JPH08292247A - Positioning system - Google Patents

Abstract

PURPOSE: To obtain a highly accurate result of positioning in a positioning method using a D.GPS (differential global positioning system) without increasing errors in a differential correction value even when FM multiplex DARC data are missed to be updated, e.g. because of a place where FM waves are impossible to detect. CONSTITUTION: As DARC data received after multiplexed with FM signals are updated, a pseudo distance correction value PRC and a distance change rate correction value RRC for a DGPS are extracted via a differential data extraction part 35, whereby a change with time of the distance change rate correction value RRC is calculated by a differential correction value operation part 39. If a satellite detection time of a DGPS receiver 43 extracted by a time data extraction part 40 is updated, a pseudo distance correction value PRC(t-old) immediately before the DARC data are updated is corrected based on a distance change rate correction value RRC(t) corresponding to a present time (t) with the calculated change with time of the correction value RRC taken into consideration, thereby to obtain a pseudo distance correction value PRC(t) of the present time, which is sent to the DGPS receiver 43.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention determines the position of a moving body such as an automobile, a ship or an aircraft based on a signal received directly from a plurality of satellites and a correction signal received from a fixed reference station. The present invention relates to a positioning method using a differential GPS (Global Positioning System) that measures and outputs with high accuracy.

[0002]

2. Description of the Related Art Conventionally, in a moving body such as an automobile, a ship, and an aircraft, a GPS has been put into practical use which measures and outputs the position of the moving body based on signals directly received from a plurality of satellites.

That is, the GPS calculates pseudo distances from the respective satellites based on signals received from a plurality of satellites, and the moving position (latitude, longitude) of the moving body on the earth.
Thus, for example, in a car navigation device using GPS, the moving position of the vehicle is displayed on a road map.

However, in the GPS, the signal received from each satellite may include, for example, an ionospheric delay error or a troposphere delay error that changes the signal arrival time.
Since various error factors are included, errors will inevitably occur in the moving position measured based on the satellite signal including these error factors.

Therefore, in a fixed reference station whose exact position on the earth is known beforehand, the position of the reference station is measured by the GPS, and a correction signal is created according to the difference between the measured position and the position of the previously mentioned reference station. , For example, by transmitting as FM multiplex broadcasting, the mobile unit receives a plurality of satellite signals and measures their moving positions, and the measured moving positions are multiplexed and received as the FM broadcasting. A differential-type GPS, that is, D-GPS, has been considered in which a moving position of a moving body is obtained with extremely high accuracy by performing correction according to a correction signal.

FIG. 4 is a diagram showing the overall configuration of a differential GPS using FM multiplex broadcasting. First, the D / GPS fixed reference station 11 whose accurate position on the earth is known in advance receives signals from a plurality of GPS satellites 12a, 12b, ... And measures the reference station position based on the satellite signals. Correction value data is created according to the difference between the reference station position measured by the GPS satellite and a known accurate reference station position.

The correction value data created by the D / GPS fixed reference station 11 is the FM multiplex DARC data control unit 1.
3, DARC (registered trademark) (Data Radio Chann
el) Formatting is performed according to the transmission format.

FIG. 5 is a diagram showing the structure of a DARC transmission frame multiplexed in FM broadcasting. This DARC transmission frame has 272 blocks of packets transmitted at 5 (SEC) per frame, of which two data packets are assigned as transmission packets.

FIG. 6 is a view showing the contents of D / GPS data assigned to the two packets of the DARC transmission frame. As the D / GPS data assigned to the two packets of the DARC transmission frame, the data identification number (data ID) and the correction time data creation time (Time
of GPS satellites 1
Correction data set corresponding to each satellite obtained based on the received signals from 2a, 12b, ... And communication data (Communic) indicating normality / abnormality of each satellite
ation Data) is given.

FIG. 7 is a diagram showing the contents of the correction data set of each satellite given as the D / GPS data. That is, for example, as the correction data set corresponding to each of the satellites 1 to 8, the pseudo range correction value (PR
C) Scale Factor (SF), user differential distance error index (User Different
ial Range Error: UDER, satellite identification number (Satell)
ite ID: St. ID), correction value of pseudo distance (Pseudorang
e Correction: PRC), the pseudo distance correction value (PRC)
Correction value of the distance change rate, which is the change rate per second of
Rate Correction: RRC) and a data issue number (Issue Of Data: IODE) indicating orbital data of the satellite are given.

In this way, in the FM multiplex DARC data control unit 13, the correction data corresponding to each of the eight GPS satellites 12a, 12b, ... In the FM voice (music) signal is multiplexed and modulated by frequency division, and is transmitted from the transmitter 15 of the FM station via the transmitting antenna 16 to the FM multiplex DAR.
It is transmitted as a C system broadcast signal.

Here, the correction data assigned to the DARC transmission frame is updated and transmitted every 5 seconds which is a transmission time per frame. On the other hand, a D / GPS receiver 18 mounted on a moving body 17 such as an automobile receives signals from the plurality of GPS satellites 12a, 12b, ... And calculates a pseudo distance from each satellite 12a, 12b ,. At the same time, the moving position of the moving body 17 is measured based on the calculated pseudo distances to the respective satellites 12a, 12b, ....

Further, the FM multiplex receiver 19 mounted on the mobile unit 17 receives the broadcast signal of the FM multiplex DARC system, and DA multiplexed with the broadcast signal.
The correction value data in the RC format is extracted and converted into a data format standardized by RTCM (Marine Radio Technical Committee), and the D / GPS receiver 1 is used.
Supply to 8.

As a result, the D / GPS receiver 18
Then, based on the correction value data obtained in the RTCM standardized format, the moving position of the moving body 17 measured by the D / GPS receiver 18 is corrected, and highly accurate position measurement can be achieved.

FIG. 8 shows a D / GPS receiver 18 and an FM multiplex receiver 19 mounted on a conventional D / GPS mobile unit.
FIG. 3 is a block diagram showing the configuration of FIG. In the moving body 17,
FM multiplex DARC transmitted from the transmitting antenna 16
When a broadcasting signal of the system is received by the FM tuner 22 via the FM antenna 21, the FM multiplex signal received by the FM tuner 22 is FM-multiplexed by the FM multiplex decoder 23.
Separated into voice (music) signals and DARC format data, the DARC format data is DAR
It is given to the C → RTCM converter 24.

