Signal tracking method and device, computer storage medium and terminal

Abstract

According to the signal tracking method and device, the computer storage medium and the terminal, first tracking related information of a non-CSK modulation signal of a first frequency point is captured and tracked, and second tracking related information of a CSK modulation signal of a second frequency point is determined through the first tracking related information based on association of different modulation signals of the same satellite; the second tracking related information is determined through the first tracking related information of the non-CSK modulation signal, so that the resource consumption of capturing and tracking of the CSK modulation signal is reduced; and on the basis of the obtained second tracking related information, auxiliary tracking of the CSK modulation signal of the second frequency point is realized under the condition of reducing resource consumption.

Description

Technical Field

[0001] This article relates to satellite positioning technology, and in particular to a signal tracking method, device, computer storage medium, and terminal. Background Art

[0002] Code shift keying (CSK) modulation uses a multi-level mapping scheme to map information bits into different code sequences, expressed as CSK(U, N), where U is the number of bits mapped to a message symbol (corresponding to a code sequence), and N is the number of code periods contained in a CSK symbol. Unlike binary phase shift keying (BPSK) modulation, CSK modulation does not change the pseudo-code rate or code length, but rather increases the code phase offset dimension. This technology does not increase the spectrum width or affect the independence and orthogonality of the pseudo-code, thereby increasing the message rate without affecting anti-interference and ranging performance.

[0003] According to relevant research, CSK, as a new modulation method, is being gradually introduced into the GNSS system to optimize system performance, improve positioning accuracy and service quality. The application methods may include the following three methods: (1) On the same branch, CSK modulated signals and non-CSK modulated signals are broadcast simultaneously using time division multiplexing. For example, the previous application with the authorization publication number CN110244328B discloses a navigation enhancement signal modulation method and system, which uses code period time division multiplexing technology in the same signal and alternately uses BPSK and CSK to broadcast different types of telegrams; for example, the L61 signal broadcast by the Quasi-Zenith Satellite System (QZSS) uses CSK without telegrams and CSK modulated signals alternately in the same signal to broadcast different types of telegrams. (2) Using the QPSK modulation method, a CSK modulated signal is broadcast on the I branch or the Q branch, while a non-CSK modulated signal is broadcast on the other branch. For example, the previous application with the authorization publication number CN109194362A discloses a dual-rate composite telegram signal broadcast control method, which uses a traditional BPSK signal on the I branch and a CSK signal on the Q branch; (3) Using a single frequency point to broadcast a standard CSK modulated signal. For a system with multiple frequency points, high-speed telegram information can be provided to users with high requirements. For example, the L62 signal broadcast by satellites such as QZS02, 03 and 04 of the QZSS system is characterized by alternating two CSK signals modulating different telegrams in the same signal to broadcast different types of telegrams.

[0004] The tracking method of CSK modulated signal in related art requires a lot of resources. The following is a brief description of the method in related art: (1) Using the time domain cyclic correlation method, the correlator is used to obtain the correlation value of the traversal calculation of the phase offset of various pseudo-random codes. Even if the simplest early-late code correlator is used, it requires 3 times S (S=2 U ) correlators, resulting in a large number of correlators; (2) the frequency domain conjugate multiplication method is used, that is, the discrete Fourier transform (DFT) is used to increase the operation speed, which requires two N-point DFTs and one N-point IDFT (N≥S). The module scale is large, and the DFT module increases cost and power consumption. In addition, in the related art, CSK modulated signals are used for telegram parsing. When the CSK modulated signal is used to decipher the telegram, the telegram is mapped to the pseudo-random code, which changes the initial phase of the pseudo-random code period. As a result, the code phase obtained by capture and tracking has a certain degree of ambiguity due to the telegram, resulting in the pseudo-code phase ambiguity in the capture of the CSK modulated signal, and the capture and tracking function cannot be realized.

[0005] In summary, the capture and tracking of CSK modulated signals in related technologies requires a large amount of resources. How to achieve the capture and tracking of CSK modulated signals while reducing resource application has become a problem to be solved. Summary of the Invention

[0006] The present invention provides a signal tracking method, including: Capturing first tracking-related information of a received first radio frequency signal, wherein the first radio frequency signal is a non-CSK modulated signal of a first frequency point of the satellite, and the first tracking-related information includes a first carrier Doppler frequency of the first radio frequency signal, a first pseudo code Doppler frequency, a first pseudo code phase, and a pseudo code period of the first pseudo code phase within a message symbol; Determining second tracking-related information for a second radio frequency signal based on the first tracking-related information, wherein the second radio frequency signal is a CSK modulated signal at a second frequency point of the satellite, and the second tracking-related information includes a second carrier Doppler frequency, a second pseudo code Doppler frequency, and a second pseudo code phase of the second radio frequency signal; Tracking processing is performed on the second radio frequency signal according to the determined second tracking related information.

[0007] On the other hand, an embodiment of the present application provides a signal tracking device, comprising: a first channel unit and a second channel unit; wherein, The first channel unit is configured to capture first tracking-related information of a received first radio frequency signal, wherein the first radio frequency signal is a non-CSK modulated signal of a first frequency point of the satellite, and the first tracking-related information includes a first carrier Doppler frequency of the first radio frequency signal, a first pseudo code Doppler frequency, a first pseudo code phase, and a pseudo code period of the first pseudo code phase within a message symbol. The second channel unit includes a tracking processing subunit, which is configured to: determine second tracking related information of the second radio frequency signal based on the first tracking related information; and track the second radio frequency signal based on the determined second tracking related information; wherein the second radio frequency signal is a CSK modulated signal of the second frequency point of the satellite, and the second tracking related information includes a second carrier Doppler frequency, a second pseudo code Doppler frequency, and a second pseudo code phase of the second radio frequency signal.

[0008] On the other hand, an embodiment of the present application further provides a computer storage medium, wherein the computer storage medium stores a computer program, and when the computer program is executed by a processor, the above-mentioned signal tracking method is implemented.

[0009] In another aspect, an embodiment of the present application further provides a terminal, comprising: a memory and a processor, wherein the memory stores a computer program; The processor is configured to execute the computer program in the memory; When the computer program is executed by the processor, the signal tracking method described above is implemented.

