performing positioning It is.

Further, as another invention, a positioning device that performs positioning by receiving the positioning signal from a positioning satellite that transmits the positioning signal by periodically transmitting the transmission time, the receiving device receiving the transmission time A detecting unit for detecting, a first calculating unit for calculating a first pseudo distance in which a given positioning base position is regarded as a position of the positioning device, a transmission time detected by the detecting unit, and reception at the time of reception A second calculation unit that calculates a second pseudo distance based on a time difference from the time; a position error setting unit that sets a position error with respect to the given positioning base position; the first pseudo distance and the second A position error correction unit that corrects the position error based on the difference from the pseudo distance, a signal search range setting unit that sets a signal search range when receiving the positioning signal using the position error, The positioning based on the signal search range A positioning section for performing positioning by receiving the signal, may constitute a positioning device provided with a.

According to the first invention and the like, the calculation is based on the first pseudo distance calculated by regarding the given positioning base position as the position of the positioning device, and the time difference between the transmission time and the reception time of the positioning signal. Second
The position error with respect to the positioning base position is corrected based on the difference from the pseudo distance. And
The signal search range of the positioning signal is set using the position error, and positioning is performed by receiving the positioning signal based on the signal search range.

If the difference between the first pseudo distance and the second pseudo distance calculated by different calculation methods is small, the first pseudo distance in which the positioning base position is regarded as the position of the positioning device has a certain reliability (accuracy). Therefore, for example, it is possible to correct the position error to a smaller value.
On the other hand, if the difference between the first pseudo distance and the second pseudo distance is large, reliability (accuracy) is not recognized in the first pseudo distance in which the positioning base position is regarded as the position of the positioning device. For example, the position error can be corrected to a larger value.

Further, as a second invention, in the positioning method according to the first invention, the setting of the position error is to set the position error wider as the elapsed time from the last positioning is longer. And correcting the position error is preset as a position error when the approximate condition is satisfied when a difference between the first pseudo distance and the second pseudo distance satisfies a predetermined approximate condition. A positioning method including correcting the position error to the pseudo-range approximation position error may be configured.

According to the second aspect of the invention, the position error is set wider as the elapsed time from the last positioning is longer. Further, when the difference between the first pseudo distance and the second pseudo distance satisfies a predetermined approximation condition, a position error is added to the position error for pseudo distance approximation set in advance as a position error when the approximation condition is satisfied. Is corrected. For example, if the position error is large even though the first pseudo distance and the second pseudo distance are approximate, the position error setting itself is considered to be incorrect, so the position error is corrected to a smaller value. It is preferable.

According to a third aspect of the present invention, in the positioning method according to the second aspect of the invention, the correction of the position error is based on the fact that the difference between the first pseudo distance and the second pseudo distance is the predetermined approximate condition. And the position error is smaller than the position error for pseudo distance approximation, the position error is corrected based on the difference between the first pseudo distance and the second pseudo distance. You may comprise the positioning method containing.

According to the third aspect, when the difference between the first pseudo distance and the second pseudo distance does not satisfy the predetermined approximation condition and the position error is smaller than the position error for pseudo distance approximation, The position error is corrected based on the difference between the pseudo distance and the second pseudo distance. In such a case, since the position error is considered to be incorrect, it is preferable to correct the position error to a value proportional to the difference between the first pseudo distance and the second pseudo distance, for example.

According to a fourth aspect of the present invention, in the positioning method of the second or third aspect of the invention, the positioning signal is encoded with a pseudo-noise code, and the correction of the position error is performed by the pseudo-noise code. A positioning method may be configured in which the correction is performed with the predetermined approximate condition being within a distance corresponding to a code length of.

According to the fourth aspect of the invention, the positioning signal is encoded by the pseudo noise code, and the position error is corrected under the approximation condition that it is within a distance corresponding to the code length of the pseudo noise code.

