JP5357451B2 - Multi-frequency GNSS receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multi-frequency GNSS (Global Navigation Satellite System) receiving device for performing positioning operation efficiently and effectively by acquiring a positioning pseudo distance by utilizing a positioning signal of the second signal form of the first satellite, or of some data channel signal form of the second satellite, even when the positioning pseudo distance cannot be obtained relative to the first signal form of the first satellite. <P>SOLUTION: When the positioning pseudo distance cannot be obtained from a positioning signal of the first signal form of the first satellite, a lower order part of a pseudo distance below a prescribed distance is determined from an obtained pseudo distance, and then integrated with an upper order part obtained from a signal form of the satellite or a positioning signal of another satellite, to thereby generate the positioning pseudo distance. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

The present invention relates to a positioning apparatus that receives positioning signals in a plurality of signal formats transmitted from a Global Navigation Satellite System (GNSS) satellite and obtains a position.

With the modernization of GPS, it is planned to broadcast the L2 band L2C signal and the L5 band L5 signal from the same satellite in addition to the conventional L5 band L1-C / A signal. When signals of various modulation formats are broadcast from the same satellite in a plurality of frequency bands, it is effective for calculation processing, accuracy, and early positioning to use positioning signals of a plurality of signal formats.

The GPS L1-C / A signal is phase-modulated with a C / A spreading code with a repetition period of 1 msec and a navigation message with a bit rate of 50 bps. Since the navigation message is transmitted by dividing a 1500-bit frame into five subframes, the top of each 300-bit subframe arrives every 6 seconds. In the case of the L1-C / A signal, the bit period of the navigation message in the subframe is 20 msec, and the C / A code is repeated 20 times during this period.

In the GPS L2C signal, a data channel L2CM signal on which a navigation message is superimposed and a pilot channel L2CL signal without a navigation message are transmitted in a time division manner. The L2CM signal is modulated with a spreading code with a period of 20 msec and a navigation message with a bit rate of 25 bps (symbol rate 50 sps). Since the navigation message is composed of 300-bit (600 symbols) subframes and has a bit period of 40 msec (symbol period of 20 msec), the head of each subframe arrives every 12 seconds. The L2CL signal is modulated with a spreading code having a period of 1.5 sec.

The GPS L5 signal has a configuration in which the data channel signal L5I signal and the pilot channel signal L5Q signal are orthogonal to each other. L5I signal, and I5 spreading code repetition period 1 msec, modulated by 10-bit NH ₁₀ codes the bit rate 1 Kbps, is modulated further navigation message 50 bps (symbol rate 100 SPS). The repetition period of the NH ₁₀ code is 10 msec, and the bit period of the navigation message is 20 msec. Since the navigation message is composed of 300-bit (600 symbols) subframes and has a bit period of 20 msec (symbol period of 10 msec), the head of each subframe arrives every 6 seconds.

The L5Q signal is modulated with an L5Q spreading code with a repetition period of 1 msec, and further modulated with a 20-bit NH ₂₀ code with a bit rate of 1 msec. The repetition period of the NH ₂₀ code is ₂₀ msec.

As described in Patent Document 1 and Patent Document 2, the basic concept of GNSS positioning can calculate the pseudo distance between the satellite and the receiver by knowing the transmission time of the positioning signal of the satellite and the reception time of the receiver. . The reception time is obtained by measuring the peak position of the correlation value between the spread code and the replica code by measuring the receiver clock. The transmission time is obtained by knowing the HOW word information included in the subframe and the elapsed time from the top bit time of the subframe to the correlation peak position. For this purpose, after synchronization of the spread code, bit synchronization of the navigation message (hereinafter referred to as bit synchronization) is performed, and finally subframe synchronization (hereinafter referred to as frame synchronization) processing is required.

Taking the case of the L1-C / A signal as an example, a method for calculating the transmission time will be described with reference to FIG. In FIG. 4, when the HOW word is demodulated in synchronization with the subframe, the transmission time Thow of the subframe head bit at the GPS time is known. Tcor is the time of the peak position of the code correlation measured with the receiver clock, and this peak position is assumed to be in the bit period of the (m + 1) th navigation message.