[0010] The disclosed embodiment reduces resource consumption for capturing and tracking the CSK modulated signal by capturing and tracking first tracking-related information of a non-CSK modulated signal at a first frequency point, determining second tracking-related information of a CSK modulated signal at a second frequency point based on the association of different modulated signals of the same satellite through the first tracking-related information, and determining the second tracking-related information through the first tracking-related information of the non-CSK modulated signal; and based on the obtained second tracking-related information, achieving auxiliary tracking of the CSK modulated signal at the second frequency point while reducing resource consumption.

[0011] Other features and advantages of the present application will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present application. Other advantages of the present application can be realized and obtained by the solutions described in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The accompanying drawings are used to provide an understanding of the technical solution of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solution of the present application and do not constitute a limitation on the technical solution of the present application.

[0013] Figure 1 This is a flowchart of a signal tracking method according to an embodiment of the present disclosure; Figure 2 This is a structural block diagram of a signal tracking device according to an embodiment of the present disclosure; Figure 3 Schematic diagram of the composition of the first channel unit according to an embodiment of the present disclosure; Figure 4Schematic diagram of the composition of the second channel unit in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0014] This application describes multiple embodiments, but this description is exemplary rather than restrictive, and it will be apparent to those skilled in the art that there may be more embodiments and implementations within the scope of the embodiments described herein. Although many possible feature combinations are shown in the drawings and discussed in the detailed description, many other combinations of the disclosed features are also possible. Unless specifically limited, any feature or element of any embodiment may be used in combination with any other feature or element in any other embodiment, or may replace any other feature or element in any other embodiment.

[0015] The present application includes and contemplates combinations of features and elements known to those of ordinary skill in the art. The embodiments, features, and elements disclosed in this application may also be combined with any conventional features or elements to form a unique inventive solution. Any features or elements of any embodiment may also be combined with features or elements from other inventive solutions to form another unique inventive solution. Therefore, it should be understood that any feature shown and / or discussed in this application may be implemented individually or in any appropriate combination. Therefore, except for the limitations made according to the appended claims and their equivalents, the embodiments are not subject to other limitations. In addition, various modifications and changes may be made within the scope of protection of the appended claims.

[0016] In addition, when describing representative embodiments, the specification may have presented the method and / or process as a specific sequence of steps. However, to the extent that the method or process does not rely on the specific order of the steps described herein, the method or process should not be limited to the steps in the specific order described. As will be understood by those skilled in the art, other orders of steps are also possible. Therefore, the specific order of the steps set forth in the specification should not be interpreted as a limitation to the claims. In addition, the claims for the method and / or process should not be limited to performing their steps in the order written, and those skilled in the art can readily understand that these orders can be changed and still remain within the spirit and scope of the embodiments of the present application.

[0017] Figure 1 This is a flow chart of the signal tracking method according to an embodiment of the present disclosure. Figure 4 As shown, including: Step 101: Capture first tracking-related information of a received first radio frequency signal, wherein the first radio frequency signal is a non-CSK modulated signal of a satellite at a first frequency point, and the first tracking-related information includes a first carrier Doppler frequency, a first pseudo code Doppler frequency, a first pseudo code phase, and a pseudo code period of the first pseudo code phase within a message symbol of the first radio frequency signal. Step 102: Determine second tracking-related information of a second radio frequency signal based on the first tracking-related information, wherein the second radio frequency signal is a CSK modulated signal of a second frequency point of the satellite, and the second tracking-related information includes a second carrier Doppler frequency, a second pseudo-code Doppler frequency, and a second pseudo-code phase of the second radio frequency signal. Step 103: Track the second radio frequency signal according to the determined second tracking related information.

[0018] The disclosed embodiment reduces resource consumption for capturing and tracking the CSK modulated signal by capturing and tracking first tracking-related information of a non-CSK modulated signal at a first frequency point, determining second tracking-related information of a CSK modulated signal at a second frequency point based on the association of different modulated signals of the same satellite through the first tracking-related information, and determining the second tracking-related information through the first tracking-related information of the non-CSK modulated signal; and based on the obtained second tracking-related information, achieving auxiliary tracking of the CSK modulated signal at the second frequency point while reducing resource consumption.

[0019] In an exemplary embodiment, the first frequency point and the second frequency point of the embodiment of the present disclosure may be the same or different, and both may be used to implement the above-mentioned signal tracking processing of the embodiment of the present disclosure.

[0020] The disclosed embodiments can capture first tracking-related information of a received first radio frequency signal with reference to related technologies, including: storing a first intermediate frequency signal of the first radio frequency signal, the first intermediate frequency signal being obtained by subjecting the first radio frequency signal received by the radio frequency front end to signal conditioning methods such as bandpass filtering and amplifiers, followed by down-conversion mixing, intermediate frequency signal filtering and amplification, and analog-to-digital conversion; obtaining a rough estimate of a first carrier frequency and a first pseudo-code phase of the first radio frequency signal before performing signal tracking; replicating a local carrier signal based on parameters provided by a first carrier digitally controlled oscillator to remove the first carrier frequency of the first intermediate frequency signal of the first radio frequency signal, that is, down-converting the first intermediate frequency signal to baseband; replicating a local pseudo-code based on parameters provided by a first pseudo-code generator, cross-correlating the local pseudo-code with the received first radio frequency signal, and performing coherent integration to remove the first pseudo-code and despread the signal; obtaining a first carrier Doppler and a first pseudo-code phase of the first frequency point of the first radio frequency signal; finding a data bit edge and a subframe start edge from the first radio frequency signal; and since one telegram symbol at the first frequency point corresponds to M pseudo-code periods, the module can determine the mth pseudo-code period within one telegram symbol where the current first pseudo-code phase is located.

[0021] In an exemplary embodiment, the embodiment of the present disclosure determines second tracking-related information of the second radio frequency signal based on the first tracking-related information, including: determining a second carrier Doppler frequency according to the first carrier Doppler frequency of the first radio frequency signal, the first carrier frequency, and the carrier frequency of the second radio frequency signal; determining a second pseudo code Doppler frequency according to a second pseudo code rate of the second radio frequency signal, a second carrier frequency, and the determined second carrier Doppler frequency; The second pseudo code phase is determined based on whether the pseudo code period of the first radio frequency signal is consistent with the pseudo code period of the second radio frequency signal and the first pseudo code phase of the first radio frequency signal.