This DARC → RTCM converter 24 has 5
The pseudo distance correction value PRC, the distance change rate correction value RRC extracted from the DARC format data updated and given every second, and the correction value creation time (t0) and D / GP.
GP extracted from the GPS tuner 26 of the S receiver 18
Difference (t) from the reception signal time (t) of the S satellites 12a, 12b, ...
-t0) according to the following equation (1), the pseudo-range correction value PRC (t) that matches the current satellite reception time (t) at the D / GPS receiver 18 is calculated and calculated. The distance correction value PRC (t) and the distance change rate correction value RRC per second are converted into RTCM format data and sent to the GPS tuner 26.

PRC (t) = PRC (t0) + RRC × (t−t0) Equation (1) Then, in the GPS tuner 26, the GPS satellites 12a,
Pseudo distance P calculated based on the received signals from 12b, ...
Rm (t) is the pseudo distance correction value PRC and the distance change rate correction value RR given from the DARC → RTCM converter 24.
Based on C and C, the pseudo distance PR after the correction is obtained by performing the correction according to the following equation (2).

PR = PRm (t) + PRC + RRC (t−t0) Equation (2) However, the time (t0) in this Equation (2) is the DARC.
→ From the RTCM converter 24 to the GPS tuner 26,
The time when the pseudo distance correction value PRC and the distance change rate correction value RRC converted into the RTCM format data are given is shown.

Therefore, for example, when the pseudo distance correction value PRC and the distance change rate correction value RRC converted into the RTCM format data are given to the GPS tuner 26, the time (t0) = (t) is satisfied. , The distance change rate correction value RRC indicating the rate of change of the pseudo distance correction value PRC per second in the equation (2) is substantially “0”, and the corrected pseudo distance PR at that time is only PRm (t) + PRC. Required by.

Then, when the current time (t) is 1 second → 2 seconds → ... from the time (t0) when the pseudo distance correction value PRC and the distance change rate correction value RRC are given to the GPS tuner 26, Correspondingly, (t −t0) in the above equation (2)
Since the time difference of changes directly as “1” → “2” → ..., the corrected pseudo distance PR is PRm (t)
+ PRC + RRC × “1” → PRm (t) + PRC +
RRC × “2” → ...

Thus, the plurality of GPS satellites 12a, 1a
2b, ... Pseudo distances PRa, PRb, after correction
Is obtained, and the position of the moving body is measured based on this. FIG. 9 shows the conventional D / GPS DARC → RTCM.
6 is a flowchart showing a differential correction value generation process in the converter 24.

FIG. 10 is a diagram showing a change state of the differential correction value calculation result with the passage of time in the conventional D / GPS. That is, for example, at time t0, when the DARC data of the FM multiplex broadcast received by the FM multiplex receiver 19 is updated, DARC → RTC
In the M converter 24, the current satellite reception time is read from the D / GPS receiver 18 (step A1 → A2).

Then, the difference between the satellite reception time read from the D / GPS receiver 18 and the correction value creation time of the pseudo distance correction value PRC and the distance change rate correction value RRC included in the updated DARC data is calculated. Based on the above, the arithmetic processing for PRC and RRC according to the above equation (1) is executed, and the pseudo distance correction value PRC (0) matching the current satellite reception time in the D / GPS receiver 18 is calculated (step A3). .

Thus, the DARC → RTCM converter 24
The pseudo distance correction value PRC (0) obtained in step S4 is converted into RTCM format data together with the distance change rate correction value RRC (0), and is sent to the D / GPS receiver 18 (step A4).

That is, when the DARC data received by the FM multiplex receiver 19 and demodulated and separated is updated, the pseudo range correction value RP matching the satellite reception time (0) at that time t0.
C (0) is obtained, converted into RTCM data together with the distance change rate correction value RRC (0) and sent to the GPS tuner 26. According to the update of the DARC data, the satellite reception time (0 ), The pseudo distance correction value RPC (0) and the distance change rate correction value RRC (0) are given to the GPS tuner 26, the pseudo distance correction value RP
C (0), distance change rate correction value RRC (0) and satellite reception time
Since there is no time difference with (0), GPS tuner 2
Pseudo distance correction value PRC (t0) at time t0 used in 6
Is calculated as PRC (0) + (RRC (0) × 0),
Pseudo-range PR measured based on the current satellite reception signal
Differential correction process for m (t0) “PR = P
Rm (t0) + PRC (t0) "is performed.

Then, at time t1 when, for example, one second has passed from time t0, DARC → RTC at time t0.
A time difference of 1 second occurs between the pseudo distance correction value RPC (0) and the distance change rate correction value RRC (0) given from the M converter 24 to the GPS tuner 26 and the current satellite reception time (1). Therefore, the pseudo distance correction value PRC (t1) at the time t1 used in the GPS tuner 26 is PRC (0) + (RRC (0) ×
The differential correction process “PR = PRm (t1) + PRC (t1)” for the pseudo distance PRm (t1) calculated as 1) and measured based on the satellite reception signal at the present time is performed.

Further, at time t2 when, for example, 2 seconds have passed from time t0, DARC → RTC at time t0.
A time difference of 2 seconds occurs between the pseudo range correction value RPC (0) and the distance change rate correction value RRC (0) given from the M converter 24 to the GPS tuner 26 and the current satellite reception time (2). Therefore, the pseudo distance correction value PRC (t2) at the time t2 used in the GPS tuner 26 is PRC (0) + (RRC (0) ×
2), the differential correction process “PR = PRm (t2) + PRC (t2)” for the pseudo distance PRm (t2) calculated based on the satellite reception signal at the present time is performed.