Since subframes, navigation message bits, and C / A codes are synchronized, of the elapsed time from the time Thow to the peak position of the code correlation, the time Tbit that is an integral multiple of 20 msec counts the number of bits after bit synchronization. To understand. The fraction of 20 msec can be obtained by counting the number of C / A code repetitions to obtain a time Tcode that is an integral multiple of 1 msec. The time Tchp of less than 1 msec can be found by C / A code correlation processing.

As a result, the transmission time Ttrn can be calculated by Thow + Tbit + Tcode + Tchp. From the reception time Tcor and the transmission time Ttrn, the pseudo distance can be calculated by (Tcor-Ttrn) × light speed. Since Tcor is measured by the receiver clock and is not synchronized with GPS time, it is offset from GPS time. This reception clock offset is estimated together with the receiver position and speed in the navigation calculation process.

The above is an explanation of the case of the L1-C / A signal, but the pseudorange can be calculated in the same way with other signal formats (L2CM signal, L5I signal). However, in any signal format, because of the frame synchronization, if the transmission time Ttrn cannot be obtained, the pseudorange used for positioning (hereinafter referred to as the pseudorange for positioning) cannot be obtained. Can not do it.

In a normal receiver, if the received radio wave is strong, frame synchronization can be obtained, but if the received radio wave is weak, code synchronization can be obtained, but bit synchronization and frame synchronization may not be obtained. In this case, unless frame synchronization is established, Thow is unknown, so a positioning pseudorange cannot be obtained and positioning calculation cannot be performed.

Even if frame synchronization is achieved, since the subframe period is 6 seconds, it takes at least 6 seconds to demodulate the HOW word, and it takes time to obtain a positioning result. In order to overcome these drawbacks, Patent Document 1 and Patent Document 2 described above present a technique for performing positioning from pseudorange information obtained by code synchronization without performing bit synchronization or frame synchronization.

U.S. Patent No. 7,064,709 JP2001-59864

However, although the technique of Patent Document 1 can perform positioning only by code synchronization, it requires at least five satellites. In particular, the need for five satellites in an environment where received radio waves are weak is a severe limitation. Since the technique of Patent Document 2 is a method of measuring the spread code period or the time of the bit transition timing of the navigation message from the clock of the GPS receiver, when measuring the boundary of the spread code period, the receiver clock is 0. It is necessary to measure with an accuracy of 5 msec or less. This requirement is a severe constraint in providing a particularly inexpensive general purpose receiver.

In known techniques including Patent Document 1 and Patent Document 2, if frame synchronization cannot be achieved in the first signal format of the first satellite, it is decided to give up calculating the pseudorange for the signal format of the satellite, A pseudorange for the first signal format of another satellite is obtained. In this case, a loss due to a decrease in the number of observations of the positioning pseudo-range may be incurred, or positioning may not be possible.

Further, in the conventional receiver, the pilot channel signal on which the navigation message is not superimposed is not used for obtaining the positioning pseudo distance because the positioning pseudo distance cannot be obtained.

The present invention has been made in view of the above problems, and by using positioning signals of a plurality of signal formats including not only data channels but also pilot channels, positioning is performed with respect to the first signal format of the first satellite. Multi-frequency GNSS that performs efficient and effective positioning calculations by obtaining positioning pseudoranges using positioning signals in other signal formats or other satellite signal formats even when pseudoranges cannot be obtained An object is to provide a receiving apparatus.