[0022] In an exemplary embodiment, since the first frequency point and the second frequency point both come from the same satellite, the second carrier Doppler frequency and the second pseudo code phase of the second RF signal can be converted from the first carrier Doppler frequency and the first pseudo code phase of the first RF signal.

[0023] In an exemplary embodiment, the second carrier Doppler frequency of the embodiment of the present disclosure is determined by the following formula: ; Where, represents the second carrier Doppler frequency, represents the first carrier Doppler frequency, represents the first carrier frequency of the first radio frequency signal, The second carrier frequency represents the second radio frequency signal.

[0024] Compared with the related art, the embodiment of the present disclosure omits the carrier tracking loop and calculates the second carrier Doppler frequency based on the first carrier Doppler frequency of the non-CSK modulated signal, thereby saving resources and accelerating the tracking speed.

[0025] In an exemplary embodiment, the second pseudo-code Doppler of the embodiment of the present disclosure is determined by the following formula: ; Where, represents the second pseudo code Doppler frequency, represents the second carrier Doppler frequency, represents a second pseudo code rate of the second radio frequency signal, The second carrier frequency represents the second radio frequency signal.

[0026] In an exemplary embodiment, when the pseudo code period of the first radio frequency signal and the pseudo code period of the second radio frequency signal in the embodiment of the present disclosure are consistent, the second pseudo code phase is determined based on the following formula: ; Where, is the first pseudo code phase, is the second pseudo code phase, is the pseudo code chip width of the first RF signal, , represents a first pseudo code rate of the first radio frequency signal, is the pseudo code chip width of the second RF signal, , The second pseudo code rate of the second radio frequency signal is represented.

[0027] In an exemplary embodiment, when the pseudo code period of the first radio frequency signal and the pseudo code period of the second radio frequency signal are inconsistent, the second pseudo code phase is determined based on the following formula: ; Where, represents the pseudo code period of the first radio frequency signal, The pseudo code period of the second radio frequency signal is represented by the length of one telegram symbol of the first radio frequency signal. , Corresponding to M pseudo code periods, m means that the first RF signal is located in the mth pseudo code period in the message symbol, m≤M, and the length of a message symbol at the second frequency point is , Corresponding to N pseudo code periods, n represents that the second RF signal is located in the nth pseudo code period in the message symbol, n≤N, and , k is the multiple relationship between the message at the second frequency point and the message at the first frequency point, k≤K.

[0028] The pseudo code period of the first frequency radio frequency signal of the embodiment of the present disclosure and the pseudo code period of the second radio frequency signal When they are inconsistent, other parameters can be selected as reference points for synchronization, such as telegrams. Since telegrams are modulated on pseudo-codes, generally speaking, the length of telegram symbols is an integer multiple of the pseudo-code period. That is, the length of a telegram symbol at the first frequency point is Corresponding to M pseudo code cycles, the length of a message symbol at the second frequency point is Corresponding to N pseudo code periods; the length of the message symbol of the first frequency point and the second frequency point generally needs to be an integer multiple relationship, that is, and .

[0029] In an exemplary embodiment, after determining second tracking related information of the second radio frequency signal based on the first tracking related information, the information tracking method of the embodiment of the present disclosure further includes: The pseudo code phase of the correlator performing tracking processing on the second radio frequency signal is initialized according to the second pseudo code phase in the second tracking related information.

[0030] In an exemplary embodiment, before initializing the pseudo code phase of a correlator that performs tracking processing on the second radio frequency signal, the method of the embodiment of the present disclosure further includes: If the second pseudo code phase is continuous within one pseudo code period, and the interval between the correlators for the advance and lag processing is one pseudo code chip, the correlators for the advance and lag processing are multiplexed; If the second pseudo code phase is discontinuous within one pseudo code period, the processing interval of the early correlator and the late correlator is one pseudo code chip.

[0031] When the second pseudo code phase within a pseudo code period of the embodiment of the present disclosure is continuous, the method described above in the embodiment of the present disclosure is used to configure the multiplexing advance correlator and the lag correlator, and the number of correlators is S+1; when the second pseudo code phase within a pseudo code period is discontinuous, the processing interval of the advance correlator and the lag correlator is 1 pseudo code chip, and the number of correlators is 2S; where S is related to the CSK modulation mode, CSK (U, N), U is the number of bits mapped to a telegram symbol (corresponding to a code sequence), and S=2 U The tracking algorithm of CSK modulated signal requires a large number of correlators. Since a telegram symbol of CSK (U, N) modulated signal represents the initial phase of pseudo code, a telegram symbol is U bit size, that is, S=2 UIf there are two types of correlators, S correlators are needed to represent the pseudocodes with different initial phases; if the most commonly used early and late code correlators are selected, the pseudocodes with each initial phase need three different initial phases: advance, immediate, and lag, that is, at least 3S correlators are needed. The disclosed embodiment abandons the immediate branch, and designs the correlators according to the pseudocode characteristics of the broadcast signal, thereby reducing the number of correlators. In the disclosed embodiment, if the second pseudocode phase is continuous within a pseudocode period, and the interval between the advance and lag correlators is 1 pseudocode chip, the advance and lag correlators can be reused, and the number of correlators is CorrNum=S+1; when the satellite operates in a chip time division multiplexing mode, the second pseudocode phase is not continuous within a pseudocode period, that is, different pseudocode sequences are used alternately with a chip duration as the interval, the advance and lag correlators cannot be reused, and the number of correlators is .

[0032] The number of correlators in the embodiment of the present disclosure The relationship between the pseudo code phase of each correlator and the initial second pseudo code phase is shown in Table 1. The pseudo code phase formula of the sth correlator is expressed as follows: , ; Table 1

[0033] In an exemplary embodiment, when tracking the second radio frequency signal based on the determined second tracking-related information, the information tracking method according to the embodiment of the present disclosure further includes obtaining an advanced autocorrelation amplitude and a lagged autocorrelation amplitude for estimating a phase difference between the replica pseudocode and the signal pseudocode by performing the following processing: When the first correlation integral is generated coherent accumulation results, where represents the number of correlators performing tracking processing on the second radio frequency signal, and the coherent accumulation time is one pseudo code period; According to the generated The coherent accumulation results are traversed to calculate the correlation value of each possible message symbol and determine the maximum correlation value; According to the position corresponding to the determined maximum correlation value, the correlation values ​​of the leading correlator and the lagging correlator are obtained: Determining an advanced autocorrelation amplitude and a lagging autocorrelation amplitude based on the obtained correlation values ​​of the advanced correlator and the lagging correlator; The leading autocorrelation amplitude and the lagging autocorrelation amplitude are used to estimate the phase difference between the replica pseudo code and the signal pseudo code.