Further, as a fifth invention, the positioning method according to any one of the first to fourth inventions, wherein the transmission time from any one of the positioning satellites is received. , Calculating the first pseudo distance, and calculating the second pseudo distance include calculating a pseudo distance related to the positioning satellite that has transmitted the received transmission time. And setting the signal search range includes positioning the frequency signal search range when receiving a positioning signal from a positioning satellite other than the positioning satellite that has transmitted the received transmission time. A method may be configured.

According to the fifth aspect of the present invention, it is detected that the transmission time from any one of the plurality of positioning satellites is received, and the pseudo distance related to the positioning satellite that has transmitted the received transmission time is Calculated. And the signal search range of the frequency at the time of receiving the positioning signal from positioning satellites other than the positioning satellite which transmitted the received transmission time is varied. Therefore, it is possible to variably set the signal search range of other positioning satellites based on the difference between the first pseudorange and the second pseudorange calculated for one positioning satellite.

As a sixth invention, a program for causing a computer incorporated in a positioning device to execute the positioning method of any of the first to fifth inventions may be configured.

Hereinafter, an example of an embodiment suitable for the present invention will be described with reference to the drawings. In the following, a mobile phone is taken as an example of an electronic device equipped with a positioning device, and a GPS (Gl
Although the case where the obal positioning system is used will be described, embodiments to which the present invention can be applied are not limited thereto.

1. Functional Configuration FIG. 1 is a block diagram showing a functional configuration of a mobile phone 1 according to this embodiment. The mobile phone 1 includes a GPS antenna 5, a GPS receiver 10, and a host CPU (Central Proc
essing unit) 30, operation unit 40, display unit 50, mobile phone antenna 60, mobile phone radio communication circuit unit 70, ROM (Read Only Memory) 80, RAM (Random Acc)
ess Memory) 90.

The GPS antenna 5 is an RF (Radi) including a GPS satellite signal transmitted from a GPS satellite.
o Frequency) An antenna that receives a signal, and outputs the received signal to the GPS receiver 10. The GPS satellite signal is a PRN (Pseudo Ran) that is a kind of spreading code that differs for each satellite.
dom Noise) code 1.57542 [GH modulated directly by spread spectrum method
z]. 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 10 is based on the signal output from the GPS antenna 5, and the mobile phone 1
This is a positioning circuit that measures the current position of the GPS, and is a functional block corresponding to a so-called GPS receiver. The GPS receiving unit 10 includes an RF (Radio Frequency) receiving circuit unit 11 and a baseband processing circuit unit 20. The RF receiving circuit unit 11 and the baseband processing circuit unit 20 can be manufactured as separate LSIs (Large Scale Integration) or can be manufactured as one chip.

The RF receiving circuit unit 11 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 5, the RF signal is down-converted to an intermediate frequency signal (hereinafter referred to as an "IF (Intermediate Frequency) signal"), After the IF signal is amplified, it is converted into a digital signal by an A / D converter and output to the baseband processing circuit unit 20.

The baseband processing circuit unit 20 performs correlation processing on the IF signal output from the RF receiving circuit unit 11 to capture and extract GPS satellite signals, decodes the data, and extracts navigation messages, time information, and the like. This is a circuit unit that performs positioning calculation. The baseband processing circuit unit 20
A CPU 21 as a processor, a ROM 23 and a RAM 25 as memories, and a clock unit 27 that measures time are configured. Note that the clock unit 27 may time the hour, minute, second, or may count the GPS week number and the TOW (Time Of Week) count value in the same manner as the Z count.

The host CPU 30 is a processor that comprehensively controls each unit of the mobile phone 1 according to various programs such as a system program stored in the ROM 80. Host CPU
30 displays on the display unit 50 a navigation screen in which the output position input from the CPU 21 is plotted.

The operation unit 40 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 30. This operation unit 40
Through the operation, various instructions such as a call request, a mail transmission / reception request, and a GPS activation request are input.

The display unit 50 is composed of an LCD (Liquid Crystal Display) or the like, and the host CPU 3
It is a display device that performs various displays based on display signals input from zero. The display unit 50 includes
A navigation screen, time information, and the like are displayed.

