Time-division satellite navigation signal tracking method, device, storage medium, program product, circuit and used pseudo-code generator

Abstract

The present invention discloses a time-division satellite navigation signal tracking method, device, storage medium, program product, circuit and pseudo-code generator used thereby, relating to the field of satellite navigation, and is used to improve the timeliness of loop state update and reduce the loop system complexity. For the intermediate frequency signal of the time-division satellite navigation signal obtained, the present invention uses a local carrier signal to perform carrier stripping; then uses a local pseudo-code signal to perform code stripping, wherein the pseudo-code copies that can be shared in the local pseudo-code signal are grouped, and the signal after carrier stripping is subjected to code stripping in units of groups; then performs an integration and zeroing operation on the signal after code stripping to obtain a coherent result; finally, updates the local carrier signal and the local pseudo-code signal respectively based on the coherent result. The present invention can continuously track the time-division satellite navigation signal and reduces the demand for coherenters.

Description

Technical Field

[0001] The present invention relates to the technical field of satellite navigation, and in particular to a time-division satellite navigation signal tracking method, device, storage medium, program product, circuit and the used pseudo-code generator. Background Art

[0002] For a satellite navigation positioning system, the rapid reception of navigation messages is crucial for the performance of terminal positioning and navigation. To increase the transmission rate of navigation message information and thus improve the real-time performance of navigation message reception, usually two methods can be adopted: one is to increase the code rate of the local pseudo-code signal, such as the pseudo-random code (PseudoRandom Noise, PRN), but this will lead to an increase in the spectral width of the satellite navigation signal; the other is to shorten the chip length of the PRN code, but this will reduce the orthogonality of the PRN code and the information transmission quality.

[0003] To better meet the technical requirements of the positioning and navigation system, some researchers have proposed a coding method that uses PRN sequences of equal length to represent different symbols, such as CSK (Code Shift Keying). Each waveform of CSK modulation is obtained from different cyclic phase shifts of a single basic PRN sequence, so that more information can be transmitted within the same code period without increasing the length of the PRN code, and thus it has a higher information transmission rate. However, since there are multiple cyclic shifts of the PRN code in the same time slot in CSK, the corresponding symbols cannot be directly reproduced locally, so the satellite navigation signal cannot be modulated alone, and other signal components need to be assisted during use, such as BPSK (Binary PhaseShift Keying), etc., to form a time-division BPSK-CSK satellite navigation signal.

[0004] The time-division BPSK-CSK satellite navigation signal means that the BPSK (direct spread spectrum) signal and the CSK signal are alternately transmitted in a time-division manner, and the PRN codes used by both have the same code length and period. However, the known tracking methods for time-division BPSK-CSK satellite navigation signals, as Figure 1 shown, only update the loop (carrier tracking loop PLL (Phase LockedLoop) and code tracking loop DLL (Delay Locked Loop)) state during the BPSK signal time slot, while maintaining the loop state unchanged during the CSK signal time slot, which results in poor timeliness of loop state update and convergence time. In addition, in the code stripping link during the CSK signal time slot, a large number of coherenters are required, and the loop system complexity is relatively high. Summary of the Invention

[0005] The object of the present invention is to provide a time-division satellite navigation signal tracking method, device, storage medium, program product, circuit and the used pseudo-code generator for all or part of the above existing problems, so as to improve the timeliness of loop state update and reduce the complexity of the loop system.

[0006] The technical solution adopted by the present invention is as follows:

[0007] A time-division satellite navigation signal tracking method, which includes:

[0008] Obtain the intermediate frequency signal of the time-division satellite navigation signal;

[0009] Use the local carrier signal to strip the carrier from the intermediate frequency signal;

[0010] Use the local pseudo-code signal to strip the code from the signal after carrier stripping; wherein, group the shareable pseudo-code copies in the local pseudo-code signal, and strip the code from the signal after carrier stripping in units of groups;

[0011] Perform integration and clearing operations on the signal after code stripping to obtain the coherent result;

[0012] Update the local carrier signal and the local pseudo-code signal respectively based on the coherent result.

[0013] To solve the above problems, the present invention also provides a device, including a processor and a storage medium. Computer instructions are stored in the storage medium. When the processor runs the computer instructions, it executes the above time-division satellite navigation signal tracking method.

