TWI596363B - Satellite positioning signal receiving method and device - Google Patents

Description

Satellite positioning signal receiving method and device

The present invention relates to a signal receiving technology received from a satellite positioning signal transmitted by a satellite positioning system represented by a Global Positioning System (GPS), and more particularly, to a signal having two different receiving frequencies. Receiving method and device.

The satellite positioning system is based on the passive determination of satellite positioning signals by a plurality of individual satellite broadcasts. The board timing system is used to generate a regular, continuous series of events, often referred to as "epochs", with random number coding or suspected random number coding at regular intervals. The distance between the spatially generated satellite and the receiving device can be determined by receiving the diffuse-encoded radio wave by the receiving device and measuring the phase difference between the diffusion code generated by the time sequence of the receiving device and the spread code of the received signal.

As an example of such a satellite positioning system, a Global Positioning System (GPS) can be cited. In general, the GPS operates using a plurality of frequencies called L1, L2, and L5 centered at 1575.42 MHz, 1227.6 MHz, and 1176.45 MHz, respectively. The signals are modulated by respective diffusion signals. As can be easily understood by those skilled in the art, a CA (Coarse Acquisition) code signal generated by a GPS satellite navigation system is transmitted at a frequency of 1575.42 MHz (referred to as "L1 band"), and has a frequency of 1.023 MHz. Diffusion coding rate (chip rate). In turn, the signals are superimposed as information of the navigation message, and the data transmission rate is 50 bps. The signal with a diffusion coding rate of 1.023 MHz and a data transfer rate of 50 bps is generally referred to as an "L1 C/A signal". Figure 8 shows L1 Signal structure of the C/A signal.

Further, as an example of the satellite positioning system, a Quasi Zenith Satellite System (QZSS) developed in Japan (Non-Patent Document 1) can be cited. In the same way as the GPS, the QZSS has been developed with the use of a plurality of frequencies such as L1, L2, and L5 centered at 1575.42 MHz, 1227.6 MHz, and 1176.45 MHz. Further, in the QZSS, the E6 frequency centered on 1278.75 MHz is used, and the "LEX signal" is transmitted at this frequency.

In the positioning by the GPS-based satellite positioning system, the ground receiving device receives the radio wave transmitted from the positioning satellite, and measures the distance between the satellite and the receiving device based on the radio wave propagation time from the satellite to the receiving device. Here, for the radio wave transmitted from the self-positioning satellite, the track information indicating the position of the positioning satellite itself, and the clock information indicating the deviation of the satellite's own time are superimposed.

The receiving device can know the position and time of the satellite by demodulating the orbit information and the clock information transmitted from the positioning satellite. Moreover, the receiving device uses the measured value of the distance between the plurality of satellites and the receiving device, the position of the satellite, and the time, and determines the position of the receiving device itself by, for example, the technique of trilateration.

The configuration of a satellite positioning system having a prior satellite positioning signal receiving device is shown in FIG. The receiving device 902 that performs the passive measurement continuously receives the satellite positioning signals from the plurality of positioning satellites 901a to 901d of the satellite positioning system 900, thereby performing positioning and the like. The satellite positioning signal receiving device 902 performs preprocessing on the front end portion 9022 for the signal input from the receiving antenna portion 9021, converts it into a digital signal by an ADC (Analog-to-Digital Converter) portion 9023, and transmits it to the digital signal. Data processing unit 9024.

The block configuration of the data processing unit of the previous receiving device is shown in FIG. The data processing unit 1000 includes one or a plurality of receiving channels (channels 1 to n in the figure), and distributes one satellite positioning signal to each receiving channel for the satellite positioning signals transmitted from the plurality of satellites. Receive processing. The so-called continuous reception processing is aimed at The satellite positioning signal is processed while continuously tracking the information contained in the signal, and the distance measurement (the measurement of the distance between the satellite and the receiving device) is performed in parallel according to the situation.

Here, in order to perform continuous reception processing for each receiving channel, it is necessary to know the frequency of the satellite positioning signal and the phase of the diffusion coding. However, since the frequency of the satellite positioning signal and the phase of the spreading code fluctuate, it cannot be obtained without searching for it at the start of reception.

Further, regarding the frequency of the satellite positioning signal, the frequency is unknown due to the Doppler effect caused by the relative speed of the satellite and the receiving device, or the frequency error of the internal transmitter of the receiving device. In order for each receiving channel to transition to a continuously receivable state, it is necessary to search for the frequency of the satellite positioning signal plus the frequency caused by the Doppler effect (Doppler frequency) or the frequency error of the internal transmitter of the receiving device. frequency.

Further, regarding the diffusion coding, since the satellite positioning signal is spread by repeated diffusion coding, the same diffusion coding sequence is made to have the same phase, and the satellite positioning signal cannot be received unless the correlation with the satellite positioning signal is taken. On the other hand, the coding rate of the diffusion coding is usually in the MHz level, and it is difficult for the circuit board having the receiving device to operate stably with the accuracy for a long period of time. Often, the clock of the satellite transmitting the satellite positioning signal does not coincide with the time. . Therefore, it is almost impossible to know the phase of the diffusion coding beforehand. Therefore, the phase of the diffusion coding must also be searched.

Therefore, in order for the receiving channel to start the reception of one satellite positioning signal, it is necessary to search for the frequency and the phase of the diffusion coding in advance. One of the series of processing of this search is called "capture processing" or "capture". The result of the capture process is the frequency at which the tracking process can be started and the phase of the diffusion coding.