The cellular phone antenna 60 is an antenna that transmits and receives cellular phone radio signals and various data to and from a radio base station installed by a communication service provider of the cellular phone 1.

The cellular phone wireless communication circuit unit 70 is a cellular phone communication circuit unit configured by an RF conversion circuit, a baseband processing circuit, and the like, and performs modulation and demodulation of the cellular phone radio signal, thereby enabling communication and mailing. Realize transmission / reception of

The ROM 80 is a read-only nonvolatile storage device, and stores a system program for the host CPU 30 to control the mobile phone 1 and various programs and data for realizing a navigation function.

The RAM 90 is a readable / writable volatile storage device, and forms a work area for temporarily storing a system program executed by the host CPU 30, various processing programs, data being processed in various processing, processing results, and the like. .

2. Data Configuration FIG. 2 is a diagram illustrating an example of data stored in the ROM 23 of the baseband processing circuit unit 20. The ROM 23 is read by the CPU 21, and baseband processing (see FIG. 6).
Is stored as a baseband processing program 231. The baseband processing program 231 includes a positioning basic position error correction program 2311 executed as a positioning basic position error correction process (see FIG. 7) as a subroutine.

In the baseband processing, the CPU 21 sets the search range of the frequency and phase of the GPS satellite signal based on an error included in the positioning base position (hereinafter referred to as “positioning base position error”), and the search range In this process, the GPS satellite is acquired by searching for the frequency and the phase within the network. Then, the CPU 21 is referred to as captured satellite movement information (hereinafter referred to as “satellite movement information”).
) Is used to calculate the position and speed of the mobile phone 1.

In the present embodiment, the positioning calculation is performed using the positioning position previously determined (last) (hereinafter referred to as “previous positioning position”) as the positioning base position. As the positioning calculation, a known technique such as positioning calculation using a least square method or positioning calculation using a Kalman filter can be applied. The baseband process will be described later in detail using a flowchart.

In the positioning basic position error correction process, the CPU 21 calculates an “integer part” (hereinafter referred to as “first portion”) of the pseudo distance between the captured satellite and the mobile phone 1 calculated based on the positioning basic position and the satellite position of the captured satellite. "Integer part") and "integer part" (hereinafter referred to as "second integer part") of the pseudorange between the captured satellite and the mobile phone 1 calculated based on the Z count obtained from the captured satellite. ) Is a process for correcting the positioning base position error based on the difference from ().

Here, the Z count is information relating to the transmission time of the GPS satellite signal carried in the subframe of the navigation data, and corresponds to HOW (Hand Over Word). Further, as described above, a GPS satellite signal transmitted from a GPS satellite is a communication signal modulated by a PRN code which is a kind of spreading code different for each satellite.

The meaning of “integer part” will be described. Since the GPS satellite signal is repeatedly modulated with the PRN code, it is conceptually considered that the PRN code is continuously arranged between the GPS satellite and the mobile phone 1 as shown in FIG. be able to. However, the distance from the GPS satellite to the mobile phone 1 is not always an “integer multiple” of the length of the PRN code. In this case, the length obtained by adding the fractional part to the “integer multiple” of the length of the PRN code is the pseudo distance between the GPS satellite and the mobile phone 1. The integer of “integer multiple” is the “integer part” of the first integer part and the second integer part. The distance corresponding to the code length of the PRN code is “300 km”.
It is.

FIG. 3 is a diagram illustrating an example of data stored in the RAM 25 of the baseband processing circuit unit 20. In the RAM 25, satellite movement information data 251, positioning basic position data 252,
Assumed maximum speed data 253, previous positioning time data 254, positioning basic position error data 2
55, first integer part data 256, second integer part data 257, measurement data 2
58 is stored.

FIG. 5 is a diagram illustrating an example of a data configuration of the satellite movement information data 251. As illustrated in FIG. In the satellite movement information data 251, the satellite position and the satellite velocity vector are stored in association with each other as the satellite movement information 2513 for each of the captured satellites 2511 captured. The satellite position is represented, for example, as a three-dimensional coordinate value in the earth reference coordinate system, and the satellite velocity vector is represented, for example, as a three-dimensional vector in the earth reference coordinate system. The satellite movement information data 251 is updated by the CPU 21 in the baseband process.