[0014] To solve the above problems, the present invention also provides a computer-readable storage medium, which stores a computer program. Running the computer program can execute the above time-division satellite navigation signal tracking method.

[0015] To solve the above problems, the present invention also provides a computer program product, including a computer program. When the computer program is run by a processor, it can execute the above time-division satellite navigation signal tracking method.

[0016] On the other hand, the present invention also provides a pseudo-code generator, which is configured to: generate the local pseudo-code signal required for stripping the code from the signal after carrier stripping, group the shareable pseudo-code copies in the local pseudo-code signal for stripping the code from the signal after carrier stripping in units of groups; the signal after carrier stripping is obtained by using the local carrier signal to strip the carrier from the intermediate frequency signal of the time-division satellite navigation signal.

[0017] To solve the above problems, the present invention also provides a time-division satellite navigation signal tracking circuit, which includes a PLL and a DLL, and the above-mentioned pseudo-code generator is arranged on the DLL.

[0018] In summary, due to the adoption of the above technical solutions, the beneficial effects of the present invention are as follows:

[0019] For each time slot of the time-division satellite navigation signal in this application, the intermediate-frequency signal of the time-division satellite navigation signal is acquired, and further carrier stripping, code stripping, and integration resetting are performed to obtain a coherent result, and then the loop state is updated based on the coherent result, that is, continuous tracking in each time slot is achieved, improving the timeliness of signal tracking, thereby improving the loop convergence speed and tracking performance, and avoiding phase errors and frequency errors accumulated due to the lack of loop state update in a certain time slot. In addition, for the case where there is a shared local pseudo-code signal, that is, when there is a shareable local pseudo-code signal in a certain time slot, the shareable pseudo-code copies are grouped, and code stripping is performed in groups, so that only one coherent detector is required for the pseudo-code copies in the same group. Compared with the original loop system where each pseudo-code copy requires a separate coherent detector, the complexity of the loop system is greatly reduced, and the reliability of signal tracking is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention will be described by way of examples with reference to the accompanying drawings, where:

[0021] Figure 1 is a structural diagram of an existing time-division BPSK-CSK satellite navigation signal.

[0022] Figure 2 is a flowchart of the time-division satellite navigation signal tracking method provided by an embodiment of this application.

[0023] Figure 3 is a structural diagram of a time-division BPSK-CSK satellite navigation signal in an embodiment of this application.

[0024] Figure 4 is an example diagram of the CSK codeword generation process in an embodiment of this application.

[0025] Figure 5 is an equivalent diagram of the CSK signal time-slot code generator in an embodiment of this application.

[0026] Figure 6 is a structural diagram of the loop system executed by the time-division satellite navigation signal tracking method provided by an embodiment of this application.

[0027] Figure 7 is an equivalent diagram of the CSK signal time-slot code generator in another embodiment of this application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] All features disclosed in this specification, or steps in all methods or processes disclosed, can be combined in any way, except for mutually exclusive features and / or steps.

[0029] Any feature disclosed in this specification (including any additional claims, abstract) can be replaced by other equivalent or similar-purpose alternative features, unless specifically stated otherwise. That is, unless specifically stated otherwise, each feature is only an example of a series of equivalent or similar features.

[0030] Regarding the problem that the CSK signal cannot be applied alone to satellite navigation signal coding, and the problem of poor timeliness of loop state update and convergence time caused by the existing time-division BPSK-CSK satellite navigation signal tracking method maintaining the loop state unchanged during the CSK signal time slot, as well as the problem of excessive demand for coherenters in the existing time-division BPSK-CSK satellite navigation signal tracking method during the CSK signal time slot, the embodiments of this application provide a time-division satellite navigation signal tracking method, device, storage medium, program product, circuit, and the pseudo-code generator used, aiming to achieve continuous tracking of the time-division BPSK-CSK satellite navigation signal in each time slot and reduce the demand for coherenters in the loop system.

[0031] In some embodiments, as Figure 2 shown, the time-division satellite navigation signal tracking method provided by the embodiments of this application includes the following steps:

[0032] S1. Obtain the intermediate-frequency signal of the time-division satellite navigation signal.