[0034] In an exemplary embodiment, the coherent accumulation result of the embodiment of the present disclosure is: ; ; Where, represents the coherent accumulation result of the I branch of the s-th correlator, represents the coherent accumulation result of the Q branch of the sth correlator, represents the baseband signal of branch I when the coherent accumulation time is k, represents the baseband signal of the Q branch when the coherent accumulation time is k, represents the pseudo code when the coherent accumulation time is k, , is the number of discrete point data participating in the correlation operation, , is the sampling frequency, represents the coherent accumulation time; In an exemplary embodiment, the calculation formula for the correlation value of the possible message symbols in the embodiment of the present disclosure is: , ; In an exemplary embodiment, the expression of the correlation value of the advance correlator in the embodiment of the present disclosure is: Where, Indicates the position corresponding to the maximum correlation value; In an exemplary embodiment, the expression of the correlation value of the lag correlator of the embodiment of the present disclosure is: ; In an exemplary embodiment, the leading autocorrelation amplitude of the embodiment of the present disclosure is: ; In an exemplary embodiment, the lag autocorrelation amplitude of the embodiment of the present disclosure is: ; In the formula, CohNum is the number of coherent accumulations, and NCSNum is the number of non-coherent accumulations. The present disclosure also provides a computer storage medium having a computer program stored therein, which implements the above-mentioned signal tracking method when executed by a processor.

[0035] The embodiment of the present disclosure further provides a terminal, comprising: a memory and a processor, wherein a computer program is stored in the memory; The processor is configured to execute the computer program in the memory; When the computer program is executed by a processor, the signal tracking method described above is implemented.

[0036] Figure 2 This is a structural block diagram of the signal tracking device according to an embodiment of the present disclosure. Figure 2 As shown, it includes: a first channel unit and a second channel unit; wherein, The first channel unit is configured to capture first tracking-related information of a received first radio frequency signal, wherein the first radio frequency signal is a non-CSK modulated signal of a first frequency point of the satellite, and the first tracking-related information includes a first carrier Doppler frequency of the first radio frequency signal, a first pseudo code Doppler frequency, a first pseudo code phase, and a pseudo code period of the first pseudo code phase within a message symbol. The second channel unit includes a tracking processing subunit, which is configured to: determine second tracking related information of the second radio frequency signal based on the first tracking related information; and track and process the second radio frequency signal based on the determined second tracking related information; wherein the second radio frequency signal is a CSK modulated signal of the second frequency point of the satellite, and the second tracking related information includes a second carrier Doppler frequency, a second pseudo code Doppler frequency, and a second pseudo code phase of the second radio frequency signal.

[0037] The disclosed embodiment captures first tracking-related information of a non-CSK modulated signal of a first frequency point through a first channel unit, determines second tracking-related information of a CSK modulated signal of a second frequency point based on the association of different modulated signals of the same satellite through the captured and tracked first tracking-related information, and determines second tracking-related information through the first tracking-related information of the non-CSK modulated signal, thereby reducing resource consumption for capturing and tracking the CSK modulated signal; based on the obtained second tracking-related information, auxiliary tracking of the CSK modulated signal of the second frequency point is achieved while reducing resource consumption.

[0038] In an exemplary embodiment, the first frequency point and the second frequency point of the embodiment of the present disclosure may be the same or different, and both may be used to implement the above-mentioned signal tracking processing of the embodiment of the present disclosure.

[0039] Figure 3 This is a schematic diagram of the composition of the first channel unit according to an embodiment of the present disclosure, as shown in FIG. Figure 3 As shown, the first channel unit of the embodiment of the present disclosure may include a first radio frequency signal storage module, a capture module, a first tracking module, a bit synchronization and frame synchronization module; wherein, The first RF signal storage module is configured to store a first intermediate frequency signal of the first RF signal, where the first intermediate frequency signal is obtained by passing the first RF signal received by the RF front end through a signal conditioning method such as a bandpass filter and an amplifier, and then undergoing a process such as down-conversion mixing, intermediate frequency signal filtering and amplification, and analog-to-digital conversion; The capture module is configured to obtain a rough estimate of the first carrier frequency and the first pseudo code phase of the first radio frequency signal before the receiving device performs signal tracking. In the embodiment of the present disclosure, the tracking loop can be initialized by the parameter estimation value in the capture module, and the estimation of the carrier frequency and the pseudo code phase can be gradually refined. In the embodiment of the present disclosure, the basic parameters of the first radio frequency signal may include the first carrier frequency ( , unit Hz), the first pseudo code rate ( , unit chip / s), the first pseudo code cycle ( , unit ms).

[0040] The first tracking module includes a first mixer, a first integration and removal module, a first carrier digitally controlled oscillator, a first pseudo code digitally controlled oscillator, a first pseudo code generator, a first carrier tracking loop and a first pseudo code loop; wherein, The first mixer replicates the local carrier signal according to the parameters provided by the first carrier digitally controlled oscillator, thereby stripping the first carrier frequency of the first intermediate frequency signal of the first radio frequency signal, that is, down-converting the first intermediate frequency signal to baseband; The first integral clearing module copies the local pseudo code according to the parameters provided by the first pseudo code generator, performs a cross-correlation operation between the local pseudo code and the received first radio frequency signal, and implements coherent integration to realize first pseudo code stripping and signal despreading; The first carrier tracking loop and the first pseudo code loop respectively ensure that the locally copied carrier frequency and pseudo code are consistent with the received first RF signal; specifically, the carrier tracking loop and the first pseudo code loop respectively obtain the first carrier Doppler of the first RF signal and the first pseudo code phase of the first RF signal.

[0041] The bit synchronization and frame synchronization module finds the edge of the data bit and the starting edge of the subframe from the received first RF signal. Since one telegram symbol at the first frequency point corresponds to M pseudo code periods, the module can obtain the mth pseudo code period within one telegram symbol at which the current first pseudo code phase is located.