Thereafter, when the DARC data received by the FM multiplex receiver 19 and demodulated and separated is updated at time t5, which is 5 seconds after the time t0, the satellite reception time (5) at the time t5 is adjusted. Pseudo distance correction value RPC (5)
Is obtained by the DARC → RTCM converter 24, converted into RTCM data together with the distance change rate correction value RRC (5) and sent to the GPS tuner 26.
According to the update of C data, satellite reception time at that time t5
When the pseudo distance correction value RPC (5) and the distance change rate correction value RRC (5) according to (5) are given to the GPS tuner 26, the pseudo distance correction value RPC (5) and the distance change rate correction value RRC are given. Since there is no time difference between (5) and the satellite reception time (5), the pseudo range correction value PRC (t5) at time t5 used in the GPS tuner 26 is PRC (5) + (RRC
(5) × 0), and the differential correction process “PR = PRm (t5) + PRC (t5)” for the pseudo distance PRm (t5) measured based on the satellite reception signal at the present time is performed.

That is, in the conventional D / GPS, 5
When the DARC data is updated every second (t0, t5, t10, t
In (15), the differential correction processing is performed by the pseudo distance correction value RPC (0,5,10,15) which is given from the DARC → RTCM converter 24 to the GPS tuner 26 and matches the satellite reception time at each time. , (D1, ~, t4) (t6, ~, t9) (t11, ~, t14), the pseudo distance correction value RPC (0, 5, 1
The differential correction processing is performed with a value obtained by adding the elapsed time of each corresponding distance change rate correction value RRC (0,5,10) to (0).

[0030]

However, in the above-mentioned conventional D / GPS, the DARC → RTCM converter 24 to the GPS tuner 2 are accompanied by the update of the DARC data.
6, the temporal change rate R of the pseudo distance correction value PRC
When RC changes over time, DARC
As the time elapsed after updating the data progresses, the error between the pseudo distance correction value PRC obtained by adding the time elapsed time of the RRC in the GPS tuner 26 and the actual pseudo distance correction value PRC (t) becomes large. Therefore, there is a problem that the positioning accuracy is lowered by the differential correction.

FIG. 11 is a diagram showing a change state of the differential correction value calculation result with the lapse of time when the update of the DARC data at time t10 is missing in the conventional D.GPS.

That is, FM multiplex D updated every 5 seconds
In the state where the ARC data is normally received by the FM multiplex receiver 19 mounted on the moving body 17 every time, as shown in FIG. 10, the distance change rate correction value RRC itself is accompanied by a temporal change. Actual pseudo distance correction value PRC
The error from (t) does not become too large, and the positioning accuracy due to the differential correction does not decrease significantly. However, for example, the moving body 17 is in a tunnel or a valley of a building.
As shown in FIG. 11, when passing through an unreceivable place, if the update of the DARC data at time t10 is missing, a new DARC is added for 10 seconds from time t5 to t15.
Since the correction value data corresponding to the data will not be updated, the pseudo distance correction value PRC obtained by adding the elapsed time of RRC (5) to PRC (5) and the actual pseudo distance correction value PRC during that time. There is a problem that the error from (t) becomes large and the positioning accuracy due to the differential correction is significantly reduced.

The present invention has been made in view of the above-mentioned problems, and, for example, accompanying the passage of a place where FM reception is impossible,
An object of the present invention is to provide a positioning method capable of obtaining a highly accurate positioning result without increasing the error of the differential correction value even when the update of the DARC data received as FM multiplex broadcasting is lost. .

[0034]

That is, in the positioning system according to claim 1 of the present invention, positioning information measured based on signals received from a plurality of satellites is updated to an FM signal at regular intervals. Is a positioning method for performing correction on the basis of first correction data extracted from multiplexed data that has been multiplexed and second correction data that indicates a rate of change of the first correction data per unit time. A second correction data change calculation means for calculating a time change of the second correction data extracted from the second correction data and the second correction data change calculation means when the satellite reception time for measuring the positioning information is updated. Correction data calculating means for calculating the correction data of the positioning information by correcting the first correction data based on the second correction data in consideration of the temporal change of the calculated second correction data. It is characterized in.

Further, in the positioning system according to claim 2 of the present invention, the positioning information measured based on the signals received from a plurality of satellites is multiplexed into the FM signal by being updated at regular intervals. A positioning method for performing correction based on first correction data extracted from data and second correction data indicating a rate of change of the first correction data per unit time,
When the multiplexed data multiplexed in the FM signal is updated, first and second correction data extracted from the updated multiplexed data, and the creation time of the correction data and the current positioning information measurement Correction data calculation at the time of multiplex data update for correcting the first correction data with the second correction data to calculate the correction data of the positioning information corresponding to the current measurement time based on the time difference from the satellite reception time. Means, a correction data storage means for storing the positioning information correction data calculated by the correction data calculation means at the time of updating the multiplex data together with the second correction data, and the multiplex data multiplexed on the FM signal are updated. At this time, the amount of change between the second correction data extracted from the updated multiplex data and the second correction data stored in the correction data storage means at the time of the previous multiplex data update, And a second correction data change calculation means for calculating the temporal change of the second correction data based on the elapsed time from the time of the previous multiplex data update to the time of the current multiplex data update, and the second correction data change calculation A second storing the temporal change of the second correction data calculated by the means;
When the correction data change storage means and the multiplex data multiplexed in the FM signal are not updated and the satellite reception time for measuring the positioning information is updated, the correction data corresponding to the update of the multiplex data The positioning information correction data at that time stored in the storage means and the second correction data stored in the correction data storage means to the second correction data stored in the second correction data change storage means with time. Correction data corresponding to the current measurement time based on the second correction data corresponding to the current time and the elapsed time from the time of updating the multiplex data to the satellite reception time for measuring the current positioning information It is characterized in that it comprises a correction data calculation means for calculating the data when the multiplex data has not been updated.

[0036]

That is, in the positioning method according to claim 1 of the present invention, the distance change rate correction value R extracted from the DARC data is calculated.
When the time change of RC is calculated and the GPS satellite reception time is updated, the calculated distance change rate correction value RR
Based on the distance change rate correction value RRC (t) corresponding to the current time (t) in consideration of the temporal change of C, the pseudo distance correction value PRC (t-old) at the time of the last DARC data update is corrected to correspond to the current time. The pseudo distance correction value PRC (t) is calculated.