The positioning basic position data 252 is data on the positioning basic position of the mobile phone 1 and is updated by the CPU 21 in the baseband processing.

The assumed maximum speed data 253 is data on the maximum speed assumed as the speed at which the mobile phone 1 moves (hereinafter referred to as “assumed maximum speed”), and is determined by the CPU 21 in the initial setting of baseband processing. A value (for example, “200 km / h”) is set and stored.

The previous positioning time data 254 is data about the time at which the positioning position is obtained by the previous positioning calculation (hereinafter referred to as “previous positioning time”), and is the CP in the baseband processing.
Updated by U21.

The positioning basic position error data 255 is data on the positioning basic position error, and is updated by the CPU 21 in the baseband processing. The positioning basic position error is calculated by multiplying the assumed maximum speed by the time difference between the current time measured by the clock unit 27 and the previous positioning time.

The first integer part data 256 is data about the first integer part of the pseudorange,
It is updated by the CPU 21 in the baseband process. Similarly, the second integer part data 257 is data about the second integer part of the pseudorange, and is updated by the CPU 21 in the baseband process.

The measurement data 258 is data about the position and speed of the mobile phone 1 obtained by the positioning calculation, and is updated by the CPU 21 in the baseband processing.

3. FIG. 6 shows a baseband processing program 2 stored in the ROM 23 by the CPU 21.
10 is a flowchart showing a flow of baseband processing executed in the mobile phone 1 by reading and executing 31.

The baseband processing is performed together with the reception of the GPS satellite signal by the RF receiving circuit unit 11 and the CP
This is a process for starting execution when U21 detects that a positioning start instruction is operated on the operation unit 40, and is a process performed in parallel with various processes such as execution of various applications. Note that the baseband processing may be started when the power-on operation of the mobile phone 1 is detected by linking the power-on / off of the mobile phone 1 and the activation / stop of GPS.

First, the CPU 21 performs initial setting (step A1). Specifically, when the positioning base position is not stored in the RAM 25, a predetermined position (for example, the position of a wireless base station that can be currently communicated) is set as the positioning base position, and is stored in the RAM 25 as the positioning base position data 252. . Further, when the assumed maximum speed is not stored in the RAM 25, a predetermined value (
For example, “200 km / h”) is set and stored in the RAM 25 as the assumed maximum speed data 253.

Further, when the previous positioning time is not stored in the RAM 25, the CPU 21 sets the current time measured by the clock unit 27 as the previous positioning time, and stores it in the RAM 25 as the previous positioning time data 254. Further, the CPU 21 sets the positioning base position error correction processing flag to OFF.

Next, the CPU 21 starts the positioning basic position error correction process by reading and executing the positioning basic position error correction program 2311 stored in the ROM 23 (step A3).

Thereafter, the CPU 21 sets the time difference between the current time measured by the clock unit 27 and the previous positioning time stored in the previous positioning time data 254 to the assumed maximum speed stored in the assumed maximum speed data 253 of the RAM 25. By multiplying, a positioning basic position error is calculated and stored in the RAM 25 as positioning basic position error data 255 (step A5).

After that, the CPU 21 determines the GP to be captured based on the latest almanac data and the like.
S satellite (hereinafter referred to as “capture target satellite”) is determined (step A7). More specifically, the positioning base position data 25 in the RAM 25 at the current time measured by the clock unit 27.
GPS satellites located in the sky at the positioning base position stored in 2 are determined from almanac and ephemeris data. Then, the CPU 21 performs loop A for each acquisition target satellite.
Is executed (steps A9 to A21).