[0042] In an exemplary embodiment, the tracking processing subunit of the embodiment of the present disclosure is configured to determine second tracking related information of the second radio frequency signal based on the first tracking related information, including: Determine a second carrier Doppler frequency of the second radio frequency signal according to the first carrier Doppler frequency of the first radio frequency signal, the first carrier frequency, and the carrier frequency of the second frequency point; determining a second pseudo code Doppler frequency according to a second pseudo code rate of the second radio frequency signal, a second carrier frequency, and the determined second carrier Doppler frequency; The second pseudo code phase of the second RF signal is determined based on whether the pseudo code period of the first RF signal is consistent with the pseudo code period of the second RF signal and the first pseudo code phase of the first RF signal.

[0043] In an exemplary embodiment, since the first frequency point and the second frequency point both come from the same satellite, the second carrier Doppler frequency and the second pseudo code phase of the second radio frequency signal can be converted from the first carrier Doppler frequency and the first pseudo code phase of the first radio frequency signal. The second carrier Doppler frequency of the second frequency point radio frequency signal in the embodiment of the present disclosure can be calculated by the following formula: ; Where, represents the second carrier Doppler frequency, represents the first carrier Doppler frequency, represents a first carrier frequency of the first radio frequency signal, The second carrier frequency represents the second radio frequency signal.

[0044] Compared with the related art, the embodiment of the present disclosure omits the carrier tracking loop and calculates the second carrier Doppler frequency based on the first carrier Doppler frequency of the non-CSK modulated signal, thereby saving resources and accelerating the tracking speed.

[0045] In an exemplary embodiment, the second pseudo-code Doppler of the embodiment of the present disclosure can be calculated by the following formula: ; Where, represents the second pseudo code Doppler frequency, represents the second carrier Doppler frequency, represents a second pseudo code rate of the second radio frequency signal, The second carrier frequency represents the second radio frequency signal.

[0046] In an exemplary embodiment, the tracking processing subunit of the embodiment of the present disclosure is configured to determine the second pseudo code phase of the second RF signal based on whether the pseudo code period of the first RF signal and the pseudo code period of the second RF signal are consistent, combined with the first pseudo code phase of the first RF signal, including: When the pseudo code period of the first RF signal is consistent with the pseudo code period of the second RF signal, the second pseudo code phase may be determined based on the following formula: ; Where, is the first pseudo code phase, is the second pseudo code phase, is the pseudo code chip width of the first RF signal, , represents a first pseudo code rate of the first radio frequency signal, is the pseudo code chip width of the second RF signal, , a second pseudo code rate representing a second radio frequency signal; When the pseudo code period of the first radio frequency signal is inconsistent with the pseudo code period of the second radio frequency signal, the second pseudo code phase may be determined based on the following formula: ; in, represents the pseudo code period of the first radio frequency signal, Indicates the pseudo code period of the second RF signal. The length of a telegram symbol at the first frequency point is , Corresponding to M pseudo code periods, m means that the first RF signal is located in the mth pseudo code period in the message symbol, m≤M, and the length of a message symbol at the second frequency point is , Corresponding to N pseudo code periods, n represents that the second RF signal is located in the nth pseudo code period in the message symbol, n≤N, and , k is the multiple relationship between the message at the second frequency point and the message at the first frequency point, k≤K.

[0047] The pseudo code period of the first radio frequency signal in the embodiment of the present disclosure and the pseudo code period of the second radio frequency signal When they are inconsistent, other parameters can be selected as reference points for synchronization, such as telegrams. Since telegrams are modulated on pseudo-codes, generally speaking, the length of telegram symbols is an integer multiple of the pseudo-code period. That is, the length of a telegram symbol at the first frequency point is Corresponding to M pseudo code cycles, the length of a message symbol at the second frequency point is Corresponding to N pseudo code periods; the length of the message symbol of the first frequency point and the second frequency point generally needs to be an integer multiple relationship, that is, and .

[0048] In an exemplary embodiment, the tracking processing subunit of the embodiment of the present disclosure is further configured to: The pseudo code phase of the correlator performing tracking processing on the second radio frequency signal is initialized according to the second pseudo code phase in the determined second tracking related information.

[0049] In an exemplary embodiment, the tracking processing subunit is further configured to configure the correlator according to whether the second pseudo code phase is continuous within the pseudo code period: If the second pseudo code phase is continuous within one pseudo code period, and the interval between the correlators for the advance and lag processing is one pseudo code chip, the advance correlator and the lag correlator are multiplexed; If the second pseudo code phase is discontinuous within one pseudo code period, the processing interval of the early correlator and the late correlator is one pseudo code chip.

[0050] In an exemplary embodiment, when the tracking processing subunit of the embodiment of the present disclosure is configured to perform tracking processing on the second radio frequency signal based on the determined second tracking-related information, the tracking processing subunit includes obtaining an advanced autocorrelation amplitude and a lagged autocorrelation amplitude for estimating a phase difference between the replica pseudocode and the signal pseudocode through the following processing: When the first correlation integral is generated coherent accumulation results, where represents the number of correlators performing tracking processing on the second radio frequency signal, and the coherent accumulation time is one pseudo code period; According to the generated The coherent accumulation results are traversed to calculate the correlation value of each possible message symbol and determine the maximum correlation value; According to the position corresponding to the determined maximum correlation value, the correlation values ​​of the leading correlator and the lagging correlator are obtained: Determining an advanced autocorrelation amplitude and a lagging autocorrelation amplitude based on the obtained correlation values ​​of the advanced correlator and the lagging correlator; The leading autocorrelation amplitude and the lagging autocorrelation amplitude are used to estimate the phase difference between the replica pseudo code and the signal pseudo code.