In order to solve the above-mentioned problem, the present invention receives a positioning signal of a plurality of signal formats transmitted from the same satellite and outputs at least a position in a multi-frequency GNSS receiver that converts the positioning signals of the plurality of signal formats. A code synchronization unit that performs synchronization processing on the included spreading code, a bit synchronization unit that performs synchronization processing on the bits of the navigation message included in the positioning signal in the signal format, and a frame synchronization unit that performs synchronization processing on the frames of the navigation message Obtained from the pseudo distance adjustment unit, a pseudo distance adjustment unit that adjusts to obtain a positioning pseudo distance based on pseudo distance information obtained from the code synchronization unit, the bit synchronization unit, and the frame synchronization unit. A positioning calculation unit that performs positioning calculation based on the pseudo distance for positioning,
The pseudorange adjustment unit, when the pseudorange with respect to the positioning signal of the first signal format of the first satellite is not a pseudorange for positioning obtained from the frame synchronization unit, a subordinate portion less than a predetermined distance from the pseudorange And obtaining an upper part that is greater than or equal to the predetermined distance from a pseudo distance for positioning with respect to a positioning signal in the second data channel signal format of the first satellite, and combining the upper part and the lower part. It is characterized in that it is a pseudo distance for positioning for one signal format.
Further, in a multi-frequency GNSS reception method for receiving positioning signals of a plurality of signal formats transmitted from the same satellite and outputting at least a position, synchronization processing is performed on spreading codes included in the positioning signals of the plurality of signal formats. A step of performing synchronization processing on the bits of the navigation message included in the positioning signal of the signal format, a step of performing synchronization processing on the frame of the navigation message, the spreading code, the bits of the navigation message, and the navigation A step of adjusting so as to obtain a pseudo distance for positioning based on pseudo distance information obtained by a synchronization process to a frame of a message, and a step of performing a positioning calculation based on the pseudo distance for positioning,
If the pseudo distance to the positioning signal of the first signal format of the first satellite is not the pseudo distance for positioning obtained by the synchronization processing to the frame of the navigation message, a lower part less than a predetermined distance is obtained from the pseudo distance. , Obtaining a higher order part of the predetermined distance or more from a pseudo distance for positioning with respect to a positioning signal of the second data channel signal format of the first satellite, and combining the higher order part and the lower order part with the first part. It is characterized by the pseudo distance for positioning with respect to the signal format.

The predetermined distance is a distance corresponding to a cycle of the shortest spread code among the positioning signals of a plurality of signal formats to be used. By setting the predetermined distance to the cycle of the spreading code with the highest synchronization probability, pseudo distance information corresponding to the cycle of the shortest spreading code is always obtained, and this can be used for positioning.

The present invention also provides a multi-frequency GNSS receiver that receives positioning signals of a plurality of signal formats transmitted from the same satellite, and outputs at least a position, in a spreading code included in the positioning signals of the plurality of signal formats. A code synchronization unit that performs synchronization processing, a bit synchronization unit that performs synchronization processing on bits of the navigation message included in the positioning signal in the signal format, a frame synchronization unit that performs synchronization processing on a frame of the navigation message, and the code synchronization A pseudo-range adjusting unit that adjusts so as to obtain a positioning pseudo-range based on pseudo-range information obtained from the bit synchronizing unit and the frame synchronizing unit, and a positioning pseudo-range obtained from the pseudo-distance adjusting unit. A positioning calculation unit that performs positioning calculation based on
The pseudo distance adjusting unit obtains a lower part less than a predetermined distance from the pseudo distance when the pseudo distance with respect to the positioning signal of the first signal format of the first satellite is not the pseudo distance for positioning obtained from the frame synchronization unit. In addition, an upper part that is equal to or greater than the predetermined distance is obtained from a positioning pseudo distance for a positioning signal of any data channel signal format of the second satellite, and the combination of the upper part and the lower part is performed in the first signal. It is a pseudo distance for positioning with respect to the format. Thereby, the unambiguous unification of pseudoranges in a multi-frequency, multi-signal format can be easily performed.

As a result, even when the positioning pseudorange cannot be obtained with respect to the first signal format of the first satellite, the positioning pseudorange is obtained by using the positioning signal in the data channel signal format of the second satellite. Thus, an efficient and effective positioning calculation can be performed.