In the loop A, the CPU 21 determines whether or not the acquisition target satellite has been successfully acquired in the past (step A11), and determines that the acquisition has not been successful (step A11; No).
First time search determination setting processing is performed (step A13). Specifically, for the frequency, a predetermined range centered on the IF frequency after down conversion corresponding to the carrier frequency (1.57542 “GHz”) of the GPS satellite signal is set as the search range. At this time, RAM
The smaller the positioning base position error stored in the 25 positioning base position error data 255,
Set the search range to narrow the search range. For the phase, the search range is set within the phase range of 1023 chips, which is the chip length of the PRN code.

If it is determined in step A11 that the capture target satellite has been successfully captured in the past (step A11; Yes), the CPU 21 performs a search range setting process (step A15). Specifically, for the frequency, a predetermined range centered on the frequency captured at the time of initial capture is set as the search range. At this time, the search range is set so that the smaller the positioning base position error stored in the positioning base position error data 255 of the RAM 25 is, the narrower the search range is. As for the phase, a predetermined range centered on the code phase captured at the time of initial capture is set as the search range.

After setting the search range in step A13 or A15, the CPU 21 performs satellite capture processing and attempts to capture the capture target satellite (step A17). Specifically, the correlation calculation in the phase direction for detecting the start position (code phase) of the PRN code within the search range set in step A13 or A15, and the correlation calculation in the frequency direction for detecting the frequency, To extract the frequency and code phase having the maximum correlation value.

Next, the CPU 21 calculates the satellite position and the satellite velocity vector of the capture target satellite based on the navigation data superimposed on the GPS satellite signal captured in step A17, and the satellite movement information data in the RAM 25 as the satellite movement information. 251 (step A19
). Then, the CPU 21 shifts the processing to the next capture target satellite.

After performing the process of loop A for all the capture target satellites (step A21), the CPU 2
1 performs a known positioning calculation, measures the current position and current speed of the mobile phone 1,
The measurement data 258 in the RAM 25 is stored (Step A23). The speed of the mobile phone 1 can be calculated based on the relative speed between the captured satellite and the mobile phone 1.

Next, the CPU 21 outputs the positioning position measured in step A23 to the host CPU 30 (step A25). Then, the CPU 21 updates the positioning base position data 252 in the RAM 25 using the current positioning position as the positioning base position (step A27). Further, the previous positioning time data 254 in the RAM 25 is updated with the current positioning time as the previous positioning time (step A29). Further, the CPU 21 sets a flag to OFF (step A31).

Thereafter, the CPU 21 determines whether or not to end positioning (step A33). If it is determined that the positioning has not ended yet (step A33; No), the CPU 21 returns to step A5. When it is determined that the positioning is to be ended (step A33; Yes), the baseband process is ended.

FIG. 7 is a flowchart showing a flow of positioning basic position error correction processing.
First, the CPU 21 determines whether or not the flag is set to OFF (step B1).
), If it is determined that it is set to ON (step B1; No), it waits as it is. If it is determined that the flag is set to OFF (step B1; Yes),
It is determined whether or not there is a captured satellite that can acquire the Z count (step B3).

If it is determined in step B3 that there is no captured satellite that has acquired the Z count (step B3; No), the CPU 21 returns to step B1. If it is determined that there is a captured satellite that can acquire the Z count (step B3; Yes), the satellite position of the captured satellite is calculated (step B5).

Next, the CPU 21 determines the pseudo distance between the captured satellite and the mobile phone 1 based on the positioning basic position stored in the positioning basic position data 252 of the RAM 25 and the satellite position of the captured satellite calculated in step B5. Is calculated as a first integer part and stored in the RAM 25 as first integer part data 256 (step B7).

Further, the CPU 21 determines that the captured satellite and the mobile phone 1 are based on the acquired Z count.
The “integer part” of the pseudo distance between them is calculated as the second integer part, and the second integer part data 25
7 is stored in the RAM 25 (step B9).

Next, the CPU 21 determines whether or not the first integer part and the second integer part match (step B11). If the CPU 21 determines that they match (step B11; Yes), the RAM 2
The positioning basic position error stored in the positioning basic position error data 255 of “5” is “300 km”.
It is determined whether or not this is the case (step B13).