[0033] The time-division satellite navigation signal contains signals with different coding methods, and these signals are sent periodically at intervals in a time-division manner, and the code length and period of each time slot are the same. Taking the time-division BPSK-CSK satellite navigation signal as an example, its signal structure is as Figure 3 shown, the entire transmission frame period is seconds, and the BPSK signal and the CSK signal are alternately sent in a time-division manner at intervals of seconds. The BPSK signal adopts the direct spread-spectrum method. After performing modulo-two operation on the navigation message data and the local pseudo-code signal to obtain the spread-spectrum baseband signal, BPSK modulation is performed to obtain the BPSK signal; the CSK signal represents different CSK codewords by cyclically shifting the initial local pseudo-code signal by different numbers of bits to obtain pseudo-code copies with different phase states. The local pseudo-code signal with a code length of has phase states, and can represent at most different CSK codewords. Taking the PRN code as the local pseudo-code signal, -ary CSK-modulated PRN code first passes through a code delay device and is cyclically shifted to obtain Code sequences with different cyclic shift numbers to represent different CSK codewords. The code delays between different CSK codewords are equal and can be 1 or chip times . Therefore, the number of bit information that a CSK codeword can transmit is U = log 2 M . Then the CSK signal can be expressed as , where is the chip length with a cyclic shift interval. As Figure 4 shown in is a schematic diagram of the generation of modulation symbols, where the length of the PRN code is , and the cyclic shift interval between different symbols is 1 chip. Within seconds, each of the two modulation signals is transmitted times. The two signals use different PRN codes, and the code periods are both seconds, and the code lengths and code rates are the same, which are and respectively, and the chip width is . Then the code period is , and the frame period . The symbol periods of the BPSK signal and the CSK signal are both integer multiples of the code period , that is, one symbol contains 1 to code periods.

[0034] For the obtained time-division satellite navigation signal, the intermediate frequency signal is obtained through down-conversion. In some feasible embodiments, after initially filtering the time-division satellite navigation signal, down-conversion is performed to obtain an analog intermediate frequency signal, and further analog-to-digital conversion is performed to obtain a digital intermediate frequency signal.

[0035] S2. Use the local carrier signal to perform carrier stripping on the intermediate frequency signal.

[0036] The local carrier signal is usually generated by a carrier numerically controlled oscillator (NCO, Numerically Controlled Oscillator), and the local carrier signal includes a local sine carrier and a local cosine carrier.

[0037] In some feasible embodiments, the (digital) intermediate frequency signal obtained in step S1 is multiplied by the local sine carrier and the local cosine carrier respectively to complete carrier stripping, and the in-phase branch (I branch) signal and the quadrature branch (Q branch) signal are obtained correspondingly.

[0038] As an alternative embodiment, assume that the time-division satellite navigation signal is Figure 3The time-division BPSK-CSK satellite navigation signal shown, that is, it includes a BPSK signal and a CSK signal. Let and respectively represent the acquired digital intermediate-frequency BPSK signal and CSK modulation signal, is the sampling interval, is the sampling point sequence number, then:

[0039] ,

[0040] ,

[0041] where is signal amplitude; is the carrier angular frequency of the intermediate-frequency signal; represents the navigation message data carried by the BPSK signal; represents the PRN code sequence of the BPSK signal; represents the codeword corresponding to the CSK signal; represents the initial phase of the signal; and are both Gaussian white noise signals; represents the time slot number, which is an integer and .

[0042] Assume the local sine carrier and the local cosine carrier are respectively:

[0043] ,

[0044] ,

[0045] where is the carrier signal angular frequency generated locally by the receiver (the corresponding frequency is expressed as ); represents the initial phase of the locally generated carrier signal.

[0046] The digital intermediate-frequency signal and are respectively mixed with the local sine signal and the local cosine signal to respectively obtain the I-branch signal and the Q-branch signal, which are respectively:

[0047] ,

[0048] ,

[0049] ,

[0050] ,

[0051] Among them, and are respectively multiplied by and the result of multiplication, and are respectively multiplied by and the result of multiplication; , , , , and are respectively the results after mixing the noise in the BPSK signal and the CSK signal with the local carrier signal.

[0052] By the above mixing operation, the carrier signal can be stripped, and then combined with subsequent integration to filter out high-frequency components.

[0053] S3. Use the local pseudo-code signal to perform code stripping on the signal after carrier stripping.

