JPH06342054A - Gps receiver - Google Patents

Abstract

PURPOSE:To provide a GPS receiver which can compute a precise position even when new ephemeris data is received earlier than by a reference station. CONSTITUTION:First pseudo-range correction value information and second pseudo-range correction value information which have been operated on the basis of latest ephemeris data and ephemeris data just before it are received by a pseudo-range correction value reception part 22 together with ephemeris data generation time information. The latest ephemeris data and the ephemeris data just before it which includes ephemeris data generation time information obtained by an ephemeris measurement part 17 are stored in a first ephemeris storage part 19 and a second ephemeris storage part 24. Pseudo-range data obtained by a pseudo-range measurement part 18 is corrected by the first pseudo-range correction value information and the second pseudo-range correction value information in a pseudo-range correction part 20. A position signal is operated in a position computation part on the basis of the ephemeris data with reference to the ephemeris generation time information which coincides with the ephemeris generation time information stored in the first and second ephemeris storage parts 19, 24 and on the basis of the corrected pseudo-range data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a GPS receiver for measuring a position by using a GPS reception signal, and more particularly to a GPS receiver with improved measurement position accuracy.

[0002]

2. Description of the Related Art Conventionally, regarding the correction of the measurement position of a GPS receiver, the US RTCM (Radio
Technical Commission for Maritime Services), the correction method, data format, etc. are described in “RTCM RECOMMENDED STANDARDS FOR DIFFERENTIAL NAVS
It is made public by the document "TAR GPS SERVICE".

Based on this material, a conventional technique will be described with reference to FIG.

First, the reference station A for calculating the position correction value will be described. It is assumed that the reference station A knows the exact position of the GPS receiving antenna 2, and the accurate position information of the GPS receiving antenna 2 is stored in the reference station position storage unit 12. The GPS receiving antenna 2 receives a signal (referred to as a GPS signal) from the GPS satellite 1 and outputs the GPS signal to the GPS signal receiving unit 3. The GPS signal receiving unit 3 receiving the GPS signal divides the GPS signal into a pseudo distance measuring signal and a signal for measuring satellite orbit information called ephemeris data, and the GPS signal receiving unit 3 separates the pseudo distance measuring unit 5 from the GPS signal receiving unit 3. Is output to the ephemeris measurement unit 4.

Due to the configuration of the GPS system, the ephemeris data is updated once every one hour or two hours, and the time at which the ephemeris data is generated by the GPS system (referred to as the ephemeris data generation time) is included as part of the ephemeris data. The ephemeris data obtained from the measurement signal of the orbit information by the ephemeris measurement unit 4 is normally stored in the first ephemeris storage unit 6 only at this update. Prior to this storage, at the time of updating, the ephemeris data previously stored in the first ephemeris storage unit 6 is stored in the second ephemeris storage unit 9.

On the other hand, theoretical pseudo distance data is calculated by the first theoretical pseudo distance calculation unit 7 from the position information output from the reference station position storage unit 12 and the ephemeris data output from the first ephemeris storage unit 6. It This is the first theoretical pseudo range data. The pseudo distance measurement unit 5 calculates pseudo distance data based on the pseudo distance measurement signal output from the GPS signal receiving unit 3. Based on the first theoretical pseudo distance data output from the first theoretical pseudo distance calculation unit 7 and the pseudo distance data output from the pseudo distance measurement unit 5, the first pseudo distance correction value calculation unit 8 calculates both of them. The difference is calculated. This is the first pseudo distance correction value. The first pseudo distance correction value is transmitted from the pseudo distance correction value transmission unit 13 to the mobile station via the correction value transmission antenna 14 together with the corresponding ephemeris data generation time information.

The ephemeris data is updated once every one hour or two hours as described above.
Only during a few minutes from the time of this update, the pseudo distance correction value transmission unit 13 together with the first pseudo distance correction value described above together with the ephemeris data generation time information corresponding to the second pseudo distance correction value described below. Correction value transmission antenna 1 via
4 to the mobile station.