Furthermore, in the capture process, basically all frequencies that may exist for the satellite positioning signal (about ±5 kHz in the case of the L1 C/A signal) and the phase of all the diffusion codes (in the case of the L1 C/A signal) Search for 1023 wafers). The frequency interval for searching is determined according to the characteristics of the satellite positioning signal. In the case of the L1 C/A signal, it is set. About 500 Hz is more common. Also, the phase of the diffusion coding of the search must search for the number of wafers only for diffusion coding. That is, if the length of the diffusion code and the number of wafers increase, the amount of calculation processing required for the entire capture processing increases.

If the receiving channel can obtain the frequency for starting tracking by the capture and the phase of the diffusion coding, then the frequency of the satellite positioning signal and the phase of the diffusion coding are updated while maintaining the reception state. Specifically, a conventional tracking circuit 1100 as illustrated in FIG. 11 is used, based on the continuously received satellite positioning signals, and each of the phases of the frequency and the diffusion coding is controlled by the following synchronization circuit, and the reception state is maintained. .

First, regarding the frequency, it is more common to use a phase lock circuit (PLL) 1101. The PLL is a processing circuit that takes a periodic signal as an input and performs stable signal reception processing by feedback control. In the satellite positioning receiving device, the captured frequency is used as an initial value, and the sequentially updated frequency f _L1 can be obtained as an output with respect to the input satellite positioning signal.

Secondly, regarding the phase of the diffusion coding, it is more common to use a Delay Lock Loop (DLL) 1104. Similarly to the PLL, the DLL is a processing circuit that takes a periodic signal as an input and performs stable signal reception processing by feedback control. In the satellite positioning signal receiving apparatus, the phase of the diffusion coded by the capture is used as an initial value, and the phase Φ _{L1 of} the sequentially updated diffusion code is obtained as an output with respect to the input positioning signal.

As described above, using the received satellite positioning signal as an input, using the frequency and the phase of the diffusion coding, and performing a series of processing by the respective synchronization circuits is referred to as "tracking processing" or "tracking". The tracking process is based on a specific period based on the characteristics of the satellite positioning signal, and the updated frequency and the phase of the spreading code can be obtained for each tracking process. Also, the self-tracking circuit obtains the information contained in the satellite positioning signal as an output.

Then, in the receiving channel for tracking, the satellite positioning signal can be interpreted. Contains the message. The interpretation of the message is carried out in the "Interpretation Department". Further, in the receiving channel for tracking, the distance between the satellite and the receiving device can be measured. This is called "ranging" and is performed in the "ranging unit". The principle of ranging is to read the propagation time from the time difference of the diffusion coding of the phase (which is generated on the receiving device side) by the spreading code transmitted at the known time on the satellite side, and by multiplying it by the time difference The configuration of the distance is measured at the speed of light. Specifically, it is as follows.

The time to locate the satellite is managed by a sophisticated satellite clock, and the timing of the transmitted spreading code is correctly followed by the satellite clock. On the other hand, if the satellite positioning signal receiving device tracks the satellite positioning signal and performs message interpretation, the correct time of transmitting the signal can be known. . Moreover, the satellite positioning signal receiving device generates the same diffusion code as the positioning satellite with a consistent phase during the tracking of the satellite positioning signals from the positioning satellites. Since the satellite positioning signal repeats the diffusion coding at a certain period (for example, 1 ms in the case of the L1 C/A signal), the phase of the diffusion coding synchronized with the satellite positioning signal The value refers to the transmission time of the signal T _u at the instant of reception at a finer accuracy than 1 ms (in the case of the L1 C/A signal).

Therefore, the satellite positioning signal receiving device is based on the time when the satellite positioning signal is transmitted from the satellite. Phase with diffusion coding Based on this, the propagation time from the self-positioning satellite to the satellite positioning signal receiving device can be known. In fact, the accuracy of the board clock in the receiving device is not as good as the clock of the positioning satellite. That is, the difference between the positioning satellite and the satellite positioning signal receiving device becomes the propagation time on the surface containing the error. However, since the propagation time is measured with the same error for all positioning satellites, it will not be a big problem (will be described below). Therefore, the distance measured on the receiving device side is often referred to as a "suspected distance." The calculation procedure for the suspected distance is shown in FIG.

Fig. 12 is a flow chart showing an example of a calculation procedure based on the previous suspected distance of the L1 C/A signal. The meaning of each variable of Fig. 12 is as follows.

: phase of the diffusion code of the positioning satellites of the k receiving channels [(0~1023) wafer]

: sending time of positioning satellites of k receiving channels [sec]

T _u : reception time of the satellite positioning signal receiving device [sec]

C: speed of light ≒ 3 × 10 ⁸ [m / sec]

d ^k : suspected distance [m]

In Fig. 12, the calculation of the suspected distance starts from the state in which the satellite positioning signal is first tracked as the kth receiving channel of the object (S1201).

Although it is the phase of the diffusion coding of the satellites of the k receiving channels, since it can obtain the updated frequency and the phase of the diffusion coding by tracking, the phase of the diffusion coding directly obtained by the tracking is set. (S1202). Furthermore, in the case of the L1 C/A signal, the phase of the diffusion coding takes a value of 0 or more and less than 1023.