In the present embodiment, description will be made on the assumption that the threshold value of the positioning basic position error is calculated as “300 km”, which is a distance corresponding to the code length of the PRN code, but a predetermined unit length (for example, “
100 km ") may be used as the threshold value for the positioning basic position error.

If it is determined that the positioning base position error is “300 km” or more (step B
13; Yes), the CPU 21 corrects the positioning base position error to “290 km” and corrects the RAM 2
5 positioning basic position error data 255 is updated (step B15), the positioning basic position error correction processing is terminated.

Although the first integer part and the second integer part match, the positioning base position error is “3”.
“00 km” or more means that the setting of the positioning base position error is considered to be incorrect, and therefore the positioning base position error is corrected to a value smaller than the threshold value. The correction value “290 km” is merely an example, and other correction values (for example, “295 km”) are used.
Of course, it may be good.

On the other hand, when it is determined in step B11 that the first integer part does not match the second integer part (step B11; No), the CPU 21 performs positioning stored in the positioning basic position error data 255 of the RAM 25. It is determined whether or not the base position error is “300 km” or more (step B19).

If it is determined that the positioning base position error is less than “300 km” (step B
19; No), the positioning basic position error is expressed as “(| first integer part−second integer part | +1) × 3
After correcting to “00 km” and updating the positioning basic position error data 255 of the RAM 25 (step B21), the positioning basic position error correction processing is terminated.

Although the first integer part does not match the second integer part, the positioning base position error is “
If it is less than “300 km”, the setting of the positioning basic position error is considered to be incorrect, and therefore the positioning basic position error is corrected to a value larger than the threshold value. still,
The correction value “(| first integer part−second integer part | +1) × 300 km” is merely an example, and other correction values (for example, “1000 km” uniformly) may be used. .

When it is determined in step B13 that the positioning base position error is less than “300 km” (step B13; No), or in step B19, the positioning base position error is “
If it is determined that it is equal to or greater than “300 km” (step B19; Yes), the CPU 21
The positioning basic position error correction process is terminated without correcting the positioning basic position error.

4). Effects According to the present embodiment, the first pseudo distance (first integer part) calculated by regarding the positioning base position as the position of the mobile phone 1, and the time between the transmission time and the reception time of the GPS satellite signal Based on the difference from the second pseudo distance (second integer part) calculated based on the difference, the position error with respect to the positioning base position is corrected. Then, a GPS satellite signal search range is set using the position error, and positioning is performed by receiving the GPS satellite signal based on the search range.

If the difference between the first pseudo distance and the second pseudo distance calculated by different calculation methods is small, the first pseudo distance in which the positioning base position is regarded as the position of the mobile phone 1 has a certain reliability (accuracy). Therefore, the position error can be corrected to a smaller value. On the other hand, if the difference between the first pseudo distance and the second pseudo distance is large, reliability (accuracy) is not recognized in the first pseudo distance in which the positioning base position is regarded as the position of the mobile phone 1. Therefore, the position error can be corrected to a larger value.

In the present embodiment, when a Z count is acquired from any one of a plurality of GPS satellites, a pseudo distance is calculated for the GPS satellite from which the Z count is acquired. Then, using the positioning basic position error corrected based on the pseudo-range difference for the GPS satellite, the frequency search range when receiving GPS satellite signals from GPS satellites other than the GPS satellite is varied. . Therefore, based on the difference between the first pseudo distance and the second pseudo distance calculated for one GPS satellite, it is possible to variably set the search range of signals of other GPS satellites.

5. Modified example 5-1. Electronic Device In the above-described embodiment, a mobile phone has been described as an example of an electronic device provided with a positioning device, but an electronic device to which the present invention can be applied is not limited thereto. For example, 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 Sy)
stem), GLONASS (GLObal NAvigation Satellite System), GALILEO, and other satellite positioning systems may be applied.