[0051] In an exemplary embodiment, the coherent accumulation result of the embodiment of the present disclosure is: ; ; Where, represents the coherent accumulation result of the I branch of the s-th correlator, represents the coherent accumulation result of the Q branch of the sth correlator, represents the baseband signal of branch I when the coherent accumulation time is k, represents the baseband signal of the Q branch when the coherent accumulation time is k, represents the pseudo code when the coherent accumulation time is k, , is the number of discrete point data participating in the correlation operation, , is the sampling frequency, represents the coherent accumulation time; Correspondingly, the calculation formula of the correlation value corresponding to the possible message symbol is: , ; The expression of the correlation value of the advance correlator is: ; Where, Indicates the position corresponding to the maximum correlation value; The expression of the correlation value of the delayed correlator is: ; The leading autocorrelation amplitude after coherent accumulation and incoherent accumulation is: ; The lagged autocorrelation amplitude after coherent accumulation and incoherent accumulation is: ; Where CohNum is the number of coherent accumulations, and NCSNum is the number of non-coherent accumulations.

[0052] Figure 4 This is a schematic diagram of the composition of the second channel unit according to an embodiment of the present disclosure, as shown in FIG. Figure 4 As shown, the tracking processing subunit of the embodiment of the present disclosure may include an auxiliary tracking module and a second tracking module; wherein, The auxiliary tracking module is configured to: determine the second tracking related information of the second radio frequency signal according to the pseudo code period in the message symbol where the predetermined second pseudo code phase is located and the first tracking related information; The second tracking module is configured to perform tracking processing on the second radio frequency signal according to the determined second tracking related information.

[0053] In an exemplary instance, the auxiliary tracking module of an embodiment of the present disclosure may include a carrier synchronization submodule, a pseudo code synchronization submodule and a correlator initialization submodule; the embodiment of the present disclosure may set the carrier synchronization submodule to implement the above-mentioned processing of determining the second carrier Doppler frequency; set the pseudo code synchronization module to implement the above-mentioned processing of determining the second pseudo code Doppler frequency and the second pseudo code phase; set the correlator initialization submodule to implement the processing of initializing the pseudo code phase of the correlator used for tracking the second RF signal.

[0054] In an exemplary embodiment, the second channel unit of the embodiment of the present disclosure further includes a second RF signal storage module, which is configured to: process the second RF signal received by the RF front end, obtain the second intermediate frequency signal of the I branch and the second intermediate frequency signal of the Q branch of the second RF signal (i.e. , ); Referring to the relevant technology, the second RF signal storage module can determine the following basic parameters of the second RF signal: the second carrier frequency ( , Hz), the second pseudo code rate ( , chip / s), the second pseudo code length in one cycle (chip) and the second pseudo code cycle ( ).

[0055] The second tracking module of the embodiment of the present disclosure may include a second mixer, a second carrier digitally controlled oscillator, a second pseudo code digitally controlled oscillator, a second pseudo code generator, a first coherent integration submodule, a maximum correlation value query submodule, a second integration clearing submodule and a second pseudo code loop; wherein, The second carrier digitally controlled oscillator accumulates the carrier control word and replicates the carrier phase, thereby replicating the local sine carrier and the local cosine carrier, and maintaining carrier phase synchronization with the received second RF signal. For an L-number digitally controlled oscillator, the expression for the second carrier control word is: second carrier control word = (second carrier intermediate frequency + second carrier Doppler) · 2 L / Sampling frequency.

[0056] The second mixer uses a local sinusoidal carrier replicated by a second carrier digitally controlled oscillator and local cosine carrier , realizing stripping of the carrier frequency of the second intermediate frequency signal of the second radio frequency signal, and obtaining the baseband signal of the I branch and the baseband signal of the Q branch: ; ; in, is the local carrier phase.

[0057] At the initialization moment, the updated second pseudo code Doppler frequency is obtained by the pseudo code synchronization submodule, and the second pseudo code numerically controlled oscillator updates the second pseudo code rate according to the obtained second pseudo code Doppler frequency. The second pseudo code rate expression is: ; At non-initialization time, the error filter value is identified according to the pseudo code (obtained by the second pseudo code loop) and the obtained second carrier Doppler frequency, the expression for determining the second pseudo code rate is: ; The second pseudo code generator updates the second pseudo code phase according to the second pseudo code rate and adjusts the corresponding locally copied pseudo code; since the second radio frequency signal adopts correlators, it will generate Pseudocodes of different phases, that is, , the pseudo code phase relationship corresponding to each pseudo code is shown in Table 1, where .

[0058] The first correlation integration submodule correlates and accumulates the result after the second mixer is mixed with the locally copied pseudo code. Different from the first integration clearing module of the first RF signal, the first correlation integration of the second RF signal adopts the coherent accumulation time of one pseudo code period, i.e., the coherent accumulation time The reason why the coherent accumulation time is one pseudo code period is that if it exceeds one code period, the peak value will be submerged.

[0059] The second RF signal uses correlators, thus generating Coherent accumulation results: A message symbol has S possible values, so S immediate correlation value results need to be compared. Increasing the immediate correlation value requires adding S more correlators, which consumes a lot of resources. The embodiment of the present disclosure only retains the leading and lagging correlators, and the maximum correlation value query submodule performs the following processing to query the maximum correlation value by performing the leading and lagging correlation values: Traverse and calculate the correlation value of each possible message symbol , and determine the maximum correlation value of the query ; According to the position corresponding to the maximum correlation value of this coherent accumulation , determine the correlation value of the early correlator and the correlation value of the late correlator: After obtaining the maximum correlation value, the second integration clearing submodule further performs coherent accumulation and non-coherent accumulation, stores the accumulation result of the second integration clearing, and clears the integration result of the second integration clearing to obtain the leading autocorrelation amplitude and the lagging autocorrelation amplitude: The carrier synchronization submodule provides a second carrier Doppler frequency for the second carrier digitally controlled oscillator and the second pseudo-code loop.

[0060] The second pseudo code loop includes a code loop discriminator and a code loop filter, and has the same structure as the first pseudo code loop of the first channel; wherein, The code ring discriminator is used to estimate the phase difference between the replica pseudo code and the signal pseudo code , the embodiment of the present disclosure may adopt a non-coherent lead-lag amplitude method, with the lead and lag correlator interval being 1 chip; ; Phase Difference As the input of the code loop filter, the code loop filter filters out the high-frequency noise in the identification result and obtains the phase difference The filtered value , as the input of the second pseudo-code numerically controlled oscillator, to correct the second pseudo-code rate of the second radio frequency signal.