Second, I don’t know In the case (No in S1203) However, if the message has been interpreted, the time of the signal transmitted by the satellite can be calculated from the time information contained in the message (S1204). For example, in the case of the message of the L1 C/A signal, it includes time information expressed in seconds per second for every 6 seconds. Here, the content of the transmission start time of the signal included in the message is recorded in the message. Therefore, as long as the message containing the time information is interpreted once, the time of the continuous reception of the L1 C/A signal from the satellite can be known, and can be updated in sequence thereafter. Set this time to .

Next, as knowledge Who (S1203, YES) and the calculated T _u, but not for the first of the track, when the case has been set for the T _u (S1205, Yes), enter the S1207, but in the case of the initial track of (S1205 NO Then, the process proceeds to S1206, based on the initially tracked receiving channel, and the clock T _{u in the} receiving device is set to an appropriate value. For example, if the method of setting the initially tracked receiving channel is k receiving channels, the setting of T _u can be The value obtained by adding an appropriate value (for example, 100 ms) is followed by the clock in the receiving device operating as a reference. Furthermore, since the appropriate value used herein is equivalent to the amount of error common to each of the satellites and the suspected distance in the receiving device, it can be substantially any value.

As described above, if , And T _u is based on the speed of light C, and the suspected distance d ^{k of the} L1 C/A signal can be calculated by the following equation (S1207).

As described above, the position of the receiving device can be calculated by the "positioning calculation unit" based on the result of the measurement (suspected distance) obtained in each receiving channel. This is a summary of the "location" process. For positioning, satellite positioning signals from more than four positioning satellites are required. By obtaining a suspected distance from the minimum of four positioning satellites, the amount of error caused by the "appropriate value" used in setting the clock in the receiving device can be eliminated.

[Previous Technical Literature]

[Non-patent literature]

[Non-Patent Document 1] Aerospace Research and Development Agency: "Quasi-Zenith Satellite System User Interface Specification (IS-QZSS) Version 1.1", July 31, 2009, Internet <URL: http://qzss.jaxa .jp/is-qzss/>

The satellite positioning signal broadcast by the satellite positioning system is not aimed at the ranging itself, but there is a signal having the function of correcting/reinforcing the distance between the satellite obtained by the ranging and the receiving device, or the function of the positioning position of the receiving device. This is called "reinforcing signal", and the information contained in the reinforcing signal is called "reinforcing information". It is more common for the reinforcement information in the reinforcement signal to be included in the message part.

In order to interpret the reinforcement information by the ordinary method, the receiving device must assign a receiving channel to the reinforcing signal in the same manner as the method for the ranging signal, and perform the capturing processing and tracking processing of the frequency band, and the interpretation processing. .

However, the spreading code of the frequency band or the reinforcing signal broadcasted by the reinforcing signal is often different from the frequency band or diffusion coding of the signal used for the general ranging. Used to handle only ranging The receiving device that processes the reinforcing signal requires a larger processing power or resource than the processing capability or resources of the receiving device of the signal. Moreover, in the case of the LEX signal, it is more special. In order to perform the interpretation of the message including the reinforcing signal contained in the short code of the LEX signal, first, it must be received by 2.5575 MCps. The signal of 410ms long long code is diffused. It is much longer than 1.023 MHz of the L1 C/A signal used in normal ranging. The 1ms long diffusion code is used to spread the signal. Therefore, if the receiving apparatus that has assumed that the processing of L1 C/A is to perform the capture processing and the tracking processing of the LEX signal, there is an increase in parts or processing, resulting in a large increase in cost.

The present invention is characterized in that it is a satellite positioning signal receiving device including a satellite positioning system that transmits one or more positioning satellites having different first and second signals having different frequencies, and the satellite positioning signal receiving device is based on starting or continuing the above. The frequency and phase information obtained at the time of reception of the first signal is converted into the frequency and phase information of the second signal.

Further, the message information included in the second signal is interpreted based on the converted frequency and phase information of the second signal.

Further, tracking of the second signal is continued based on the frequency and phase information of the converted second signal.

Further, a distance between the positioning satellite and the satellite positioning signal receiving device is measured based on frequency and phase information of the first signal or frequency and phase information of the converted second signal.

Furthermore, the present invention is characterized in that it is a satellite positioning signal receiving method in a satellite positioning system including a positioning satellite and a satellite positioning signal receiving device that transmit a first signal and a second signal having different frequencies, and the satellite positioning signal receiving device is The frequency and phase information obtained when the reception of the first signal is started or continued is converted into the frequency and phase information of the second signal.

According to the satellite positioning signal receiving method and apparatus of the present invention, it is possible to provide a method for reducing the amount of arithmetic processing and reducing the cost required for processing the processing parts in the capturing processing and tracking processing of satellite positioning signals of two different frequencies. .