[0054] The local pseudo-code signal is usually generated by a code generator. In the embodiments of the present application, the code generator generates a PRN sequence as the local pseudo-code signal. Usually, the local pseudo-code signal includes an early pseudo-code copy E, an in-phase pseudo-code copy P, and a late pseudo-code copy L. The phase differences between E and P, and between P and L are equal, and are a predetermined chip length, such as 0.5 chips. The signal after carrier stripping will be multiplied by E, P, and L respectively to complete code stripping.

[0055] For signals with different coding methods, their code stripping methods are different. Assuming that the time-division satellite navigation signal includes a BPSK signal, then in the BPSK signal time slot, step S3 includes:

[0056] The signal after carrier stripping on the I branch is expressed as , and the signal after carrier stripping on the Q branch is expressed as . Multiply the signals and by the pseudo-code copies E, P, and L generated by the code generator respectively, and the code stripping in the BPSK signal time slot is completed.

[0057] Assuming that the time-division satellite navigation signal includes a CSK signal, then in the CSK signal time slot, step S3 includes:

[0058] The code generator generates M groups of local pseudo-code copies locally for the M-ary CSK signal Each group includes an early pseudo-code copy E, an in-phase pseudo-code copy P, and a late pseudo-code copy L. For the symbol , the corresponding pseudo-code copy is represented as , and , where and between and the phase difference is 0.5 chip, , and are 3 initial pseudo-code copies, and the local pseudo-code copies of the remaining groups are obtained by circularly shifting based on the set phase offset (such as 1 code word) on the basis of the initial local pseudo-code copies of this group.

[0059] Since the phase shift between the instantaneous pseudo-code copies corresponding to adjacent CSK code words is fixed, some local pseudo-code copies between different pseudo-code copy groups are consistent. Taking as an example, , the cyclic phase shift between different CSK code words is 1 chip, so the leading pseudo-code copy of the previous symbol and the lagging pseudo-code copy of the next symbol are the same code word and can be shared, that is . In order to reduce the complexity of the loop system and keep the matching degree between the loop state update amount and the signal dynamic change amount as much as possible in the CSK signal time slot, in the CSK signal time slot, the shareable pseudo-code copies in the local pseudo-code signal are grouped, and the code is stripped from the signal after carrier stripping in groups. Taking the CSK signal in the above embodiment as an example, , then as an optional implementation manner, in the CSK signal time slot, the sequence lengths of the pseudo-code copies generated by the code generator are the same, the leading pseudo-code copies and the lagging pseudo-code copies that can be shared in the local pseudo-code signal are grouped, and then the code is stripped from the signal after carrier stripping in groups, which can reduce the demand for the correlator. For example, the leading pseudo-code copies with different local phase shifts generated are accumulated according to a phase offset of 4 chips (adjustable), that is, the leading pseudo-code copies and the lagging pseudo-code copies that can be shared are accumulated according to a predetermined phase offset of 4 chips to form the sum of 4 groups of leading pseudo-code copies, that is, the pseudo-code copy group , where:

[0060] ,

[0061] ,

[0062] ,

[0063] .

[0064] In this way, the local pseudo-code signal generated by the code generator can be equivalent to such asFigure 5 in the form shown, that is, only containing and . The signal after carrier stripping on the I branch is represented as , and the signal after carrier stripping on the Q branch is represented as . Multiply the signals and with and respectively, that is, multiply the pseudo-code copy group with the signal after carrier stripping in groups to complete the code stripping of the signal after carrier stripping. In this way, not only can the demand for coherenters be reduced, but also the coherent calculation speed can be ensured, and the timeliness of signal tracking can be guaranteed.

[0065] S4. Perform integration and zero-clearing operations on the signal after code stripping to obtain the coherent result.

[0066] Still taking the time-division BPSK-CSK satellite navigation signal as an example, after performing integration and zero-clearing operations on the signals after code stripping of the BPSK signal time slots respectively, the coherent results , , , , , are obtained, where is obtained by multiplying the signal with the pseudo-code copy E generated by the code generator and then performing integration and zero-clearing, and , , , , are the same. In this way, the coherent processing (code stripping and integration zero-clearing) of the signal after carrier stripping is completed. Similarly, after performing integration and zero-clearing operations on the signals after code stripping of the CSK signal time slots respectively, the coherent results , , , are obtained, where is obtained by multiplying with and then performing integration and zero-clearing, , , are the same. Therefore, the number of coherenters required is only , while before grouping the shareable pseudo-code copies, the number of coherenters required is . In comparison, the embodiment of the present application reduces coherenters, greatly reducing the complexity of the loop system.