Further, the present invention is characterized in that the first signal format of the first satellite may be either a data channel or a pilot channel. As a result, a higher spreading code correlation gain can be expected compared to the spreading code of the data channel signal format, which is advantageous in terms of positioning accuracy and performance. Further, since at least the frame synchronization processing can be deleted, not only the positioning signal tracking control processing load can be reduced, but also positioning calculation can be performed without waiting for the time required for the frame synchronization processing.

In addition, the present invention provides a positioning in the data channel signal format of one of the second satellites when the pseudorange for the positioning signal in the first signal format of the first satellite is not the positioning pseudorange obtained from the frame synchronization unit. In the case of obtaining a high-order part that is equal to or greater than a predetermined distance from the positioning pseudo-range for the signal, the predetermined distance is a distance corresponding to 20 msec.

In addition, the present invention provides a positioning in the data channel signal format of one of the second satellites when the pseudorange for the positioning signal in the first signal format of the first satellite is not the positioning pseudorange obtained from the frame synchronization unit. When obtaining a high-order part that is greater than or equal to a predetermined distance from the positioning pseudo-range for the signal, the predetermined distance is a pseudo-range obtained by code synchronization or bit synchronization of the positioning signal of the first signal format of the first satellite, It is determined based on whether or not the maximum distance deviation of the geometric distance between each satellite used for positioning and the receiver is included.

According to the present invention, when only a lower part less than a predetermined distance is obtained with respect to the positioning signal of the first signal format of the first satellite, the upper part of the positioning pseudo-range for a predetermined time or more is By obtaining from the positioning signal of the second signal format of one satellite or the data channel signal format of any of the second satellites, the loss of the number of observations of the positioning pseudorange is prevented or the number of observations is increased. be able to. As a result, an improvement in positioning rate and positioning accuracy can be expected.

Further, according to the present invention, when only a lower part less than a predetermined distance is obtained with respect to the positioning signal of the first signal format of the first satellite, the upper part of the positioning pseudo-range for a predetermined time or more is Opportunity to perform positioning calculations independently for positioning signals of signal formats of a plurality of frequencies by obtaining from positioning signals of the second signal format of the first satellite or the data channel signal format of any of the second satellites Increase. As a result, improvement in positioning accuracy can be expected.

For example, when four satellites are used for positioning, four positioning pseudoranges can be obtained for the signal format of the L2 frequency band, but only three positioning pseudoranges can be obtained in the L1 frequency band. By supplementing the upper part of the positioning pseudo distance that is insufficient in the L1 frequency band with the upper part of the positioning pseudo distance obtained in the L2 frequency band, four positioning pseudo distances are obtained in the L1 frequency band.

Further, according to the present invention, when a positioning operation is uniquely performed on a positioning signal of a signal format of a plurality of frequencies, only the lower part of the pseudorange is obtained in the signal format of one frequency band, and the higher rank of the positioning pseudorange By obtaining the part from the signal format of the other frequency band, in the signal format of the frequency band obtained from the lower part, the bit synchronization or frame synchronization processing can be omitted, so that the processing time can be reduced and the processing time can be shortened.

In addition, according to the present invention, since only the lower part of the pseudorange less than the predetermined distance with respect to the positioning signal of the first signal format of the first satellite has to be determined, the first signal format is used for the data channel. The signal format of the pilot channel can be used without limitation. As a result, it is possible to prevent the number of observations of the positioning pseudorange from being lost or increase the number of observations.

(Embodiment 1)
Hereinafter, the multi-frequency GNSS receiver according to Embodiment 1 of the present invention will be described with reference to FIG. 1 and FIG. The GPS system will be described below, but the present invention can be applied to a plurality of signal formats such as E1, E5, E6 in the GALILEO system.