Next, the calculation of the second pseudo distance correction value will be described. The second theoretical pseudo distance calculation unit 10 calculates theoretical pseudo distance data from the position information output from the reference station position storage unit 12 and the ephemeris data output from the second ephemeris storage unit 9. This is the second theoretical pseudo range data. Second theoretical pseudo distance calculation unit 10
From the second theoretical pseudo distance data output from the pseudo distance measurement unit 5 and the pseudo distance data output from the pseudo distance measurement unit 5, the second pseudo distance correction value calculation unit 11 calculates the difference between the two.
This is the second pseudo distance correction value. This second pseudo distance correction value is transmitted from the pseudo distance correction value transmission unit 13 to the mobile station B1 via the correction value transmission antenna 14 together with the corresponding ephemeris data generation time.

Next, the mobile station B1 which is a GPS receiver will be described. The GPS receiving antenna 15 receives the GPS signal from the same GPS satellite 1 as that of the reference station A, and outputs the signal to the GPS signal receiving unit 16. GPS signal receiver 16
Divides the received GPS signal into a pseudo distance measurement signal and an ephemeris measurement signal, and from the GPS signal receiving unit 16,
These are output to the pseudo distance measuring unit 18 and the ephemeris measuring unit 17, respectively.

As described above, since the ephemeris data is updated once every 1 hour or 2 hours, the ephemeris data obtained from the ephemeris measurement signal by the ephemeris measuring unit 17 is used only at this time. Store in 19.

On the other hand, the correction value transmitting antenna 14 of the reference station A
The first and second pseudo-range correction values transmitted by the pseudo-range correction value receiving unit 22 together with the corresponding ephemeris data generation times are received by the pseudo-range correction value receiving unit 22 via the correction value receiving antenna 23 of the mobile station B1. .

The pseudo distance measuring unit 18 receiving the output of the GPS signal receiving unit 16 measures the pseudo distance data.
After confirming that the ephemeris data generation time information transmitted from the reference station A matches the ephemeris data generation time information stored in the ephemeris storage unit 19, the pseudo distance data output from the pseudo distance measurement unit 18 is corrected with the pseudo distance correction. The correction is performed by the pseudo distance correction value output from the pseudo distance correction value receiving unit 22 in the unit 20. The position calculation unit 21 calculates the position of the mobile station B1 based on the corrected pseudo distance data output from the pseudo distance correction unit 20 and the ephemeris data output from the ephemeris storage unit 19. At this time, the error concerning the position of the orbit information included in the ephemeris data and the error of the measured pseudorange data due to the propagation delay due to the ionosphere are calculated by the reference station A as a pseudorange correction value based on the accurate position of the reference station A, It is transmitted to the mobile station B1 and used for correction of the pseudo range data of the mobile station B1. Therefore, the mobile station B1
Accurate position information that does not include these errors is calculated by the position calculator
It can be calculated by 1.

Next, the reason why the reference station A transmits the second pseudo distance correction value together with the first pseudo distance correction value for several minutes when updating the ephemeris data will be described. Since the reference station A is usually installed in a place where the GPS satellites can be seen well, the reference station A receives the GPS signal earlier than the mobile station B1 in which the visibility of some satellites is easily masked in a building or the like for the same GPS satellite signal. You may be able to. In this case, when the ephemeris data is updated, the reference station A transmits the correction value based on the new ephemeris data to the mobile station B1 as the first pseudo distance correction value, but the mobile station B1
Has not received new ephemeris data and cannot correct it.

In order to avoid this problem,
The reference station A calculates a correction value based on the old ephemeris data stored in the second ephemeris storage unit 9, and sends it to the mobile station B1 as a second pseudo distance correction value together with the first pseudo distance correction value. In this case, the mobile station B1 corrects using the second pseudo distance correction value until new ephemeris data is received, and uses the first pseudo distance correction value when new ephemeris data is received.

Conventionally, since this type of apparatus is configured as described above, for example, when the mobile station moves to a place with a better view of GPS satellites than the reference station, and the mobile station B1 updates the ephemeris data. When new ephemeris data is received first, the ephemeris storage unit 19 stores new ephemeris data. Moreover, the reference station A
Since the pseudo distance correction value corresponding to the new ephemeris data is not transmitted from, there is a problem that the pseudo distance data cannot be corrected.

[0016]

SUMMARY OF THE INVENTION According to the present invention, even if a mobile station, which is a GPS receiver, receives new ephemeris data before the reference station, it can correct the pseudorange and calculate an accurate position. The purpose is to provide a receiver.