[0067] S5. Update the local carrier signal and the local pseudo-code signal respectively based on the coherent result.

[0068] In addition to the de-coherer, the loop system for signal tracking mainly includes a PLL and a DLL. The PLL mainly includes a carrier phase detector, a carrier loop filter, and a carrier NCO. The DLL mainly includes a code NCO, a code generator, a code loop phase detector, and a code loop filter. The local carrier signal generated by the carrier NCO includes a local sine carrier and a local cosine carrier. The intermediate frequency signal is multiplied by the local sine carrier and the local cosine carrier respectively to complete carrier stripping. After that, the in-phase branch signal and the quadrature branch signal are multiplied by the local pseudo-code signal (including E, P, L) generated by the code generator (separately or in groups) to complete code stripping. The signals of each branch after code stripping are respectively integrated and cleared to obtain the coherent result. For the BPSK signal time slot, the coherent result is expressed as 、 、 、 、 、 ; for the CSK signal time slot, multiple groups of coherent results are obtained, and the symbol corresponding to the maximum coherent result is used as the received CSK codeword , that is, the coherent results corresponding to the instantaneous pseudo-code copies corresponding to each CSK codeword are traversed, and the CSK codeword corresponding to the maximum coherent result is obtained. When the local pseudo-code signal is not grouped, its coherent result is expressed as 、 、 、 、 、 , and when the local pseudo-code signal is grouped, its coherent result is expressed as 、 、 、 . In the BPSK signal time slot, and are input into the carrier loop phase detector to obtain the phase error between the intermediate frequency signal and the local carrier. The local carrier phase error is filtered by the carrier loop filter and then used to adjust the local carrier signal generated by the carrier NCO to keep the local carrier signal in the same frequency and phase as the carrier of the input intermediate frequency signal; , , and It is input into the code loop phase discriminator to obtain the code phase error of the local pseudo-code signal relative to the input intermediate frequency signal. This code phase error is then filtered by the code loop filter and transmitted to the code NCO to adjust the time when the code generator generates the local pseudo-code signal, so as to keep the pseudo-code phases of the local pseudo-code signal and the received intermediate frequency signal consistent. When the correlation result of the branch is the maximum, the adjustment code generator generates the local pseudo-code signal in advance; when the code correlation result is the maximum, it indicates that the code tracking loop correctly tracks the signal; when the correlation result of the code is the maximum, the adjustment code generator delays the generation of the local pseudo-code signal; finally, the dynamic adjustment of the entire code tracking loop is completed, and the locking of the code tracking loop is achieved. Similar to the CSK signal time slot, based on the obtained CSK codeword the coherence result corresponding to the local pseudo-code signal, the local carrier signal and the local pseudo-code signal are updated respectively. Specifically, and are input into the carrier loop phase discriminator to obtain the local carrier phase error, and 、 、 、 or 、 is input into the code loop phase discriminator to obtain the code phase error of the local pseudo-code signal relative to the input intermediate frequency signal, and the remaining tracking process is the same as that in the BPSK signal time slot.

[0069] As Figure 6 shown is the basic architecture of the loop system for tracking time-division satellite navigation signals in some optional embodiments of the present application. Referring to this architecture, as an optional implementation manner, the present application uses the carrier-assisted code loop tracking method to track signals. Specifically, in some feasible implementation manners, the output result of the carrier loop filter passes through a multiplier (generating a scale factor), and then is added to the output result of the code loop filter, and the sum of the addition is used to control the output state of the code NCO.

[0070] Then, in the embodiment of the present application, step S5 includes:

[0071] S51. Update the state of the carrier tracking loop PLL based on the coherence result corresponding to the instantaneous pseudo-code copy to update the local carrier signal;

[0072] S52. Update the state of the code tracking loop DLL based on the coherence results corresponding to the early pseudo-code copy and the late pseudo-code copy, and weight the update result of the PLL to the update result of the DLL with a predetermined scale factor to update the local pseudo-code signal.