FIG. 1 is a basic configuration diagram for explaining the baseband processing of the multi-frequency GNSS receiver according to the present invention. The carrier / code synchronization unit 10, the carrier / code synchronization control unit 11, which performs carrier and spreading code synchronization, A replica generation unit 12 that generates a replica of a spread code, a bit synchronization unit 13 that synchronizes bits of a navigation message, a frame synchronization unit 14 that performs frame synchronization of a navigation message, and a pseudo adjustment that is adjusted to obtain a pseudo distance necessary for positioning The distance adjustment unit 15 includes a positioning calculation unit 16 that performs positioning calculation.

A positioning signal input to the carrier / code synchronization unit 10 converts a plurality of positioning signals such as the L1 frequency band, the L2 frequency band, and the L5 frequency band received by an antenna (not shown) into intermediate frequencies, D-converted signal. Each processing unit other than the pseudo distance adjustment unit 15 and the positioning calculation unit 16 may be individually provided for a plurality of positioning signals, or may be switched and used in each frequency band as a common unit.

Carrier synchronization and code synchronization are independently performed by a known method in the carrier / code synchronization unit 10, the carrier / code synchronization control unit 11, and the replica generation unit 12. That is, the positioning signal of the first signal format Si of the first satellite V and the carrier replica and code replica signal generated by the replica generation unit 12 are input to the carrier / code synchronization unit 10, where Carrier correlation and code correlation processing is performed.

The carrier / code synchronization control unit 11 generates a carrier synchronization error and a code synchronization error based on the output of the carrier / code synchronization unit 10, and negatively feeds back the carrier and code synchronization error to the replica generation unit 12.

Normally, carrier synchronization is controlled by a PLL tracking loop, and code synchronization is controlled by a DLL tracking loop. When the code synchronization is completed, the carrier / code synchronization control unit 11 sends a code synchronization completion signal to the bit synchronization unit 13 and sends code phase (correlation peak position) information to the pseudo distance adjustment unit 15.

When the bit synchronization unit 13 receives the code synchronization completion signal from the carrier / code synchronization control unit 11, the bit synchronization unit 13 starts a bit synchronization process synchronized with the bit string signal included in the output of the carrier / code synchronization unit 10. When the bit synchronization is completed, the bit synchronization unit 13 sends a bit synchronization completion signal to the frame synchronization unit 14 and sends bit timing information to the pseudo distance adjustment unit 15.

When the frame synchronization unit 14 receives the bit synchronization completion signal from the bit synchronization unit 13, it starts subframe synchronization processing. When the subframe synchronization is completed, the frame synchronization unit 14 sends the subframe head position information and the HOW word information to the pseudo distance adjustment unit 15. Here, the HOW word information may be deleted.

The pseudo distance adjusting unit 15 calculates and holds a positioning pseudo distance by a known method based on the code phase information, the bit timing information, and at least the subframe head position information. However, although bit synchronization can be achieved, frame positioning cannot be achieved, and thus the positioning pseudorange may not be calculated.

For example, in the positioning signal of the first signal format Si of the first satellite V, if a positioning pseudorange cannot be calculated, a pseudorange less than the bit period (hereinafter referred to as bit synchronization) based on bit timing information and code phase information. Called pseudorange). Then, the bit synchronization pseudo distance is separated into an upper part that is greater than or equal to a predetermined distance and a lower part that is less than the predetermined distance. The lower part less than the predetermined distance and the satellite number and the signal format information related to the calculation of the lower part are held in the pseudo distance adjusting unit 15.

Here, the predetermined distance is a distance corresponding to the minimum spread code period among the positioning signals of a plurality of signal formats to be used. For example, when the signal format to be used includes the L1-C / A signal format, the predetermined distance is the speed of light × 1 msec.

In addition, in the positioning signal of the first signal format Si of the first satellite V, when only code synchronization can be obtained, only a pseudo distance less than a distance corresponding to the spreading code period (hereinafter referred to as a code synchronization pseudo distance) can be obtained. I can't get it. In this case, the pseudo distance adjustment unit 15 obtains the code synchronization pseudo distance as a lower part less than a predetermined distance, and holds it together with the lower part and the satellite number and signal format information relating to the calculation of the lower part.