[0061] The correlator method in the related art (especially the early-late code correlator) requires 3S correlators (S is the total number of possible symbols of a message, S=2 U), which consumes a lot of correlator resources, while the DFT method requires at least two N-point DFTs and one N-point IDFT (N≥S), which consumes a lot of cost and power. The embodiment of the present disclosure omits the early and late code correlators of the immediate branch, and only uses the integration results of the advance correlator and the lag correlator to obtain the coherent accumulation peak. The correlator is designed according to the characteristics of the signal pseudocode, retaining the advantages of the correlator method while reducing the number of correlators. The embodiment of the present disclosure uses the first tracking-related information of the first frequency point to assist the CSK modulated signal in capturing and tracking the second frequency point, so that the carrier tracking loop can be omitted for tracking the CSK modulated signal, further reducing resources and providing an independent observation of the CSK modulated signal.

[0062] This disclosed embodiment uses the L62 signal broadcast by the QZSS system as an example. This signal broadcasts the Centimeter-Level Augmentation Service (CLAS) over the L6 frequency and supports the Precise Orbit and Clock Estimation System (MADOCA). To support both services, the L62 signal uses chip time-division multiplexing to simultaneously broadcast the L6D and L6E signals. Both signals use CSK (8,1) modulation technology. The L62 signal broadcast by the QZSS system uses CSK (8,1) modulation technology. The first channel unit needs to capture and track non-CSK-modulated GNSS signals from the same satellite, such as L1C / A, L2C, and L5 signals. The second channel unit tracks the L62 signal from the same satellite.

[0063] It should be noted that if the influence of the ionosphere is taken into account, the first channel can use a frequency signal close to the L6 frequency, such as L2C and L5; if tracking stability is considered, the first frequency can be selected from the most commonly used frequency signals. The first frequency processed by the first channel unit in the embodiment of the present disclosure is the L1C / A signal.

[0064] In the embodiment of the present disclosure, the first channel unit captures and tracks the first tracking-related information of the first frequency point based on the received first RF signal. In the embodiment of the present disclosure, a telegram symbol period of the GPS L1C / A signal is 20 ms, including 20 code periods, that is, M=20. During the bit synchronization and frame synchronization processing, it can be obtained that the current first pseudo code phase is in the mth pseudo code period within a telegram symbol.

[0065] The first channel unit tracks the first RF signal of GPS L1C / A frequency point. The basic parameters include: first carrier frequency , the first pseudo code rate , the first pseudo code cycle is .

[0066] The second frequency point of the disclosed embodiment is QZSS L62 frequency point. The second channel unit tracks the second RF signal of QZSS L62 frequency point. This frequency point adopts CSK (8, 1) modulation signal. The basic parameters include: the second carrier frequency , the second pseudo code rate , the second pseudo code period is .

[0067] When determining the second pseudo code phase in the embodiment of the present disclosure, given that the pseudo code period of the L1C / A frequency point is inconsistent with the pseudo code period of the L62 frequency point, the telegram is selected as the reference point for synchronization. The length of a telegram symbol at the first frequency point is , corresponding to 20 pseudo code cycles, that is, M=20, the length of a telegram symbol at the second frequency point is Corresponding to one pseudo code period, N=1; the relationship between the length of the first frequency point and the second frequency point is Right now The pseudo code phase relationship between the first RF signal and the second RF signal is as follows: ; Different from the correlators in related technologies, the tracking algorithm of CSK modulated signals requires a large number of correlators. Since the QZSS L62 signal adopts the CSK (8, 1) modulation method, a telegram symbol represents the initial phase of the pseudo code, and a telegram symbol is 8 bits in size, that is, S=2 8 = 256, then S correlators are needed to represent the pseudocodes with different initial phases; if the most commonly used early and late code correlators are selected, each pseudocode with an initial phase requires three different pseudocodes with different initial phases: advance, immediate, and lag, that is, at least 3S correlators are needed; the embodiment of the present disclosure abandons the immediate branch, because the QZSS L62 signal adopts the chip time division multiplexing technology, the pseudocode phase is not continuous within a pseudocode period, and the correlators are used alternately with a chip duration as an interval, so the advance and lag correlators cannot be reused, so the number of correlators is The correlator interval is 1 chip.

[0068] According to the current actual second pseudo code phase The relationship between the pseudo code phase of each correlator and the actual second pseudo code phase is shown in Table 2. The pseudo code phase formula of correlator s is expressed as follows. The number of correlators 2S.

[0069] , ; Table 2

[0070] Those skilled in the art will appreciate that all or some of the steps, systems, and functional modules / units in the methods, systems, and devices disclosed above may be implemented as software, firmware, hardware, or any combination thereof. In hardware implementations, the division between functional modules / units described above does not necessarily correspond to the division between physical components; for example, a physical component may have multiple functions, or a function or step may be performed collaboratively by several physical components. Some or all components may be implemented as software executed by a processor, such as a digital signal processor or microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit. Such software may be distributed on computer-readable media, which may include computer storage media (or non-transitory media) and communication media (or transient media). As is well known to those skilled in the art, the term "computer storage media" encompasses volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information, such as computer-readable instructions, data structures, program modules, or other data. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store the desired information and can be accessed by a computer. In addition, as is well known to those skilled in the art, communication media typically embodies computer-readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transport mechanism, and may include any information delivery media.

Claims

1. A signal tracking method, characterized in that: include: Capturing first tracking-related information of a received first radio frequency signal, wherein the first radio frequency signal is a non-CSK modulated signal of a first frequency point of the satellite, and the first tracking-related information includes a first carrier Doppler frequency of the first radio frequency signal, a first pseudo code Doppler frequency, a first pseudo code phase, and a pseudo code period of the first pseudo code phase within a message symbol; Determining second tracking-related information for a second radio frequency signal based on the first tracking-related information, wherein the second radio frequency signal is a CSK modulated signal at a second frequency point of the satellite, and the second tracking-related information includes a second carrier Doppler frequency, a second pseudo code Doppler frequency, and a second pseudo code phase of the second radio frequency signal; Tracking processing is performed on the second radio frequency signal according to the determined second tracking related information.

2. The signal tracking method according to claim 1, characterized in that: The determining, based on the first tracking related information, second tracking related information of the second radio frequency signal includes: determining a second carrier Doppler frequency according to the first carrier Doppler frequency of the first radio frequency signal, the first carrier frequency, and the carrier frequency of the second radio frequency signal; Determining the second pseudo code Doppler frequency according to the second pseudo code rate of the second radio frequency signal, the second carrier frequency, and the determined second carrier Doppler frequency; The second pseudo code phase is determined based on whether the pseudo code period of the first radio frequency signal is consistent with the pseudo code period of the second radio frequency signal and in combination with the first pseudo code phase of the first radio frequency signal.