[0073] The need for a scaling factor is because the Doppler effect on the carrier signal is inversely proportional to the wavelength of the signal. Therefore, for the same relative velocity between the satellite transmitter and receiver, the Doppler effect on the spreading code chip rate is much smaller than that on the carrier, so a scaling factor is needed to weight the Doppler effect on the carrier signal and then apply it to the code tracking loop. In some possible embodiments, the scaling factor for compensating this frequency difference is given by:

[0074] Scaling factor = (spreading code chip rate + Doppler effect) / local carrier frequency.

[0075] According to the above embodiments, the demand for coherenters in the CSK signal time slots can be significantly reduced, and the complexity of the loop system can be lowered. In another alternative embodiment, the embodiments of the present application can further reduce the demand for coherenters in the CSK signal time slots while keeping the loop able to update in a timely manner to adapt to signal dynamic changes as much as possible. In this embodiment, for the CSK signal time slots, step S3 further includes:

[0076] Dividing the prompt pseudocode copy in the local pseudocode signal into a group.

[0077] Taking the CSK signal with M chips as an example, the prompt pseudocode copies of each group in the M groups of local pseudocode signals generated by the code generator are grouped together. Still taking the group as a unit, multiplying the pseudocode copy group after stripping the carrier from the signal and to perform code stripping. In this way, the demand for correlators can be further reduced to 2, and the local pseudocode signals generated by the code generator can always have the peak aligned with the mixing results of the in-phase branch and the quadrature branch.

[0078] In some possible embodiments, the prompt pseudocode copies grouped together are grouped by accumulation. At this time, the code generator is equivalent to the structure shown in Figure 7 . The accumulated pseudocode copies and are multiplied by the signals and respectively to complete code stripping. After code stripping and integrating to clear, the carrier phase error is calculated by the carrier loop discriminator and then the subsequent carrier tracking loop state update process is carried out. In this embodiment, the code phase error cannot be calculated in the CSK signal time slots, so the state of the code tracking loop cannot be updated. The signal tracking method updates the state of the carrier tracking loop (i.e., updates the local carrier signal) with as the period, and with To update the state of the code tracking loop (i.e., the local pseudo-code signal) periodically, although the states of the PLL and DLL are not updated in each time slot, continuous tracking of the satellite navigation signal in each time slot is still achieved, adapting to signal tracking in a high-dynamic environment.

[0079] As mentioned above, for the CSK signal time slot, multiple sets of coherent results are obtained, and the symbol corresponding to the maximum coherent result needs to be selected as the received CSK codeword. As an alternative implementation, selecting this CSK codeword includes:

[0080] Traverse the coherent results of the instantaneous pseudo-code copies corresponding to each CSK codeword on the in-phase branch and the quadrature branch respectively; among them, the coherent result of the in-phase branch is expressed as and the coherent result of the quadrature branch is expressed as .

[0081] Obtain the CSK codeword with the maximum envelope of the coherent results on the in-phase branch and the quadrature branch.

[0082] In some feasible implementations, assuming that the codeword index of the CSK codeword to be searched for is expressed as , then there is:

[0083] ,

[0084] where represents the envelope of the coherent results of the instantaneous pseudo-code copy of the CSK codeword on the in-phase branch and the quadrature branch.

[0085] For the CSK signal time slot, since the CSK signal only carries data through PRN code cyclic shift and there is no phase flip, the carrier phase error can be calculated by the following formula:

[0086] . This calculation method has a larger phase discrimination range.

[0087] This carrier phase error is fed back to the carrier NCO after passing through the carrier loop filter to adjust the phase and frequency of the local carrier signal, realizing the state update of the carrier tracking loop.

[0088] In some alternative implementations, after obtaining the index , according to and , the index values and of the adjacent early and late pseudo-code copy groups are obtained.and an incoherent early-late envelope discriminator is used to obtain the code phase error .

[0089] In some feasible embodiments, the code loop discriminator calculates the code phase error through the following formula :

[0090] .

[0091] The obtained code phase error After being filtered by the DLL loop filter, the code NCO is phase-adjusted jointly with the carrier-assisted Doppler shift to control the phase of the codeword of the local pseudocode signal, so as to realize the state update of the CSK signal time slot code tracking loop.