The pseudorange adjusting unit 15 obtains the pseudo positioning for the second signal format Sj of the first satellite V when the pseudo pseudorange for positioning cannot be obtained with the first signal format Si of the first satellite V. From the distance, an upper part that is a predetermined distance or more is obtained. Then, the sum of the upper part obtained from the second signal format Sj and the lower part obtained from the first signal format Si of the first satellite V is determined by positioning the first satellite V with respect to the first signal format Si. Is sent to the positioning calculation unit 16 as a pseudo-range.

Next, specific processing of the pseudo distance adjustment unit 15 in the first embodiment will be described with reference to the flowchart of FIG.

In step 1, the pseudorange PR (V, Si) of the first signal format Si of the first satellite V used for positioning is obtained. Here, the first signal format Si of the first satellite V is not limited to the data channel, and may be a pilot channel signal format. Here, in the case of the data channel, the bit synchronization or frame synchronization processing of the data channel signal format Si may be intentionally omitted, and only the code synchronization pseudo distance may be obtained.

Thereby, for example, when positioning calculation is performed independently for each of the positioning signals of the frequency format L1 and L2, the bit synchronization and frame synchronization processing of the positioning signal of one signal format can be omitted, and the processing time can be shortened. .

In step 2, the pseudo-range PR (V, Si) of any one of the code-synchronized pseudo-range, bit-synchronized pseudo-range, and positioning pseudo-range is higher than the predetermined distance PR (V, Si) _U and less than the predetermined distance Are separated into the components of the lower part PR (V, Si) _L of and held. Although not shown in FIG. 2, when a lower part less than a predetermined distance cannot be obtained, the following steps jump to the end, and the processing after step 1 is performed for the next satellite.

In step 3, it is determined whether or not the upper part PR (V, Si) _U obtained in step 2 is obtained from the positioning pseudorange. When the upper part PR (V, Si) _U is obtained from the positioning pseudo distance, in step 4, the upper part PR (V, Si) _U + the lower part PR (V, Si) _L is used as the positioning pseudo distance. It is sent to the positioning calculation unit 16. If it is not the upper part due to the positioning pseudorange, in step 5, the pseudorange PR (V, Sj) for the second signal format Sj of the first satellite V is obtained. Here, Sj may be any signal format as long as it is a data channel.

In step 6, it is determined whether or not the pseudo distance PR (V, Sj) is a pseudo distance after frame synchronization, that is, a positioning pseudo distance. If the pseudo distance PR (V, Sj) is a positioning pseudo distance, in step 7, an upper part PR (V, Sj) _U that is a predetermined distance or more from the positioning pseudo distance PR (V, Sj) is obtained. Then, the sum of the pseudorange high order part PR (V, Sj) _U obtained in the signal format Sj and the pseudorange low order part PR (V, Si) _L obtained in the signal format Si is obtained from the first satellite V. It is sent to the positioning calculation unit 16 as a positioning pseudo distance for the first signal format Si.

In step 6, if the pseudorange PR (V, Sj) cannot obtain the positioning pseudorange, the process returns to step 5 to determine the pseudorange for other possible signal formats of the satellite V. If the frame synchronization pseudorange cannot be obtained for any data channel signal format, the adjustment process for obtaining the pseudorange for the satellite V is terminated. The processing from step 1 to step 7 is repeated for at least each of the satellites necessary for positioning.

(Embodiment 2)
Hereinafter, the multi-frequency GNSS receiver according to Embodiment 1 of the present invention will be described. In the first embodiment, when the positioning pseudo-range cannot be obtained by the positioning signal in the first signal format of the first satellite, the positioning signal in the signal format of the second data channel of the first satellite is used. It was a form for obtaining a pseudo distance for positioning.

On the other hand, in the second embodiment, when the positioning pseudo-range cannot be obtained with the positioning signal in the first signal format of the first satellite, the positioning signal in the data channel signal format of any of the second satellites. Is a technique for obtaining a positioning pseudorange for a positioning signal of the first signal type of the first satellite. Note that any data channel signal format of the second satellite can be applied to any data channel signal format of the satellite of the GALILEO system, for example.