5-3. Differentiation of Processing The host CPU 30 may perform part or all of the processing performed by the CPU 21.
For example, the host CPU 30 performs positioning basic position error correction processing, and the CPU 21 performs satellite acquisition processing by varying the search range based on the processing result. Further, the host CPU 30 may perform a positioning calculation.

5-4. Satellite capture unit In the above-described embodiment, it has been described that the CPU 21 performs satellite capture processing to implement satellite capture in software, but the baseband processing circuit unit 20 is a circuit unit that captures satellites. The capturing unit may be provided independently and realized as hardware. In this case, according to the frequency and phase search range set by the CPU 21, the satellite capturing unit performs a correlation operation to capture the satellite.

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 baseband process circuit part. The figure which shows an example of the data stored in RAM of a baseband process circuit part. Explanatory drawing of a pseudo distance. The figure which shows an example of a data structure of satellite movement information data. The flowchart which shows the flow of a baseband process. The flowchart which shows the flow of a positioning basic position error correction process.

Explanation of symbols

1 mobile phone, 5 GPS antenna, 10 GPS receiver,
11 RF receiving circuit section, 20 baseband processing circuit section, 21 CPU,
23 ROM, 25 RAM, 27 clock section, 30 host CPU,
40 operation unit, 50 display unit, 60 mobile phone antenna,
70 wireless communication circuit for mobile phone, 80 ROM, 90 RAM

Claims (7)

A positioning device is a positioning method that performs positioning by receiving the positioning signal from a positioning satellite that transmits the positioning signal by periodically sending the transmission time,
Calculating a first pseudo-range that regards a given positioning base position as the position of the positioning device;
Calculating a second pseudo distance based on a time difference between the transmission time and the reception time at the time of reception;
Setting a position error for the given positioning base position;
Correcting the position error based on a difference between the first pseudorange and the second pseudorange;
Setting a signal search range when receiving the positioning signal using the position error;
Receiving the positioning signal based on the signal search range and performing positioning;
Positioning method including. Setting the position error includes setting the position error wider as the elapsed time from the last positioning is longer,
When the difference between the first pseudo distance and the second pseudo distance satisfies a predetermined approximate condition, the correction of the position error is preset as a position error when the approximate condition is satisfied. Including correcting the position error to a position error for pseudo distance approximation,
The positioning method according to claim 1. The correction of the position error means that the difference between the first pseudo distance and the second pseudo distance does not satisfy the predetermined approximation condition, and the position error is smaller than the pseudo distance approximation position error. A correction of the position error based on a difference between the first pseudorange and the second pseudorange.
The positioning method according to claim 2. The positioning signal is encoded with a pseudo-noise code,
Correcting the position error is performing the correction using the predetermined approximate condition as being within a distance corresponding to the code length of the pseudo-noise code.
The positioning method according to claim 2 or 3. Detecting that the transmission time from any one of the plurality of positioning satellites is received;
Calculating the first pseudorange and calculating the second pseudorange is to calculate a pseudorange related to the positioning satellite that has transmitted the received transmission time;
Setting the signal search range includes changing a signal search range of a frequency when receiving a positioning signal from a positioning satellite other than the positioning satellite that has transmitted the received transmission time.
The positioning method as described in any one of Claims 1-4. The program for making the computer incorporated in the positioning apparatus perform the positioning method as described in any one of Claims 1-5. A positioning device that performs positioning by receiving the positioning signal from a positioning satellite that transmits the positioning signal periodically with a transmission time,
A detection unit for detecting that the transmission time has been received;
A first calculation unit that calculates a first pseudo-range that regards a given positioning base position as the position of the positioning device;
Second based on the time difference between the transmission time detected by the detection unit and the reception time at the time of reception.
A second calculation unit for calculating the pseudorange of
A position error setting unit for setting a position error with respect to the given positioning base position;
A position error correction unit that corrects the position error based on a difference between the first pseudo distance and the second pseudo distance;
A signal search range setting unit for setting a signal search range when receiving the positioning signal using the position error;
A positioning unit that performs positioning by receiving the positioning signal based on the signal search range;
Positioning device equipped with.

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