[0092] To further reduce the complexity of the loop system, as an alternative embodiment, the immediate pseudocode copy of the local pseudocode signal in the BPSK signal time slot reuses the initial immediate pseudocode copy of the local pseudocode signal in the adjacent CSK signal time slot .

[0093] Generally speaking, the time-division satellite navigation signal tracking method provided by the embodiments of the present application ensures continuous tracking of the time-division satellite navigation signal, has a fast loop state update speed, so the loop convergence and locking speeds are faster, and the cumulative error of each time slot is small, so the loop tracking error is small, improving the signal tracking accuracy and the navigation positioning accuracy.

[0094] In some embodiments, the device provided by the embodiments of the present application includes a processor and a storage medium, and computer instructions are stored in the storage medium. When the processor runs the computer instructions, the time-division satellite navigation signal tracking method of the above embodiments can be executed.

[0095] In some embodiments, the computer-readable storage medium provided by the embodiments of the present application stores a computer program, and running the computer program can execute the time-division satellite navigation signal tracking method of the above embodiments.

[0096] In some embodiments, the computer program product provided by the embodiments of the present application includes a computer program, and when the computer program is run by a processor, the time-division satellite navigation signal tracking method of the above embodiments can be executed.

[0097] In the embodiments of the present application, the storage medium mentioned can be any available medium that can be accessed by a computer or a data storage device such as a server or a data center integrating one or more available media. The so-called available medium can be a magnetic medium, such as a floppy disk, a hard disk, a magnetic tape, etc.; it can also be an optical medium, such as a digital video disc (DVD), etc.; it can also be a semiconductor medium, such as a solid state drive (SSD), etc. The processor mentioned is a facility with signal reading function and certain computing ability, including but not limited to a central processing unit (CPU), a graphics processing unit (GPU), various dedicated computing chips or computing units, a digital signal processor (DSP), and any device or apparatus integrating the above facilities.

[0098] According to the concept of the present application, in the embodiments of the present application, a pseudo-code generator (or code generator for short) is further provided, which is configured to: generate a local pseudo-code signal required for code stripping of the signal after carrier stripping, and group the pseudo-code copies that can be shared in the local pseudo-code signal for code stripping of the signal after carrier stripping in units of groups. Among them, the signal after carrier stripping is obtained by performing carrier stripping on the intermediate frequency signal of the time-division satellite navigation signal using a local carrier signal. This pseudo-code generator can reduce the number of correlators during the code stripping stage when performing coherent processing on the signal and improve the processing speed.

[0099] In addition, the embodiments of the present application further provide a time-division satellite navigation signal tracking circuit, which constitutes a loop for time-division satellite navigation signal tracking. The time-division satellite navigation signal tracking circuit includes a PLL and a DLL. Among them, the pseudo-code generator of the above embodiment is provided on the DLL to generate a local pseudo-code signal required for code stripping of the signal after carrier stripping during the code stripping stage, and group the pseudo-code copies that can be shared in the local pseudo-code signal to reduce the number of correlators required during coherent processing in the code stripping stage.

[0100] The present invention is not limited to the foregoing specific embodiments. The present invention extends to any new feature or any new combination disclosed in this specification, and any new method or process step or any new combination disclosed.

Claims

1. A time-division satellite navigation signal tracking method, characterized in that, include: Acquire an intermediate frequency signal of a time-division satellite navigation signal, wherein the time-division satellite navigation signal includes a CSK signal; Using a local carrier signal to perform carrier stripping on the intermediate frequency signal; The signal after carrier stripping is subjected to code stripping by using a local pseudo code signal; wherein, in a CSK signal time slot, pseudo code copies that can be shared in the local pseudo code signal are regrouped, and the signal after carrier stripping is subjected to code stripping in groups; regrouping pseudo code copies that can be shared in the local pseudo code signal comprises: generating M groups of local pseudo code copies locally, where M is a base number of the CSK signal, and each group of local pseudo code copies includes an advanced pseudo code copy, an immediate pseudo code copy, and a delayed pseudo code copy; and accumulating pseudo code copies that can be shared in the local pseudo code signal according to a predetermined phase offset to form a corresponding pseudo code copy group; Perform integration and zeroing operation on the signal after code stripping to obtain a coherent result; The local carrier signal and the local pseudo code signal are updated respectively based on the coherence result.