3. The signal tracking method according to claim 2, wherein: The second carrier Doppler frequency is determined by the following formula: ； Where, represents the second carrier Doppler frequency, represents the first carrier Doppler frequency, represents a first carrier frequency of the first radio frequency signal, a second carrier frequency representing the second radio frequency signal; The second pseudo code Doppler is determined by the following formula: ； Where, represents the second pseudo code Doppler frequency, represents the second carrier Doppler frequency, represents a second pseudo code rate of the second radio frequency signal, a second carrier frequency representing the second radio frequency signal; When the pseudo code period of the first radio frequency signal is consistent with the pseudo code period of the second radio frequency signal, the second pseudo code phase is determined based on the following formula: ； Where, is the first pseudo code phase, is the second pseudo code phase, is a chip width of the pseudo code of the first radio frequency signal, , represents a first pseudo code rate of the first radio frequency signal, is a pseudo code chip width of the second radio frequency signal, , a second pseudo code rate representing the second radio frequency signal; When the pseudo code period of the first radio frequency signal is inconsistent with the pseudo code period of the second radio frequency signal, the second pseudo code phase is determined based on the following formula: ； Where, represents the pseudo code period of the first radio frequency signal, represents the pseudo code period of the second radio frequency signal, and the length of a telegram symbol at the first frequency point is , Corresponding to M pseudo code periods, m indicates that the first radio frequency signal is located in the mth pseudo code period in the message symbol, m≤M, and the length of a message symbol at the second frequency point is , Corresponding to N pseudo code periods, n represents that the second radio frequency signal is located in the nth pseudo code period in the message symbol, n≤N, and , k is the multiple relationship between the message at the second frequency point and the message at the first frequency point, k≤K.

4. The signal tracking method according to any one of claims 1 to 3, characterized in that: The determining, based on the first tracking related information, second tracking related information of the second radio frequency signal, the signal tracking method further comprises: The pseudo code phase of a correlator that performs tracking processing on the second radio frequency signal is initialized according to the second pseudo code phase in the second tracking related information.

5. The signal tracking method according to claim 4, characterized in that: Before initializing the pseudo code phase of a correlator that tracks the second RF signal based on the second pseudo code phase in the second tracking related information, the signal tracking method further includes: configuring the correlator through the following processing based on whether the second pseudo code phase is continuous within a pseudo code period: If the second pseudo code phase within one pseudo code period is continuous, and the interval between the correlators for the advance and lag processing is one pseudo code chip, the advance correlator and the lag correlator are multiplexed; If the second pseudo code phase within one pseudo code period is discontinuous, the processing interval of the early correlator and the late correlator is one pseudo code chip.

6. The signal tracking method according to claim 4, characterized in that: The tracking processing of the second radio frequency signal according to the determined second tracking related information includes obtaining an advanced autocorrelation amplitude and a lagged autocorrelation amplitude for estimating a phase difference between the replica pseudo code and the signal pseudo code by the following processing: When the first correlation integral is generated coherent accumulation results, where represents the number of correlators performing tracking processing on the second radio frequency signal, and the coherent accumulation time is one pseudo code period; According to the generated The coherent accumulation results are traversed to calculate the correlation value of each possible message symbol, and determine the maximum correlation value; According to the position corresponding to the determined maximum correlation value, the correlation values ​​of the leading correlator and the lagging correlator are obtained: Determining an advanced autocorrelation amplitude and a lagging autocorrelation amplitude based on the obtained correlation values ​​of the advanced correlator and the lagging correlator; The advanced autocorrelation amplitude and the delayed autocorrelation amplitude are used to estimate the phase difference between the replica pseudo code and the signal pseudo code.

7. The signal tracking method according to claim 6, characterized in that: The coherent accumulation result is: ； ； Where, represents the coherent accumulation result of the I branch of the s-th correlator, represents the coherent accumulation result of the Q branch of the sth correlator, represents the baseband signal of branch I when the coherent accumulation time is k, represents the baseband signal of the Q branch when the coherent accumulation time is k, represents the pseudo code when the coherent accumulation time is k, , is the number of discrete point data participating in the correlation operation, , is the sampling frequency, represents the coherent accumulation time; Correspondingly, the calculation formula of the correlation value corresponding to the possible message symbol is: ， ； The expression of the correlation value of the advance correlator is: ； Where, Indicates the position corresponding to the maximum correlation value; The expression of the correlation value of the delayed correlator is: ； The leading autocorrelation amplitude after coherent accumulation and incoherent accumulation is: ； The autocorrelation amplitude after the coherent accumulation and the incoherent accumulation is: ； Where CohNum is the number of coherent accumulations, and NCSNum is the number of non-coherent accumulations.

8. A signal tracking device, characterized in that: include: A first channel unit and a second channel unit; wherein, The first channel unit is configured to capture first tracking-related information of a received first radio frequency signal, wherein the first radio frequency signal is a non-CSK modulated signal of a first frequency point of the satellite, and the first tracking-related information includes a first carrier Doppler frequency of the first radio frequency signal, a first pseudo code Doppler frequency, a first pseudo code phase, and a pseudo code period of the first pseudo code phase within a message symbol. The second channel unit includes a tracking processing subunit, which is configured to: determine second tracking related information of the second radio frequency signal based on the first tracking related information; and track the second radio frequency signal based on the determined second tracking related information; wherein the second radio frequency signal is a CSK modulated signal of the second frequency point of the satellite, and the second tracking related information includes a second carrier Doppler frequency, a second pseudo code Doppler frequency, and a second pseudo code phase of the second radio frequency signal.

9. A computer storage medium, wherein a computer program is stored in the computer storage medium, and when the computer program is executed by a processor, the signal tracking method according to any one of claims 1 to 7 is implemented.

10. A terminal comprising: A memory and a processor, wherein the memory stores a computer program; wherein, The processor is configured to execute the computer program in the memory; When the computer program is executed by the processor, the signal tracking method according to any one of claims 1 to 7 is implemented.

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