100‧‧‧Satellite Positioning System

101a‧‧‧ Positioning satellite

101b‧‧‧ Positioning Satellite

101c‧‧‧ positioning satellite

101d‧‧‧Targeting satellite

102‧‧‧Satellite positioning signal receiving device

1021‧‧‧ Receiving antenna unit

1022‧‧‧ front end

1023a‧‧‧Department of ADC

1023b‧‧‧Department of ADC

1024‧‧‧ Data Processing Department

200‧‧‧ Data Processing Department

201‧‧‧L1 Capture Department

202‧‧‧L1 Tracking Department

203‧‧‧L1 Interpretation Department

204‧‧‧L1-E6 Conversion Processing Department

205‧‧‧E6 Interpretation Department

501a‧‧‧Satellite

502‧‧‧Satellite positioning signal receiving device

5021‧‧‧ receiving antenna

5022‧‧‧ front end

5023a‧‧‧Department of ADC

5023b‧‧‧Department of ADC

5024‧‧‧ Data Processing Department

5025‧‧‧E6 Interpretation Department

600‧‧‧Data Processing Department

601‧‧‧L1 Capture Department

602‧‧‧L1 Tracking Department

603‧‧‧L1 Interpretation Department

604‧‧‧L1-E6 Conversion Processing Department

700‧‧‧Signal generation circuit

701‧‧‧Diffusion code generator

702‧‧‧CSK modulator

703‧‧‧Rectangular wave

705‧‧‧ Carrier (1278.75MHz)

900‧‧‧Satellite Positioning System

901a‧‧‧ positioning satellite

901b‧‧‧ positioning satellite

901c‧‧‧ positioning satellite

901d‧‧‧ positioning satellite

902‧‧‧Satellite positioning signal receiving device

9021‧‧‧ Receiving antenna unit

9022‧‧‧ front end

9023‧‧‧Department of ADC

9024‧‧‧ Data Processing Department

1000‧‧‧Data Processing Department

1001-1‧‧‧Capture Department

1001-2‧‧‧ Tracking Department

1001-3‧‧‧Interpretation Department

1001-4‧‧‧Ranging Department

1002‧‧‧ Positioning Operations Department

1100‧‧‧ Tracking circuit

1101‧‧‧ Phase Synchronization Circuit (PLL)

1102‧‧‧Sine wave generator

1103‧‧‧Diffusion code generator

1104‧‧‧Delayed Synchronization Circuit (DLL)

Fig. 1 is an explanatory view showing a schematic configuration of a satellite positioning system having a satellite positioning signal receiving apparatus according to an embodiment of the present invention.

Fig. 2 is an explanatory view showing a block configuration of a satellite positioning signal receiving apparatus according to an embodiment of the present invention.

Fig. 3 is a flow chart showing the flow of processing of the satellite positioning signal receiving apparatus according to an embodiment of the present invention.

Fig. 4 is an explanatory view showing the relationship between the L1 C/A signal and the LEX signal of the satellite positioning system according to an embodiment of the present invention.

Fig. 5 is an explanatory view showing a schematic configuration of a satellite positioning system having a satellite positioning signal receiving apparatus according to another embodiment of the present invention.

Fig. 6 is an explanatory view showing a block configuration of a satellite positioning signal receiving apparatus according to another embodiment of the present invention.

Fig. 7 is an explanatory view showing a signal generating circuit of a satellite positioning system according to an embodiment of the present invention.

Fig. 8 is an explanatory diagram showing the signal structure of the previous L1 C/A signal.

Fig. 9 is an explanatory view showing the configuration of a satellite positioning system having a satellite receiving signal receiving apparatus of the prior art.

Fig. 10 is an explanatory view showing a block configuration of a data processing unit of the prior receiving apparatus.

Figure 11 is an explanatory view showing the block configuration of the previous tracking circuit.

Figure 12 is a flow chart illustrating the calculation procedure of the previous suspected distance.

Hereinafter, the form of the satellite positioning signal receiving method and apparatus for carrying out the present invention will be described in detail with reference to the drawings.

[Example 1]

Fig. 1 shows a schematic configuration of a satellite positioning system having a satellite positioning signal receiving apparatus according to an embodiment of the present invention. In an embodiment of the present invention, it is set to process the LEX signal, and the QZSS (quasi-zenith satellite system) that transmits the LEX signal is used as a model of the satellite positioning system.

In FIG. 1, the L1 C/A signal and the LEX signal respectively broadcasted from the positioning satellites 101a to 101d of the QZSS system 100 are transmitted in outer space and the atmosphere, and reach the satellite positioning signal receiving device 102. The L1 C/A signal and the LEX signal that have arrived at the receiving device 102 are converted to a frequency (intermediate frequency) (referred to as "frequency conversion" or "down conversion") at the front end portion 1022 to facilitate the processing of the respective carrier frequencies. The intermediate frequency differs depending on the design concept of the receiving device. In the present specification, for convenience of explanation, the intermediate frequency of the L1 C/A signal is set to f _IFL1 , and the intermediate frequency of the LEX signal is set to f _IFE6 . Each of the down-converted signals is quantized in the ADC units 1023a and 1023b, and transmitted to the data processing unit 1024 for reception processing.

Next, the detailed configuration of the data processing unit 1024 of Fig. 1 is shown in Fig. 2 .

In FIG. 2, in general, since the positioning receiving device receives signals from a plurality of positioning satellites, there are a plurality of receiving channels in the data processing unit, but in the present specification, in order to facilitate understanding and explanation of the invention, only 1 Description of the action of the receiving channel. Further, illustratively, it will be described as an embodiment of a message for interpreting an LEX signal.