Further, in the positioning system according to the second aspect of the present invention, when the DARC data multiplexed in the FM signal is updated, the pseudo distance correction value PRC and the pseudo distance correction value PRC extracted from the updated DARC data and Distance change rate correction value RR
C and the pseudo distance correction value PRC (t0) based on the time difference "(t)-(t0)" between the creation time (t0) of the correction values PRC and RRC and the current GPS satellite reception time (t). Is corrected by the distance change rate correction value RRC "(t)-(t0)" to calculate and store the pseudo distance correction value PRC (t) corresponding to the current time, and the distance change rate at the time of the last DARC data update. Correction value R
The amount of change between RC (t-1) and the distance change rate correction value RRC (t) at the time of updating the DARC data this time, and its elapsed time "(t)-
(t-1) ", the temporal change of the distance change rate correction value RRC is calculated and stored, and the DA signal multiplexed in the FM signal is stored.
When the RC data is not updated and the GPS satellite reception time is updated, the pseudo distance correction value PRC (t-old) at that time calculated and stored at the time of the immediately previous DARC data update, and its distance change rate correction value RRC (t-old) to DAR immediately before
Distance change rate correction value RR calculated and stored when C data is updated
The distance change rate correction value RRC (t) corresponding to the current time in consideration of the temporal change of C, and the elapsed time "(t)-from the time immediately before the update of the DARC data to the current GPS satellite reception time"
Based on (t-old) ", the pseudo distance correction value PRC (t) corresponding to the current time is calculated.

[0038]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of electronic circuits of an FM multiplex receiver and a D / GPS receiver mounted on a moving body in a differential GPS implementing the positioning system of the present invention.

The FM multiplex DARC system broadcast signal transmitted from the transmitting antenna 16 (see FIG. 4) and updated every 5 seconds is transmitted via the FM antenna 31 attached to the mobile unit to the FM tuner of the FM multiplex receiver. Received by 32,
It is supplied to the FM multiplex decoder 33.

This FM multiplex decoder 33 is an FM multiplex DARC that is received and supplied by the FM tuner 32.
The system broadcast signal is demodulated and separated into the FM voice (music) signal and the data of the DARC system format.
The DARC format data demodulated and separated by the M multiplex decoder 33 is output to the differential data extraction unit 35 of the DARC → RTCM converter 34.

This differential data extraction unit 35
Is the D. GPS assigned to two data packets from the DARC format data (see FIG. 5) demodulated and separated by the FM multiplex decoder 33 and output.
Data (see FIG. 6) for extraction, and the D / GP extracted by the differential data extraction unit 35.
The S data is output to the PRC extraction unit 36 and the RRC extraction unit 37.

The PRC extractor 36 receives the D / GPS data extracted by the differential data extractor 35 at a fixed reference station (see FIG. 4).
For example, the pseudo-range correction value PRC corresponding to each of the eight GPS satellites is extracted.
Pseudorange correction value PRC for each satellite extracted by
Is output to the differential correction value calculation unit 39.

The RRC extraction unit 37 receives the D / GPS data extracted by the differential data extraction unit 35 at a fixed reference station (see FIG. 4).
A range change rate correction value RRC (change rate per second of the pseudo range correction value PRC) corresponding to each of the eight GPS satellites is extracted, and the pseudo of each satellite extracted by the RRC extractor 37 is extracted. The distance change rate correction value RRC corresponding to the distance correction value PRC is output to the differential correction value calculation unit 39.

The signals from the eight GPS satellites, which are received by the GPS sensor 44 of the D / GPS receiver 43 via the GPS antenna 42 attached to the moving body, are supplied to the positioning CPU 45.

This positioning CPU 45, based on the received signal from each satellite, pseudo range PRm with each satellite.
Is calculated for each fixed time (for example, 1 second), and the calculated pseudo range PRm with each satellite is calculated by the differential data CPU 46. The pseudo range correction value PRC and the range change rate correction corresponding to each satellite are given. This positioning CPU 4 corrects according to the value RRC, and measures the moving position (latitude, longitude, altitude) of the moving body on the earth based on the corrected pseudo distance PR with each satellite.
The moving position of the moving body measured in 5 is displayed on the monitor 47.
Is output and displayed.

In the positioning CPU 45, the time data shown in the position measurement satellite signal received and supplied from the GPS sensor 44 is used as the satellite reception time associated with the position measurement, that is, DARC → RTCM of the FM multiplex receiver.
The differential correction value calculation unit 3 outputs and extracts the time data extraction unit 40 provided in the converter 34.
9 is output.

The differential correction value calculation unit 39
D / GPS extracted by the time data extraction unit 40
The satellite reception time at the receiver 43 is updated and D
When the D / GPS data extracted by the differential data extraction unit 35 is updated due to the update of the ARC data, the correction value creation time (t0) and the GPS satellite reception time included in the D / GPS data are updated. Time difference from (t) (tt
0), the pseudo distance correction value PRC (t0) and the distance change rate correction value RRC (t0) extracted by the PRC extraction unit 36 and the RRC extraction unit 37, based on the current satellite reception time of the D / GPS receiver 43 ( The differential correction values PRC (t) and RRC (t) corresponding to t) are calculated and generated.
The differential correction values PRC (t) and RRC (t) corresponding to the current GPS satellite reception time (t) are stored in the correction value memory 38.

At the same time, the differential correction value calculation unit 39 uses the distance change rate correction value RRC (t-1) stored in the correction value memory 38 along with the previous update of the DARC data and the current DARC data. Correction value RRC stored in the correction value memory 38 in accordance with the update of
Change amount from (t) "RRC (t) -RRC (t-1)" and the elapsed time from the last DARC data update (t-1) to the current DARC data update (t) "(t )-(T-1) ", the rate of change in the distance change rate correction value RRC itself per unit time ΔRRC" = {RRC (t) -RRC (t-1)} /
{(T)-(t-1)} "is calculated by this DAR.
C Distance change rate correction value R per unit time immediately before data update
The rate of change ΔRRC of RC itself is stored in the correction value memory 38.