[0017]

A GPS receiver according to the present invention is a GPS receiver as a mobile station that receives transmission correction value information from a reference station and calculates its own position. First theoretical range correction calculated based on the latest ephemeris data obtained from the received GPS signal at the first base station and the first pseudo range correction calculated based on the pseudo range signal obtained from the received GPS signal at the reference station. Value information is received together with the latest ephemeris data generation time information, and the second theoretical pseudo distance information and the pseudo distance signal are calculated based on the reference station position information and the ephemeris data immediately before the latest ephemeris data. A correction value information receiver for receiving the second pseudo distance correction value information calculated based on the information together with the immediately preceding ephemeris data generation time information. And storage means for storing the latest femmelis data obtained from the GPS signal received by the mobile station and the ephemeris data immediately before the latest ephemeris data together with the respective generation time information, and pseudo from the GPS signal received by the mobile station. The pseudo distance calculation means for calculating a distance signal and the pseudo distance correction value information received by the mobile station together with the ephemeris generation time information received by the mobile station that matches the ephemeris generation time information stored in the storage means Position calculating means for correcting the pseudo-range signal calculated in the station and calculating a position signal corresponding to the position of the mobile station based on the corrected pseudo-range signal.

The position calculating means in the GPS receiver of the present invention is such that when each ephemeris generation time stored in the memory means and the ephemeris generation time information received by the mobile station match, the generation time of the earlier ephemeris is generated. The pseudo distance correction value information received by the mobile station together with the time information is used as the pseudo distance correction value information for calculation.

[0019]

According to the GPS receiver of the present invention, the first pseudo-distance correction value information together with the latest ephemeris data generation time information and the second pseudo distance correction time information based on the ephemeris data generation time immediately before the latest ephemeris data generation time. The pseudo distance correction value information of is received by the correction value information receiving means.

On the other hand, the latest femeris data obtained from the GPS signal received by the mobile station and the ephemeris data immediately before the latest ephemeris data are stored in the storage means together with the generation time information.

A pseudo range signal is calculated by the pseudo range calculation means from the GPS signal received by the mobile station.

Based on these, the position calculation means
By the pseudo distance correction value information received by the mobile station together with the ephemeris generation time information received by the mobile station that matches the ephemeris generation time information stored in the storage means, the pseudo distance signal calculated by the pseudo distance calculation means is corrected, A position signal corresponding to the position of the mobile station is calculated based on the corrected pseudo range signal.

Therefore, even if the mobile station first receives new ephemeris data, the pseudo distance can be corrected and the accurate position of the mobile station can be calculated.

Further, when each ephemeris generation time stored in the memory means and the ephemeris generation time information received by the mobile station respectively match, the generation time is the pseudo distance received by the mobile station together with the earlier ephemeris generation time information. Since the correction value information is used for position signal calculation, the pseudo distance is corrected by the latest pseudo distance correction value information,
The exact position of the mobile station can be calculated.

[0025]

FIG. 1 is a block diagram showing an embodiment of the present invention.

Reference numeral 1 indicates a GPS satellite, and A indicates a reference station. The reference station A has the same configuration as that shown in FIG.
2 is a GPS receiving antenna, 3 is a GPS signal receiving unit, 4 is an ephemeris measuring unit, 5 is a pseudo distance measuring unit, 6 is a first ephemeris storage unit, 7 is a first theoretical pseudo distance calculating unit,
Reference numeral 8 is a first pseudo distance correction value calculation unit, 9 is a second ephemeris storage unit, 10 is a second theoretical pseudo distance calculation unit, 11 is a second pseudo distance correction value calculation unit, and 12 is a reference station position storage unit. , 13 are pseudo-range correction value transmitting units, and 14 is a correction-value transmitting antenna, which transmits the first pseudo-range correction value and the second pseudo-range correction value. Next, reference numeral B indicates a mobile station which is the GPS receiver of this embodiment. Mobile station B is GPS
The reception antenna 15, the GPS signal reception unit 16, the ephemeris measurement unit 17, the pseudo distance measurement unit 18, the first ephemeris storage unit 19, the pseudo distance correction value reception unit 22, and the correction value reception antenna 23 are provided. It has the same configuration as the mobile station B1.