The second embodiment is based on the following grounds. In any satellite, the difference in geometric distance between the satellite and the receiver located near the surface of the earth is within 20 msec in terms of time, so that the lower and lower parts of the pseudorange are a predetermined value corresponding to 20 msec. When separated by distance, the upper part is the same distance (distance corresponding to an integral multiple of 20 msec) for any satellite. This means that the pseudorange upper part can be substituted with one obtained from a different satellite signal format.

Since the geometric distance between the receiver and the satellite varies depending on the satellite used for positioning, the predetermined distance in the second embodiment is not limited to a distance corresponding to 20 msec. In principle, the predetermined distance may be determined based on the maximum distance deviation of the geometric distance between each satellite to be used for positioning and the receiver and the usable signal format.

That is, the predetermined distance is a pseudo-range in which the maximum distance deviation of the geometric distance between each satellite used for positioning and the receiver is obtained by code synchronization or bit synchronization of the positioning signal in the first signal format of the first satellite. It may be determined as a distance included. For example, if the maximum distance deviation of the geometric distance between the receiver and each satellite to be subjected to positioning is to 10msec corresponding distance, because this can be obtained from the synchronization pseudoranges NH ₁₀ code L5i, predetermined distance 10msec The equivalent distance may be used.

The specific form of the second embodiment of the present invention is that when only a lower part less than a predetermined distance from the first signal format Si of the first satellite V is obtained, the upper part is any of the second satellites W. It is obtained from the pseudo distance for positioning for the data channel signal format. Also in the second embodiment, the first signal format Si of the first satellite V may be a signal format of a data channel or a pilot channel as long as a pseudo distance less than a predetermined distance can be obtained.

The operation of the pseudo distance adjustment unit 15 in the second embodiment will be described with reference to the flowchart of FIG. The configuration and functions other than the pseudo distance adjustment unit 15 are as described in the first embodiment.

In step 11, the pseudorange adjusting unit 15 obtains the pseudorange of the first signal format Si of the first satellite V. In step 12, the higher-order part PR (V, Si) _U that is equal to or greater than a predetermined distance of the pseudo distance PR (V, Si) of the code synchronization pseudo distance, the bit synchronization pseudo distance, or the frame synchronization pseudo distance is less than the predetermined distance. Are separated into the components of the lower part PR (V, Si) _L of and held. Although not shown in FIG. 3, when a lower part less than a predetermined distance cannot be obtained, the following steps jump to the end, and the processing after step 11 is performed for the next satellite.

In step 13, it is determined whether or not the upper part PR (V, Si) _U obtained in step 12 is the upper part after completion of frame synchronization, that is, obtained from the positioning pseudorange. In the case of the upper part by the positioning pseudo distance, in step 14, the upper part PR (V, Si) _U + the lower part PR (V, Si) _L is transmitted to the positioning calculation unit 16 as the positioning pseudo distance. If it is not the high-order part due to the pseudo distance for positioning, the pseudo distance PR (W, S) for the data channel signal format S of any of the second satellites W is obtained in step 15.

In step 16, it is determined whether or not the pseudo distance PR (W, S) obtained in step 15 is a positioning pseudo distance. If the pseudo distance PR (W, S) is a positioning pseudo distance, in step 17, a higher-order part PR (W, S) _U that is equal to or larger than the positioning pseudo distance PR (W, S) is obtained. Then, the pseudorange lower order part PR (V, Si) _L obtained with the first signal format Si of the first satellite V and the pseudorange upper order part PR (with a signal format S of the satellite W ( The sum of W, S) _U is sent to the positioning calculation unit 16 as a positioning pseudorange for the first signal format Si of the first satellite V.