In FIG. 2, the data processing unit 200 illustratively includes an L1 capture unit 201 that performs L1 C/A signal capture processing, an L1 trace unit 202 that performs L1 C/A signal tracking, and an L1 interpretation unit 203. Interpreting the L1 C/A signal; the L1-E6 conversion processing unit 204 performs the phase from the L1 C/A signal and the phase of the diffusion coding to the LEX signal. Conversion processing of frequency and phase of diffusion coding; and E6 interpretation unit 205, which performs interpretation of the LEX signal.

Furthermore, in the case of a satellite positioning signal receiving device of a plurality of receiving channels, the components are included as constituent elements of one receiving channel, and may be used in each channel depending on the situation. The distance portion is combined with one "positioning calculation unit". In this case, the "ranging unit" and the "positioning unit" can be configured in common with the data processing unit of the ordinary receiving device.

The processing flow of the data processing unit 200 is shown in FIG.

In the data processing unit 200, first, processing is started in S301, and after the initial value f _L1 of the frequency of the satellite positioning signal and the initial value Φ _L1 of the phase of the diffusion encoding are acquired in S302, the capture of the L1 C/A signal is performed. Processing (S303). The capture processing performs a correlation calculation with the input satellite positioning signal based on the acquired f _L1 and Φ _L1 to determine whether the capture succeeds or not based on the magnitude of the correlation value (S304). As long as the acquisition of f _L1 and Φ _L1 used in the tracking is unsuccessful (NO in S304), the process returns to S303 for supplementary processing. During the supplementary processing, slowly change f _L1 and Φ _L1 to set the frequency of the time points of f _L1 and Φ _L1 and the phase of the diffusion coding when the highest correlation value is obtained, as the frequency used in the subsequent tracking. And an initial value of the phase of the diffusion coding (S305).

Furthermore, the method of slowly changing f _L1 and Φ _L1 or the criterion for determining the success or failure of capture can be used, and the algorithm used in the capture can use the capture algorithm previously used. As a result of the capture process, the frequency f _{L1 for} tracking the L1 C/A signal and the phase Φ _{L1 of the} diffusion coding are obtained.

Further, when the frequency of the first use in the tracking and the phase of the diffusion coding are determined by the capture of the L1 C/A signal, the capture is completed, and then the tracking of the L1 C/A signal is performed (S305). The f _L1 obtained by the capture first is set as the frequency of the satellite positioning signal, and Φ _{L1 is} set as the phase of the diffusion coding of the satellite positioning signal, thereby performing tracking processing.

The algorithms used in the tracking can use the known tracking algorithms previously used. By using the L1 C/A signal as an input tracking process, the frequency and the phase of the diffusion coding can be sequentially updated to become new f _L1 and Φ _L1 .

Furthermore, specifically, the frequency at which the signal is tracked is obtained by adding the Doppler frequency to the intermediate frequency. The Doppler frequency is determined based on the relative speed of the positioning satellite and the satellite positioning signal receiving device, and the frequency of transmission. That is, since the frequency transmitted in the L1 C/A signal and the LEX signal is different even if transmitted from the same positioning satellite, the Doppler frequency also becomes a different value.

Further, in the tracking processing of the L1 C/A signal, as long as no abnormality occurs in the receiving state (YES in S306), that is, as the correct receiving state, the tracking processing is continued (S306). When the tracking processing of the L1 C/A signal is not correctly continued for some reason (NO in S306), the capture processing is returned (S303), and after the capture processing is completed, the re-tracking processing is repeated.

During the tracking process of the L1 C/A signal, the interpretation of the L1 C/A signal is performed in the interpretation unit (S307).

Next, while the tracking of the L1 C/A signal continues, as long as the time information is acquired (S309), the L1-E6 conversion process can be performed based on the time information and f _L1 and Φ _L1 (S308) (S310). Furthermore, it is sufficient to obtain time information once during the duration of the tracking.

In the L1-E6 conversion process, the following two processes are performed.

(Process A) Conversion from the frequency of the L1 C/A signal to the frequency of the LEX signal

(Process B) Conversion processing from the phase of the diffusion coding of the L1 C/A signal to the phase of the diffusion coding of the LEX signal

Furthermore, the present invention is characterized in that the above description "diffusion coding of the LEX signal" means that the message of the LEX signal is modulated by a CSK (code shift keying) 4 ms period, which is not as before. Technology-based reception of long codes.

Conversion from the frequency of the L1 C/A signal to the frequency of the LEX signal (process A above) It is carried out in the following formula (2).

Where f _E6 : the frequency of the LEX signal [Hz]

f _L1 : frequency of L1 C/A signal [Hz]

f _IFE6 : intermediate frequency of the LEX signal [Hz]

f _IFL1 : intermediate frequency of L1 C/A signal [Hz]

E ₆ : center frequency of LEX signal ≡1278750000 [Hz]

L ₁ : center frequency of L1 C/A signal ≡1575420000[Hz]

The above equation (2) indicates that the frequency of the LEX signal f _E6 can use the frequency of the L1 C/A signal f _L1 , the intermediate frequency of the L1 C/A signal f _IFL1 , the intermediate frequency of the LEX signal f _IFE6 , the center of the L1 C/A signal The frequency L ₁ and the center frequency E _{6 of the} LEX signal are calculated.

Here, L ₁ is a known value (1575.42 MHz), and E ₆ is a known value (1278.75 MHz). f _IFL1 and f _IFE6 can use inherently known values depending on the design of the receiving device.

Since f _L1 is the frequency of the L1 C/A signal, the frequency f _L1 used in the tracking can be directly used.