In the GPS receiver of this embodiment, the pseudo distance correction section 20, the position calculation section 21A and the second section are further provided.
The ephemeris storage unit 24 is provided. When the memory of the first ephemeris storage unit 19 is updated, the ephemeris data stored in the first ephemeris storage unit 19 until then is transferred to and stored in the second ephemeris storage unit 24. Further, in the pseudo distance correction unit 20, the pseudo distance data measured by the pseudo distance measuring unit 18 is corrected by the first and second pseudo distance correction values received by the pseudo distance correction value receiving unit 22. Position calculator 21
In A, one of the pseudo distance data corrected by the pseudo distance correction unit 20 by the first and second pseudo distance correction values and the first ephemeris storage unit 19 are used.
The position information is calculated using one of the stored ephemeris data and the ephemeris data stored in the second ephemeris storage unit 24.

This calculation is performed by the first ephemeris storage unit 1 which matches the ephemeris data generation time information carried by the pseudo distance data corrected by the pseudo distance correction value.
9 selects the ephemeris data generation time information of the stored ephemeris data or the ephemeris data generation time information of the ephemeris data stored in the second ephemeris storage unit 24, and the pseudo distance data and the ephemeris data having the same ephemeris data generation time information are selected. The position signal corresponding to the position of the mobile station B is calculated by and.

Further, when the ephemeris data generation time information for the two ephemeris data and the ephemeris data generation time information carried by the corrected pseudo distance data respectively match, the ephemeris data of the earlier generation time and the corresponding ephemeris data A position signal is calculated from the corrected pseudo distance data.

Next, the operation of the GPS receiver of this embodiment will be described.

Since the operations of the GPS satellite 1 and the reference station A are exactly the same as those described in the conventional art, the description thereof will be omitted.

Next, the operation of the mobile station B which is a GPS receiver will be described.

The GPS receiving antenna 15 receives the same GPS satellite 1 signal as the reference station A, and the GPS signal receiving section 16
Output a signal to. The GPS signal receiving unit 16 divides the signal into a pseudo distance measuring signal and a trajectory information measuring signal, and outputs the signals to the pseudo distance measuring unit 18 and the ephemeris measuring unit 17, respectively.

As described above, the ephemeris data is 1
Since it is updated once in time or every two hours, the ephemeris data obtained by the ephemeris measurement unit 17 is stored in the first ephemeris storage unit 19 at the time of updating. In addition,
Prior to this storage, at the time of updating, the ephemeris data previously stored in the first ephemeris storage unit 19 is transferred to and stored in the second ephemeris storage unit 24.

On the other hand, the correction value transmitting antenna 14 of the reference station A
The first and second pseudorange correction values transmitted from the mobile station B together with the corresponding ephemeris data generation time information.
It is received by the pseudo distance correction value receiving unit 22 via the correction value receiving antenna 23.

The pseudo distance measuring unit 18 measures the pseudo distance data based on the output of the GPS signal receiving unit 16. The pseudo distance data measured by the pseudo distance correction unit 20 is corrected individually by the first and second pseudo distance correction values received by the pseudo distance correction unit 20.

The position calculator 21A searches the corrected pseudo-range data for ephemeris data having ephemeris data generation time information that matches the ephemeris data generation time information for the corrected pseudo-range data. A position signal corresponding to the position of the mobile station B is calculated on the basis of the ephemeris data and the corrected pseudo range data with which the information matches.

In this case, the position signal is calculated even if there is a difference between the reception time of the ephemeris data at the mobile station B and the reception time of the ephemeris data at the reference station A.

That is, when the mobile station B which is a GPS receiver receives the ephemeris data earlier than the reference station A, the pseudo distance correction value corresponding to the old ephemeris data transmitted from the reference station A and the second Using the old ephemeris data stored in the ephemeris storage unit 24, the position signal is calculated in the mobile station B, and the accurate position of the mobile station B can be obtained.

On the contrary, when the reference station A receives the ephemeris data earlier than the mobile station B, the reference station A receives the ephemeris data until the mobile station B receives new ephemeris data.
By using the pseudo-range correction value corresponding to the old ephemeris data transmitted from the mobile station B and the ephemeris data before the new ephemeris data is received in the mobile station B (stored in the first ephemeris storage unit 19 in this case). The position signal can be calculated in station B to obtain the exact position of mobile station B. Further, after the mobile station B receives the new ephemeris data, the mobile station B uses the pseudo distance correction value corresponding to the new ephemeris data transmitted from the reference station A and the new ephemeris data received by the mobile station B at the position signal at the mobile station B. Is calculated and mobile station B
The exact position of can be obtained.