In this case, the differential correction values PRC (t) and RRC (t) matching the current satellite reception time (t) stored in the correction value memory 38 are formatted into RTCM format data via the data formatter 41. And is output to the differential data CPU 46 of the D / GPS receiver 43.

The differential correction value calculation unit 39 does not update the DARC data even when the satellite reception time of the D / GPS receiver 43 extracted by the time data extraction unit 40 is updated. D / GPS extracted by the differential data extraction unit 35
If the data for updating is not updated, the G at the time stored in the correction value memory 38 at the time of updating the DARC data.
Differential correction values PRC (t-old) and RRC (t-old) according to PS satellite reception time (t-old) and distance change rate correction value RRC per unit time Change rate ΔRR of itself
Based on C and the elapsed time "(t)-(t-old)" from the time when the DARC data is updated (t-old) to the current satellite reception time (t), according to the following equation (3), the current GPS The pseudo range correction value PRC (t) corresponding to the satellite reception time (t) is calculated and calculated. In this case, the pseudo range correction value PRC (corresponding to the current time calculated by the differential correction value calculation unit 39 is calculated. t) is the RTC via the data formatter 41
The differential data C of the D / GPS receiver 43 is formatted into M format data.
It is output to the PU 46.

PRC (t) = PRC (t-old) + [RRC (t-old) + ΔRRC × {(t) − (t-old)}] × {(t) − (t-old)} Equation (3) That is, the differential correction value calculation unit 39 uses the DA
At the time of updating the D / GPS data accompanying the update of the RC data, according to the difference between the creation time (t0) of the updated correction value data PRC and RRC and the current GPS satellite reception time (t), The pseudo distance correction value PRC (t) corresponding to the current time is calculated and generated according to the equation (1), and the distance change rate correction value R
It is converted into RTCM data together with RC (t) and output to the D / GPS receiver 43.

When updating the GPS satellite reception time other than when updating the D.GPS data, the D.GPS
For the pseudo distance correction value PRC (t-old) calculated and generated at the time of updating the use data, the distance change rate correction value RRC
(t-old) is the time elapsed until the current time (t) of the change rate ΔRRC of the distance change rate correction value RRC per unit time
C × {(t) − (t-old)} ”is added to the distance change rate correction value RRC (t) over time,“ RRC (t) × {(t) − (to
ld)} ”is added, and the pseudo distance correction value PR corresponding to the current time is added.
C (t) is arithmetically generated according to the above equation (3), and RTCM
The data is converted and output to the D / GPS receiver 43.

As a result, the D / GPS receiver 43
In the positioning CPU 45, the pseudo range PRm with each satellite calculated based on the received signal from each satellite is always accurately and differentially calculated in consideration of the temporal change of the distance change rate correction value RRC itself. And the FM / DARC data cannot be received.
Even if the update of the PS data is lost, the pseudo distance correction value PRC (t) without error is obtained, and the highly accurate movement position measurement processing is performed.

FIG. 2 shows the D of the differential GPS.
7 is a flowchart showing a differential correction value generation process performed by a differential correction value calculation unit 39 in the ARC → RTCM converter 34.

FIG. 3 is a diagram showing the change state of the correction value calculation result with the passage of time by the differential correction value generation processing of the differential GPS in association with the case where the update of the DARC data at time t10 is missing. .

That is, for example, at time t0, DG
Based on the GPS satellite reception time extracted from the PS receiver 43 via the time data extraction unit 40 of the DARC → RTCM converter 34, it is determined that the GPS satellite reception time is updated at 1 second intervals, and the FM multiplex decoder 33 is also provided. When it is determined that the DARC data demodulated and separated in 5 seconds is updated, the correction value creation time included in the D / GPS data extracted by the differential data extraction unit 35 and the GPS satellite reception time Time difference and PRC extraction unit 3
6, based on the pseudo distance correction value PRC and the distance change rate correction value RRC extracted by the RRC extraction unit 37, the pseudo distance correction value PRC (0) and the distance change rate correction value RRC (matched to the current satellite reception time t0 0) is calculated and stored in the correction value memory 38 (steps S1 → S2 → S3).

At the same time, the correction value memory 38 is updated in accordance with the previous update of the DARC data at time t-5.
Change amount correction value RRC (-5) stored in the correction value memory 38 and the distance change rate correction value RRC (0) stored in the correction value memory 38 due to the update of the DARC data at this time t0. Distance change per unit time based on "RRC (0) -RRC (-5)" and the elapsed time (5) from the last DARC data update (-5) to the current DARC data update (0). Change rate ΔRC of the rate correction value RRC itself “= {RRC
(0) -RRC (-5)} / 5 "is calculated and stored in the correction value memory 38 (step S4).

Then, in step S3, the differential correction values PRC (0) and RRC (0) matched with the current satellite reception time t0 stored in the correction value memory 38.
Is formatted into the RTCM format data via the data formatter 41 and sent to the differential data CPU 46 of the D / GPS receiver 43 (step S5).

In this case, the pseudo distance correction value RPC (0) and the distance change rate correction value calculated according to the update of the DARC data at the time t0 and transmitted to the D / GPS receiver 43 are adjusted to the satellite reception time t0. Since there is no time difference between the RRC (0) and the satellite reception time t0, D ・ GPS
Pseudo distance correction value PR at time t0 given to the receiver 43
C (t0) becomes the pseudo distance correction value PRC (0) itself when the distance change rate correction value RRC (0) becomes substantially “0”,
Pseudo-range PR measured based on the current satellite reception signal
Differential correction process for m (t0) “PR = P
Rm (t0) + PRC (t0) "is performed.