As described above, the conversion process from the frequency of the L1 C/A signal to the frequency of the LEX signal is performed based on the above formula (2).

Further, the phase conversion from the phase of the diffusion coding of the L1 C/A signal to the phase of the diffusion coding of the LEX signal (the above-described process B) is performed based on the following equation (3).

Where k is the value of any of 0, 1, 2, 3, φ _E6 : the phase of the diffusion frequency of the LEX signal [wafer]

φ _L1 : phase of diffusion coding of L1 C/A signal [wafer]

R _L1 : diffusion coded chip rate of L1 C/A signal ≡10230000[Cps]

T _L1 : diffusion coding period of L1 C/A signal ≡0.001 [sec]

R _E6 : Diffusion coded chip rate of LEX signal ≡ 2557500 [Cps]

The above (3) indicates that the phase Φ _E6 of the diffusion coding of the LEX signal can use the phase Φ _L1 of the diffusion coding of the L1 C/A signal, the chip rate of the L1 C/A signal, and the chip rate R _L1 , L1 C/A signal. diffusion encoded period T _L1, and diffusion LEX signals encoded chip rate R _E6 calculated.

Here, R _L1 is a known value (1.023 MCps), and further, T _L1 is a known value (0.001 sec), and R _E6 is a known value (2.5575 MCps). Since Φ _L1 is the phase of the diffusion coding of the L1 C/A signal, the phase Φ _L1 of the diffusion coding used in the tracking can be directly used.

Furthermore, k is a value that varies according to the diffusion coding period of the two signals. In the case of L1 C/A and LEX, it is an integer using the value of [0, 3]. That is, 0, 1, 2, 3, 0, 1, 2, 3, 0, ..., k are updated every 1 ms. The value of k is determined by the time information obtained by the interpretation of the L1 C/A signal. Specifically, the relationship between the L1 C/A signal and the LEX signal shown in FIG. 4 will be described with reference to the drawings.

In Fig. 4, the time at which the currently received satellite positioning signal is transmitted is set to t _x [sec]. t _x can be used in the tracking processing of the L1 C/A signal, by message interpretation, in a ratio of 6 seconds, and based on the time information contained in the message, and the number of times of self-diffusion coding repetition and tracking The phase Φ _L1 of the diffusion coding of the L1 C/A signal is obtained.

Next, the time at which the diffusion coding of the L1 C/A signal and the diffusion coding of the LEX signal start simultaneously are defined as t ₀ [sec]. The L1 C/A signal and the LEX signal are based on the start of the week and start the transmission of the signal. Since the diffusion coding period T _E6 of the LEX signal is 4 ms, the diffusion coding period T _L1 of the L1 C/A signal is 1 ms, so after the start of the week, the diffusion coding of the L1 C/A signal and the diffusion coding of the LEX signal are correctly performed. 4ms starts at the same time. That is, based on the start of the week, the diffusion coding of the L1 C/A signal and the diffusion coding of the LEX signal must start simultaneously at a multiple of 4 ms. In FIG. 4, when viewed t _x nearest previously, the back diffusion within the L1 C / A coded signals to 4 cycles, there must diffusion diffusion encoding L1 C / A coded signals simultaneously with the start of the signal LEX time. That is, before t _x , the most recent time which is a multiple of 4 ms is t ₀ .

The value of k represented by the above formula (3) is the number of periods of diffusion coding of the L1 C/A signal included between t _x and t ₀ . That is, the time from the start of the diffusion coding of the L1 C/A signal and the diffusion coding of the LEX signal is used as a reference, and is updated every 1 ms from k=0.

As described above, the phase transition from the phase of the diffusion coding of the L1 C/A signal to the diffusion coding of the LEX signal is performed.

When the L1-E6 conversion processing is completed in S310, the process proceeds to S311, and the LEX message interpretation is performed.

Referring again to Figure 2. The frequency of the LEX signal and the phase of the diffusion coding calculated by the L1-E6 conversion processing unit 204 are transmitted to the E6 interpretation unit 205, and the E6 interpretation unit 205 is used to interpret the message included in the LEX signal.

In FIG. 2, the flow of the signal from the L1 tracking unit 202 through the L1-E6 conversion processing unit 204 to the E6 interpretation unit 205 is indicated by a broken line, meaning that the inter-block passer is not input to the data processing. The satellite positioning signal is the phase of the frequency and diffusion code calculated based on the data, and the time information based on the message interpreted in the interpretation section.

The E6 interpretation unit 205 interprets the information contained in the signal based on the frequency of the converted LEX signal and the phase of the diffusion coding. When actually interpreting the message of the LEX signal, it is necessary to know the start time of the LEX diffusion coding every 4 ms, but it is equivalent to the diffusion coding simultaneous start time used when the L1-E6 conversion processing section 204 calculates the phase of the diffusion coding of the LEX signal. t ₀ . t ₀ can use the phase Φ _E6 of the diffusion coding of the converted LEX signal, which is expressed by the following equation.

That is, the start time of the LEX diffusion coding (= diffusion coding simultaneous start time) t ₀ can use the transmission time t _x of the signal currently being received, the phase Φ _E6 of the diffusion coding of the converted LEX signal, and the diffusion coding of the LEX signal. The chip rate R _E6 is calculated.