When the mobile station B and the reference station A simultaneously receive the ephemeris data, the pseudo distance correction value corresponding to the new ephemeris data transmitted from the reference station A and the first ephemeris storage unit 19 of the mobile station B are received. Mobile station B using the new ephemeris data stored in
The position signal is calculated at to obtain the accurate position of the mobile station B.

In the above-described embodiment, the pseudo distance data is corrected by the pseudo distance correction unit 20 according to the received first and second pseudo distance correction values, and the corrected two pseudo distance data and the ephemeris data are obtained. An example is given in which the position calculation unit 21A searches for a match in the ephemeris data generation time information of 1 to calculate the position signal.

However, the pseudo distance correction unit 20 searches for the first or second pseudo distance correction value with which the ephemeris data generation time information of the ephemeris data stored in the first and second ephemeris storage units 19 and 24 matches. Then, the pseudo distance data is corrected by the retrieved pseudo distance correction value, and the position is determined by the corrected pseudo distance data and the ephemeris data having the same ephemeris data generation time information as the ephemeris data generation time information for the pseudo distance data. The position signal may be calculated in the calculator 21A.

[0044]

As described above, according to the present invention, G
Even if the mobile station, which is a PS receiver, receives new ephemeris data before the reference station, it is possible to obtain the accurate position of the mobile station by using the pseudorange correction value transmitted from the reference station. Yes, it is extremely effective for systems such as car navigation systems that always require accurate positions.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a conventional example.

[Explanation of symbols]

 A ... Base station B ... Mobile station 1 ... GPS satellite 2, 15 ... GPS receiving antenna 3, 16 ... GPS signal receiving unit 4, 17 ... Ephemeris measuring unit 5, 18 ... Pseudo distance measuring unit 6, 19 ... First ephemeris memory Part 7 ... 1st theoretical pseudo distance calculation part 8 ... 1st pseudo distance correction value calculation part 9, 24 ... 2nd ephemeris storage part 10 ... 2nd theoretical pseudo distance calculation part 11 ... 2nd pseudo distance correction Value calculation unit 12 ... Reference station position storage unit 13 ... Pseudo distance correction value transmission unit 14 ... Correction value transmission antenna 20 ... Pseudo distance correction unit 21, 21A ... Position calculation unit 22 ... Pseudo distance correction value reception unit 23 ... Correction value reception antenna

Claims (2)

[Claims] 1. A GPS receiver as a mobile station that receives transmission correction value information from a reference station and calculates its own position, wherein the latest ephemeris data obtained from a reference station position and a GPS signal received at the information reference station. Based on the first theoretical pseudorange information calculated based on the first theoretical pseudorange information and the pseudorange signal obtained from the GPS signal received at the reference station, together with the latest ephemeris data generation time information. Second theoretical pseudo distance information received and calculated based on the reference station position information and the ephemeris data immediately before the latest ephemeris data, and second pseudo distance correction value information calculated based on the pseudo distance signal Obtained from the GPS signal received by the mobile station, and correction value information receiving means for receiving the above-mentioned immediately preceding ephemeris data generation time information. Storage means for storing new ephemeris data and ephemeris data immediately before the latest ephemeris data together with respective generation time information; and pseudo distance calculation means for calculating a pseudo distance signal from the received GPS signal at the mobile station, The pseudo distance signal calculated by the mobile station is corrected by the pseudo distance correction value information received by the mobile station together with the ephemeris generation time information received by the mobile station that matches the ephemeris generation time information stored in the storage means. A GPS receiver, comprising: position calculating means for calculating a position signal corresponding to the position of the mobile station based on the corrected pseudo range signal. 2. The GPS receiver according to claim 1, wherein when the ephemeris generation time stored in the storage means matches the ephemeris generation time information received by the mobile station, the generation time is earlier. A GPS receiver, wherein pseudo distance correction value information received by a mobile station together with the other ephemeris generation time information is used as pseudo distance correction value information for calculation.