Then, at time t1 when, for example, one second has passed from the time t0, the D / GPS receiver 43 outputs DA
Based on the GPS satellite reception time extracted via the time data extraction unit 40 of the RC → RTCM converter 34, the GPS
It is determined that the satellite reception time is updated every 1 second, and F
When it is determined that the DARC data demodulated and separated by the M multiplex decoder 33 is not updated, the DARC at the time t0 is determined.
Changes in the differential correction values PRC (0), RRC (0) and the distance change rate correction value RRC itself, which are stored in the correction value memory 38 at the time of updating the data, according to the GPS satellite reception time t0 at that time Rate ΔRRC “=
{RRC (0) -RRC (-5)} / 5 ", and the DARC
The pseudo distance correction value PRC (t1) corresponding to the current GPS satellite reception time t1 is calculated and calculated based on the elapsed time “1” from the data update time t0 to the current satellite reception time t1, and the RTC
The D / GPS receiver 4 as M format data
It is sent to the differential data CPU 46 of No. 3 (steps S1 → S2 → S6, S5).

In this case, since the time difference between the time when the DARC data is updated at the time t0 and the current satellite reception time t1 is 1 second, the pseudo distance correction value PRC (t1) given to the D / GPS receiver 43 at the time t1. Is calculated according to the following equation (4) corresponding to the above equation (3), and the differential correction process “PR = PRm (t1) + PRC (t1) for the pseudo range PRm (t1) measured based on the satellite reception signal at the present time is calculated. ) ”Is performed.

PRC (t1) = PRC (0) + [RRC (0) + ΔRRC × 1] × 1 (4) where ΔRRC = {RRC (0) −RRC (-5)} / 5 Further, At time t2 when, for example, 2 seconds have passed from time t0, D / GPS receiver 43 outputs DARC → RTC.
Based on the GPS satellite reception time extracted through the time data extraction unit 40 of the M converter 34, it is determined whether the GPS satellite reception time is updated at 1 second intervals, and the FM multiplex decoder 33 demodulates and separates. If it is determined that the DARC data has not been updated, the same time as the processing at time t1
The units of the differential correction values PRC (0), RRC (0) and the distance change rate correction value RRC itself which are stored in the correction value memory 38 at the time of t0 and which are stored in the correction value memory 38 in accordance with the GPS satellite reception time t0 at that time. Rate of change ΔRRC "= {RRC (0) -RRC (-5)} / 5", and the satellite reception time t2 from the time t0 when the DARC data is updated.
The pseudo distance correction value PRC (t2) corresponding to the current GPS satellite reception time t2 is calculated and calculated based on the elapsed time "2" until the D / GP.
Differential data CPU 46 of S receiver 43
(Steps S1 → S2 → S6, S5).

In this case, since the time difference between the time when the DARC data is updated at the time t0 and the current satellite reception time t2 is 2 seconds, the pseudo distance correction value PRC (t2) given to the D / GPS receiver 43 at the time t2. Is calculated according to the following equation (5) corresponding to the above equation (3), and the differential correction processing “PR = PRm (t2) + PRC (t2) for the pseudo distance PRm (t2) measured based on the satellite reception signal at the present time is calculated. ) ”Is performed.

PRC (t2) = PRC (0) + [RRC (0) + ΔRRC × 2] × 2 Equation (5) where ΔRRC = {RRC (0) -RRC (-5)} / 5 At time t5 when 5 seconds have elapsed from time t0, G extracted from the D / GPS receiver 43 via the time data extraction unit 40 of the DARC → RTCM converter 34.
1 of the GPS satellite reception time based on the PS satellite reception time
When the update of the second interval is determined, the FM multiplex decoder 3
When it is determined that the DARC data demodulated and separated in 3 is updated at 5-second intervals, the differential data extraction unit 35
And the time difference between the correction value creation time included in the D / GPS data extracted in step 1 and the GPS satellite reception time, and PR
Based on the pseudo distance correction value PRC and the distance change rate correction value RRC extracted by the C extraction unit 36 and the RRC extraction unit 37,
Pseudo range correction value PRC according to the current satellite reception time t5
(5), the distance change rate correction value RRC (5) is calculated and stored, and stored in the correction value memory 38 (steps S1 → S2 → S).
3).

Along with this, the distance change rate correction value RRC (0) stored in the correction value memory 38 in accordance with the previous update of the DARC data at time t0 and the update of the DARC data at this time t5. Correction value memory 3
The change amount “RRC (5) −RRC (0)” with the distance change rate correction value RRC (5) stored in 8 and the time (5) when the previous DARC data was updated (0) Based on the elapsed time (5), the change rate ΔRC of the distance change rate correction value RRC itself per unit time “= {RRC (5)
-RRC (0)} / 5 "is calculated and calculated, and the correction value memory 3
8 is stored (step S4).

Then, in step S3, the differential correction values PRC (5) and RRC (5) matched with the current satellite reception time t5 stored in the correction value memory 38.
Is formatted into the RTCM format data via the data formatter 41 and sent to the differential data CPU 46 of the D / GPS receiver 43 (step S5).

In this case, the pseudo distance correction value RPC (5) and the distance change rate correction value which are calculated according to the update of the DARC data at the time t5 and are transmitted to the D / GPS receiver 43 according to the satellite reception time t5. Since there is no time difference between the RRC (5) and the satellite reception time t5, D ・ GPS
Pseudo distance correction value PR at time t5 given to the receiver 43
C (t5) becomes the pseudo distance correction value PRC (5) itself when the distance change rate correction value RRC (5) becomes substantially “0”,
Pseudo-range PR measured based on the current satellite reception signal
Differential correction process for m (t5) "PR = P"
Rm (t5) + PRC (t5) "is performed.

Then, at time t10 when 5 seconds have passed from time t5, for example, the moving body has passed a place where FM reception is not possible, so that the DARC data is not updated,
When it is determined that the GPS satellite reception time is updated every 1 second,
When the DARC data is updated at the time t5, the correction value memory 3
8. The differential correction values PRC (5), RRC stored in 8 corresponding to the GPS satellite reception time t5 at that time
(5) and the distance change rate correction value RRC itself rate of change ΔRRC “= {RRC (5) −RRC (0)} /
5 ”and the elapsed time“ 5 ”from the time t5 when the DARC data is updated to the time t10 when the satellite is currently received.
Pseudo distance correction value PRC corresponding to PS satellite reception time t10
(t10) is calculated and sent as RTCM format data to the differential data CPU 46 of the D / GPS receiver 43 (steps S1 → S2 →
S6, S5).