As a result, the message interpretation of the LEX signal can remove the frequency component superimposed on the LEX signal based on the frequency of the converted LEX signal from the frequency of the converted LEX signal from t ₀ and decode the CSK modulated short code. Interpret the message of the LEX signal.

As explained above, the information contained in the LEX signal can be directly interpreted based on the frequency of the converted LEX signal and the phase of the spreading code.

Moreover, as a more advanced process, based on the frequency of the converted LEX signal and the phase of the spread coding, a 1 receive channel can be re-assigned to the LEX signal, thereby starting the tracking of the long code of the LEX signal. In this case, there is an advantage that the capture processing by the long code of the LEX signal required to start the long code tracking of the LEX signal by the conventional prior art can be omitted.

In this case, while continuing the tracking process of the long code of the LEX signal, the message contained in the short code of the LEX signal is interpreted.

One of the features of the present invention resides in the aspect of omitting the capture processing/tracking processing of the LEX signal, and interpreting the LDX signal from the frequency obtained by the capture processing/tracking processing of the L1 C/A signal and the phase of the diffusion coding. Reinforce information. Although the frequency of transmission is different, in order to transmit the L1 C/A signal and the LEX signal from the same satellite, it is possible to periodically transmit the spread codes of the two signals at the same timing.

In the best mode for carrying out the invention as described above, it is preferred to continuously receive the L1 C/A signal, and determine the frequency of the LEX signal and the phase of the diffusion coding from the phase of the frequency and the diffusion coding, and since then Interpret the reinforcement information contained in the LEX signal.

[Embodiment 2]

In the embodiment described above, the configuration in which the E6 interpretation unit is provided in the data processing unit has been described. However, the present invention is not limited thereto. For example, as shown in FIG. 5, it may be configured. The E6 interpretation unit 5025 is provided as another system of the data processing unit 5024. That is, it is considered that the frequency of the LEX signal and the phase of the diffusion coding are transmitted to the E6 interpretation unit 5025 located in another system as the output of the data processing unit 5024. In this case, the satellite positioning signal output from the ADC unit 5023b, the frequency of the converted LEX signal, and the phase of the diffusion coding are output as a receiving device, and are transmitted to the E6 interpretation unit (dedicated device) 5025 in another route.

In this case, as shown in the data processing unit 600 of FIG. 6 as an example block diagram of the data processing unit 5024, the data processing unit 600 can input the L1 C/A signal. There is no need to input the E6 signal.

[Example 3]

Further, in the above description, the L1 C/A signal and the LEX signal are treated as two different signals, but the present invention is not limited to the combination of the L1 C/A signal and the LEX signal, as long as it is transmitted from the same positioning satellite 2 Satellite positioning signals of different frequencies can be similarly based on satellite positioning signals for processing processing requiring relatively low processing requirements for tracking processing/tracking processing, and obtaining satellite positioning signals with relatively high processing power for capturing processing/tracking processing requirements. News.

[Example 4]

Moreover, by transmitting the difference between the L1 band of the L1 C/A signal and the frequency of the E6 band carrying the LEX signal, when two signals are transmitted in outer space and in the atmosphere, they are affected by the ionosphere existing in the air on the earth. In other words, a difference is generated between the signals of the two frequencies at the propagation distance (this is called "ionospheric delay error"). Since the ionospheric delay error also affects the phase of the diffusion coding of the L1 C/A signal and the phase of the diffusion coding of the LEX signal, the phase of the diffusion coding from the L1 C/A signal to the phase of the diffusion coding of the LEX signal is performed. In the case of conversion, it is further preferred to consider the ionospheric delay error generated between the two frequencies.

As an example, the difference caused by the ionospheric delay error can be predicted according to an academic model such as the Klobuchar model. Therefore, in this case, the phase conversion from the phase of the diffusion coding of the L1 C/A signal to the phase of the diffusion coding of the LEX signal shown in the above equation (3) includes the L1 C/A signal indicating the delay error caused by the ionosphere. The term ψ _K of the phase difference between the diffusion coding and the diffusion coding of the LEX signal can be expressed as follows.

Where ψ _K : the phase difference between the diffusion coding of the L1 C/A signal caused by the ionospheric delay error and the diffusion coding of the LEX signal

[Example 5]

Further, in the above embodiment, the L1 C/A signal and the LEX signal are input to the receiving device, and are respectively input to the data processing unit via ADC conversion in the ADC unit, but the difference between the respective electrical paths is equal. The effect is that the phase of the diffusion coding of the L1 C/A signal and the phase of the diffusion coding of the LEX signal cause an error amount.

Therefore, when converting the phase of the diffusion coding from the L1 C/A signal to the phase of the diffusion coding of the LEX signal, it is preferable to consider the amount of error generated between the two frequencies.

In this case, a plurality of values which become the amount of error are predicted, and conversion is performed by taking each of them into consideration, so that a plurality of results can be obtained. As a specific processing procedure, the phase conversion from the phase of the diffusion coding of the L1 C/A signal to the phase of the diffusion coding of the LEX signal shown in the above equation (3) includes the diffusion of the L1 C/A signal caused by the error amount. The term ψ _n of the phase difference between the code and the diffusion code of the LEX signal can be improved as described in the following equation.

Where ψ _n : is expected to be the phase difference between the diffusion coding of the nth L1 C/A signal and the diffusion coding of the LEX signal

Furthermore, in order to predict a number of values that become the amount of error, and to consider each In the case of the conversion, the error amount may include the difference between the phase of the diffusion coding of the L1 C/A signal and the phase of the diffusion coding of the LEX signal in consideration of the ionospheric delay error.