If the pseudo distance PR (W, S) is not the positioning pseudo distance in step 16, the process returns to step 15 to obtain the pseudo distance for the signal format S of other satellites. Note that the signal format S may be different in the iterative processing of step 15. If the frame synchronization pseudorange cannot be obtained with any signal format S, the adjustment process for obtaining the pseudorange regarding the satellite V is terminated.

The processing from step 11 to step 17 is repeated for at least each satellite having the number of satellites necessary for positioning.

 With the above processing, the positioning signal S in the signal format of the data channel of the second satellite W is obtained with respect to the pseudo distance obtained in the incomplete state with respect to the first signal format Si of the first satellite V. Can be used to obtain a positioning pseudorange for the first satellite V with respect to the first signal format Si.

Configuration block diagram of a multi-frequency GNSS receiver according to Embodiment 1 of the present invention Flowchart for explaining the first embodiment of the present invention Flowchart for explaining the second embodiment of the present invention Explanatory diagram for calculating the transmission time

Explanation of symbols

10 Carrier / code synchronization unit 11 Carrier / code synchronization control unit 12 Replica generation unit 13 Bit synchronization unit 14 Frame synchronization unit 15 Pseudo distance adjustment unit 16 Position calculation unit

Claims (4)

In a multi-frequency GNSS receiver that receives positioning signals of a plurality of signal formats transmitted from the same satellite and outputs at least a position,
A code synchronization unit that performs synchronization processing on a spreading code included in the positioning signals of the plurality of signal formats;
A bit synchronization unit that performs synchronization processing on the bits of the navigation message included in the positioning signal in the signal format;
A frame synchronization unit that performs synchronization processing on the frame of the navigation message;
A pseudo distance adjusting unit that adjusts so as to obtain a positioning pseudo distance based on pseudo distance information obtained from the code synchronizing unit, the bit synchronizing unit, and the frame synchronizing unit;
A positioning calculation unit that performs positioning calculation based on the positioning pseudo distance obtained from the pseudo distance adjustment unit,
The pseudorange adjustment unit, when the pseudorange with respect to the positioning signal of the first signal format of the first satellite is not a pseudorange for positioning obtained from the frame synchronization unit, a subordinate portion less than a predetermined distance from the pseudorange An upper part that is greater than or equal to the predetermined distance is obtained from a pseudo distance for positioning with respect to a positioning signal in the second data channel signal format of the first satellite, and a combination of the upper part and the lower part is obtained. A multi-frequency GNSS receiver characterized by a pseudo-range for positioning with respect to the signal format of The multi-frequency GNSS receiver according to claim 1,
The multi-frequency GNSS receiving apparatus characterized in that the predetermined distance is a distance corresponding to a cycle of the shortest spreading code among positioning signals of a plurality of signal formats to be used. The multi-frequency GNSS receiver according to claim 1 or 2 ,
The multi-frequency GNSS receiver, wherein the first signal format is a positioning signal that does not depend on the presence or absence of a navigation message. In a multi-frequency GNSS receiving method for receiving positioning signals of a plurality of signal formats transmitted from the same satellite and outputting at least a position,
Performing a synchronization process on a spreading code included in the positioning signals of the plurality of signal formats;
Performing a synchronization process on the bits of the navigation message included in the positioning signal in the signal format;
Performing a synchronization process on the frame of the navigation message;
Adjusting to obtain a positioning pseudorange based on the spreading code, the bits of the navigation message, and the pseudorange information obtained by the synchronization processing to the frame of the navigation message;
Performing a positioning calculation based on the pseudo distance for positioning,
If the pseudo distance to the positioning signal of the first signal format of the first satellite is not the pseudo distance for positioning obtained by the synchronization processing to the frame of the navigation message, a lower part less than a predetermined distance is obtained from the pseudo distance. , Obtaining a higher order part of the predetermined distance or more from a pseudo distance for positioning with respect to a positioning signal of the second data channel signal format of the first satellite, and combining the higher order part and the lower order part with the first part. A multi-frequency GNSS receiving method, characterized in that a positioning pseudorange for a signal format is used.

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