In this case, since the time difference between the time when the DARC data is updated at time t5 and the current satellite reception time t10 is 5 seconds, the pseudo distance correction value PRC (t10) given to the D / GPS receiver 43 at time t10. Is calculated according to the following equation (6) corresponding to the above equation (3), and the differential correction process “PR = PRm (t10) + PRC for the pseudorange PRm (t10) measured based on the satellite reception signal at the present time is calculated.
(t10) ”is performed.

PRC (t10) = PRC (5) + [RRC (5) + ΔRRC × 5] × 5 Equation (6) where ΔRRC = {RRC (5) −RRC (0)} / 5 Further, the time At time t14 when 9 seconds have passed without updating the DARC data from t5, if it is determined that the GPS satellite reception time is updated at 1 second intervals, the DARC data at time t5 is processed similarly to the processing at time t10. The differential correction value PRC stored in the correction value memory 38 at the time of update and matched with the GPS satellite reception time t5 at that time
(5), RRC (5) and distance change rate correction value RRC Change rate per unit time ΔRRC “= {RRC (5) −RR
C (0)} / 5 ", and the pseudo distance correction value PRC (t14 corresponding to the current GPS satellite reception time t14 based on the elapsed time" 9 "from the time T5 when the DARC data is updated to the current satellite reception time t14. ) Is calculated and transmitted as RTCM format data to the differential data CPU 46 of the D / GPS receiver 43 (steps S1 → S2 → S6, S5).

In this case, since the time difference between the time when the DARC data is updated at the time t5 and the current satellite reception time t14 is 9 seconds, the pseudo distance correction value PRC (t14) at the time t14 given to the D / GPS receiver 43. Is calculated according to the following equation (7) corresponding to the above equation (3), and the differential correction processing “PR = PRm (t14) + PRC for the pseudo range PRm (t14) measured based on the satellite reception signal at the present time is calculated.
(t14) ”is performed.

PRC (t14) = PRC (5) + [RRC (5) + ΔRRC × 9] × 9 Equation (7) where ΔRRC = {RRC (5) −RRC (0)} / 5 According to the differential GPS of the D / GPS receiver 43, the time data extraction unit 4
When the positioning GPS satellite reception time at 1-second intervals extracted via 0 is updated and the DARC data received by being multiplexed with the FM broadcast is updated, the DARC data is updated.
The pseudo distance correction value PR of the D / GPS data extracted from the data through the differential data extraction unit 35
C, distance change rate correction value RRC, and its correction value creation time
(t0), and based on the current GPS satellite reception time (t) extracted through the time data extraction unit 40, the differential correction value calculation unit 39 causes the pseudo distance correction value PRC (t) corresponding to the current time. , Distance change rate correction value RRC (t)
Is generated and stored in the correction value memory 38, converted into RTMC data and sent to the differential data CPU 46 of the D / GPS receiver 43, and at the same time the previous DARC data is updated (t-1), the correction value memory The change amount "RRC" between the distance change rate correction value RRC (t-1) stored in 38 and the distance change rate correction value RRC (t) corresponding to the current time.
(t) -RRC (t-1) ", and the unit time of the distance change rate correction value RRC based on the elapsed time" (t)-(t-1) "from the previous DARC update to the current DARC update The change rate ΔRRC per hit is calculated and stored in the correction value memory 38,
When the positioning GPS satellite reception time is updated without updating the DARC data, the pseudo distance correction value PRC (t-old) corresponding to the time stored in the correction value memory 38 at the time of the last DARC data update, Distance change rate correction value RRC
(t-old), the change rate ΔRC of the distance change rate correction value RRC per unit time, and the current GPS satellite reception time (t) extracted through the time data extraction unit 40, based on the pseudo distance correction value. For PRC (t-old), the distance change rate correction value RRC (t-old) and the change rate ΔRRC per unit time of the elapsed time “ΔRRC × {(t) − (t-old)}” are set. The pseudo distance correction value PRC () corresponding to the current time obtained by adding "RRC (t) {(t)-(t-old)}" for the elapsed time of the added distance change rate correction value RRC (t) corresponding to the current time. t) is calculated and R
Since it is converted into TCM data and sent to the differential data CPU 46 of the D / GPS receiver 43,
At the time of updating the DARC data, the pseudo distance PRm (t) measured by the GPS receiver 43 with the latest pseudo distance correction value PRC (t) corresponding to the current GPS satellite reception time (t).
Can be differentially corrected, and even if the DARC data is not updated, the distance change rate correction value RRC (t-old) itself from the last DARC data update (t-old) Distance change rate correction value RR corresponding to the current time in consideration of temporal change rate ΔRRC
The pseudo distance PRm (t) measured by the GPS receiver 43 can be differentially corrected by the pseudo distance correction value (t) corresponding to the current time obtained by correcting the pseudo distance correction value (t-old) by C (t).

Therefore, the pseudo distance correction value PR which is always highly accurate
The measurement pseudo distance PRm is corrected with C, and the moving position of the moving body can be measured.
Even when the update of the DARC data is lost when passing through the M unreceivable place, it is possible to always obtain the pseudo distance correction value PRC with no error and perform the highly accurate moving position measuring process.

[0074]

As described above, according to the positioning method according to the first aspect of the present invention, the time change of the distance change rate correction value RRC extracted from the DARC data is calculated, and the GPS
When the satellite reception time is updated, the current time (t) considering the temporal change of the calculated distance change rate correction value RRC
Based on the corresponding distance change rate correction value RRC (t), the immediately preceding D
The pseudo distance correction value PRC (t-old) at the time of updating the ARC data is corrected and the pseudo distance correction value PRC (t) corresponding to the current time is calculated.