[Embodiment 6]

Finally, an example of a signal generating circuit of a satellite positioning system according to an embodiment of the present invention will be described in advance. Fig. 7 shows a circuit for generating an LEX signal used in a satellite positioning system according to an embodiment of the present invention.

As an example, the signal generation circuit 700 is related to the LEX signal broadcasted in the 1278.75 MHz band (E6 band) of the Quasi-Zenith Satellite System (QZSS), but the LEX signal is utilized as a reinforcing signal.

The LEX signal is alternately selected by the diffusion code generator 701 at intervals of 5.115 Mcps, and is modulated by the CSK code by the CSK modulator 702 by 4 ms (= 256) messages of 4 ms length. The diffusion code of 2.5575 Mcps of the code, and the diffusion code generated by the diffusion code generator 701, which is superimposed on the rectangular wave generated by the rectangular wave generator 703, is 410 ms long and 2.5575 Mcps is called "long code". The clock control is performed and superimposed and transmitted on the carrier frequency of 1278.75 MHz generated in the carrier generator 705.

Furthermore, the so-called CSK modulation system is an abbreviation for code shift keying, and one of the modulation methods of the phase change of the diffusion coding by the value of the data.

[Know-known technology, etc.]

The contents of all the papers and documents that are related to the present invention, which are applied at the same time as the present specification or which are applied in advance to the present specification, and which are freely available to the public, are incorporated herein by reference.

[combination]

All of the constituent elements and/or all of the disclosed methods or processes described in this specification (including claims, embodiments, abstracts, and drawings) may be removed. The features are mutually exclusive combinations and are combined in any combination.

[A characteristic example]

Each of the features described in the specification (including the claims, the embodiments, the abstract, and the drawings) may be replaced with the features for the same purpose, equivalent purpose, or the like. Therefore, as long as it is not explicitly denied, each of the features disclosed is only one example of the feature that the one series is the same or equal.

The present invention is not limited to any specific configuration of the above embodiment. The invention may be extended to all novel features or combinations thereof, or all novel methods or process steps, or combinations thereof, as described in the specification (including the claims, the examples, the abstract, and the drawings).

100‧‧‧Satellite Positioning System

101a‧‧‧ Positioning satellite

101b‧‧‧ Positioning Satellite

101c‧‧‧ positioning satellite

101d‧‧‧Targeting satellite

102‧‧‧Satellite positioning signal receiving device

1021‧‧‧ Receiving antenna unit

1022‧‧‧ front end

1023a‧‧‧Department of ADC

1023b‧‧‧Department of ADC

1024‧‧‧ Data Processing Department

Claims (10)

A satellite positioning signal receiving device, comprising: a satellite positioning signal receiving device for a satellite positioning system that transmits one or more positioning satellites having different first and second signals of different frequencies, and wherein the satellite positioning signal receiving device is : based on the frequency and phase information obtained when the first signal is received or continued, the conversion process is the frequency and phase information of the second signal, and based on the frequency and phase information of the converted second signal, The message information included in the second signal; wherein the interpretation of the message information is performed independently of tracking of the second signal based on the frequency and phase information of the converted second signal. The satellite positioning signal receiving device of claim 1, wherein the positioning satellite and the satellite positioning signal receiving device are determined based on the frequency and phase information of the first signal or the converted frequency and phase information of the second signal The distance. A satellite positioning signal receiving apparatus according to claim 1 or 2, wherein said first signal is a C/A signal of an L1 frequency band (1575.42 MHz band). A satellite positioning signal receiving apparatus according to claim 1 or 2, wherein said second signal is a TEX signal of an E6 frequency band (1278.75 MHz band). The satellite positioning signal receiving apparatus according to claim 1 or 2, wherein the frequency and phase information conversion processing of the second signal is performed based on a difference between a frequency of the first signal and a frequency of the second signal The ionospheric delay error component is subjected to the above conversion processing. The satellite positioning signal receiving apparatus according to claim 1 or 2, wherein the phase information of the first signal and the phase information of the second signal are included in the conversion processing of the frequency and phase information of the second signal The error is set to a plurality of candidates for the phase information of the second signal, and the conversion processing is performed. A satellite positioning signal receiving method, which is characterized in that it comprises a satellite positioning signal receiving method in a satellite positioning system of a positioning satellite and a satellite positioning signal receiving device that transmit a first signal and a second signal having different frequencies, and the satellite positioning is performed. The signal receiving device converts the frequency and phase information obtained from the reception of the first signal to the frequency and phase information of the second signal, and based on the frequency and phase of the converted second signal Information for interpreting the message information contained in the second signal; wherein the interpretation of the message information is performed independently of tracking of the second signal based on the frequency and phase information of the converted second signal. The satellite positioning signal receiving method of claim 7, wherein the positioning satellite and the satellite positioning signal receiving device are determined based on the frequency and phase information of the first signal or the converted frequency and phase information of the second signal. The distance. The satellite positioning signal receiving method of claim 7 or 8, wherein the first signal is a C/A signal of an L1 frequency band (1575.42 MHz band). The satellite positioning signal receiving method of claim 7 or 8, wherein the second signal is an LEX signal of an E6 frequency band (1278.75 MHz band).