Further, according to the positioning method of the second aspect of the present invention, when the DARC data multiplexed in the FM signal is updated, the pseudo distance correction value extracted from the updated DARC data. PRC and distance change rate correction value R
Time difference "(t)-(t0)" between RC and the creation time (t0) of the correction values PRC and RRC and the current GPS satellite reception time (t).
Based on the above, the pseudo distance correction value PRC (t0) is corrected by the distance change rate correction value RRC "(t)-(t0)", and the pseudo distance correction value PRC (t) corresponding to the current time is calculated and stored. At the same time, the amount of change between the distance change rate correction value RRC (t-1) at the time of the previous DARC data update and the distance change rate correction value RRC (t) at the time of the current DARC data update, and the elapsed time “(t) -(t-1) ", the temporal change of the distance change rate correction value RRC is calculated and stored, and the DARC data multiplexed in the FM signal is not updated and the GPS satellite reception time is updated. Is the pseudo distance correction value PRC (t-old) at the time calculated and stored when the DARC data was updated immediately before,
And its distance change rate correction value RRC (t-old), in consideration of the time change of the distance change rate correction value RRC calculated and stored at the time of updating the previous DARC data, the distance change rate correction value RRC (t corresponding to the current time. ), And the pseudo distance correction value PRC (t) corresponding to the current time based on the elapsed time “(t)-(t-old)” from the time when the last DARC data was updated to the current GPS satellite reception time. It will be calculated.

As a result, for example, a DARC received as FM multiplex broadcasting accompanying the passage of a place where FM reception is not possible.
Even if the update of the data is lost, it is possible to obtain a highly accurate positioning result without increasing the error of the differential correction value.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of electronic circuits of an FM multiplex receiver and a D / GPS receiver mounted on a mobile body in a differential GPS implementing a positioning system of the present invention.

[FIG. 2] DARC → R of the differential GPS
6 is a flowchart showing a differential correction value generation process performed by a differential correction value calculation unit in the TCM converter.

FIG. 3 is a diagram showing a change state of a correction value calculation result over time due to a differential correction value generation process of the differential GPS, in association with a case where update of DARC data at time t10 is missing.

FIG. 4 Differential G using FM multiplex broadcasting
The figure which shows the whole structure of PS.

FIG. 5 is a diagram showing a configuration of a DARC transmission frame multiplexed in FM broadcasting.

FIG. 6 is a diagram showing the contents of data for D / GPS assigned to two packets of the DARC transmission frame.

FIG. 7 is a diagram showing the contents of a correction data set of each satellite given as the D / GPS data.

FIG. 8: D / G mounted on a conventional D / GPS mobile unit
The block diagram which shows the structure of PS receiver and FM multiplex receiver.

FIG. 9 is a flowchart showing a differential correction value generation process in the conventional D-GPS DARC → RTCM converter.

FIG. 10 is a diagram showing a change state of a differential correction value calculation result with the lapse of time in the conventional D / GPS.

FIG. 11 is a diagram showing a change state of the differential correction value calculation result with the lapse of time when the update of the DARC data at time t10 is missing in the conventional D / GPS.

[Explanation of symbols]

11 ... D / GPS fixed reference station, 12a, 12b, ... GP
S satellite, 13 ... FM multiplex DARC data control unit, 14 ...
Modulator, 15 ... transmitter of FM station, 16 ... transmitting antenna,
17 ... Moving object, 31 ... FM antenna, 32 ... FM tuner, 33 ... FM multiplex decoder, 34 ... DARC → RTC
M converter, 35 ... Differential data extraction unit, 3
6 ... PRC extraction part, 37 ... RRC extraction part, 38 ... Correction value memory, 39 ... Differential correction value calculation part, 40
... Time data extraction unit, 41 ... Data formatter, 42
… GPS antenna, 43… GPS receiver, 44… GP
S sensor, 45 ... Positioning CPU, 46 ... Differential data CPU, 47 ... Monitor.

Claims (2)

[Claims] 1. A first correction data and positioning information measured based on signals received from a plurality of satellites, which are extracted from multiplexed data that is updated and multiplexed into an FM signal at regular intervals. In a positioning method for performing correction based on second correction data indicating a rate of change of the first correction data per unit time, a second correction for calculating a temporal change of the second correction data extracted from the multiplex data. When the data change calculation means and the satellite reception time for measuring the positioning information are updated,
The second calculated by the second correction data change calculation means
Positioning data correction means for correcting the first correction data on the basis of the second correction data considering the temporal change of the correction data and calculating the correction data of the positioning information. method. 2. The first correction data and positioning information measured based on signals received from a plurality of satellites and extracted from multiplexed data that is updated and multiplexed into an FM signal at fixed time intervals. In a positioning method for performing correction based on second correction data indicating a rate of change of the first correction data per unit time, when the multiplex data multiplexed into the FM signal is updated, the updated multiplex data is updated. Based on the first and second correction data extracted from the data, and the time difference between the creation time of the correction data and the current positioning information measurement satellite reception time, the first correction data is converted into the second correction data. Correction data calculation means for updating the multiplex data for calculating the correction data of the positioning information corresponding to the current measurement time, and the positioning calculated by the correction data calculation means for updating the multiplex data. Correction data storage means for storing report correction data together with second correction data; and second correction data extracted from the updated multiple data when the multiple data multiplexed in the FM signal is updated. And the amount of change between the second correction data stored in the correction data storage means at the time of the previous multiplex data update, and the elapsed time from the time of the previous multiplex data update to the current multiplex data update. Second correction data change calculation means for calculating the change over time of the correction data, and second calculation data calculated by the second correction data change calculation means.
Second correction data change storage means for storing the change over time of the correction data, and the multiplexed data multiplexed on the FM signal is not updated,
When the satellite reception time for measuring the positioning information is updated,
The positioning information correction data at that time stored in the correction data storage means corresponding to the time of updating the multiplex data, and the second correction data stored in the correction data storage means to the second correction data change storage means. Based on the second correction data corresponding to the current time in consideration of the temporal change of the stored second correction data, and the elapsed time from the time of updating the multiplex data to the satellite reception time for measuring the current positioning information, A positioning method, comprising: a correction data calculation means when the multiplex data is not updated, which calculates correction data of the positioning information corresponding to the current measurement time.