2. The time-division satellite navigation signal tracking method according to claim 1, wherein The code stripping of the signal after the carrier stripping in groups includes: The signal after the carrier stripping is multiplied in groups.

3. The time-division satellite navigation signal tracking method according to any one of claims 1-2, characterized in that The local pseudo code signal includes an advanced pseudo code copy, an immediate pseudo code copy and a delayed pseudo code copy; Grouping the pseudo code copies that can be shared in the local pseudo code signal, including: The advanced pseudo code replica and the delayed pseudo code replica that can be shared in the local pseudo code signal are grouped.

4. The time-division satellite navigation signal tracking method according to claim 3, wherein Updating the local carrier signal and the local pseudo code signal respectively based on the coherence result, comprising: Update the state of a carrier tracking loop PLL based on the coherence result corresponding to the instantaneous pseudo code copy to update the local carrier signal; The state of the code tracking loop DLL is updated based on the coherent results corresponding to the leading pseudo code replica and the lagging pseudo code replica, and the update result of the PLL is weighted to the update result of the DLL with a predetermined proportional factor to update the local pseudo code signal.

5. The time-division satellite navigation signal tracking method according to claim 3, wherein The time-division satellite navigation signal comprises a code shift keying CSK signal; In the CSK signal time slot, the local carrier signal and the local pseudo code signal are updated respectively based on the coherence result, including: Traverse the coherent results corresponding to the instantaneous pseudo-code copies corresponding to each CSK codeword, and obtain the CSK codeword corresponding to the maximum coherent result; Based on the obtained coherence result corresponding to the local pseudo code signal corresponding to the CSK code word, the local carrier signal and the local pseudo code signal are updated respectively.

6. The time-division satellite navigation signal tracking method according to claim 5, wherein, The traversing the coherent results corresponding to the instantaneous pseudo-code copies corresponding to each CSK codeword to obtain the CSK codeword corresponding to the maximum coherent result includes: The coherent results of the instantaneous pseudo code copies corresponding to each CSK code word in the in-phase branch and the orthogonal branch are respectively traversed; A CSK codeword having the largest envelope of the coherence results in the in-phase branch and the quadrature branch is obtained.

7. The time-division satellite navigation signal tracking method according to claim 3, wherein The time-division satellite navigation signal includes a binary phase shift keying BPSK signal and a CSK signal; an instantaneous pseudo code copy of a local pseudo code signal of a BPSK signal time slot, and an initial instantaneous pseudo code copy of a local pseudo code signal of an adjacent CSK signal time slot is multiplexed.

8. The time-division satellite navigation signal tracking method according to claim 5, wherein In the CSK signal time slot, the code stripping of the signal after carrier stripping by using the local pseudo code signal also includes: The instantaneous pseudo code copies in the local pseudo code signal are grouped into one group.

9. The time-division satellite navigation signal tracking method according to claim 8, wherein The instantaneous pseudo code copies in the local pseudo code signal are divided into a group as follows: Accumulate the instantaneous pseudo code replicas in the local pseudo code signal.

10. A device, comprising a processor and a storage medium, wherein computer instructions are stored in the storage medium, characterized in that, When the processor runs the computer instructions, it executes the time-division satellite navigation signal tracking method as described in any one of claims 1-9.

11. A computer-readable storage medium storing a computer program, characterized in that, Running the computer program can execute the time-division satellite navigation signal tracking method as described in any one of claims 1-9.

12. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by a processor, the time-division satellite navigation signal tracking method as described in any one of claims 1-9 can be executed.

13. A pseudo-code generator is configured to generate a local pseudo-code signal required for code stripping of a signal after carrier stripping. The signal after carrier stripping is obtained by performing carrier stripping on an intermediate-frequency signal of a time-division satellite navigation signal using a local carrier signal. The time-division satellite navigation signal includes a CSK signal. It is characterized in that The pseudo code generator is further configured to: in a CSK signal time slot, regroup the pseudo code copies that can be shared in the local pseudo code signal, so as to perform code stripping on the carrier stripped signal in groups; The pseudo-code copies that can be shared in the local pseudo-code signal are regrouped, including: generating M groups of local pseudo-code copies locally, where M is a base number of the CSK signal, and each group of local pseudo-code copies includes an advanced pseudo-code copy, an immediate pseudo-code copy, and a delayed pseudo-code copy; and accumulating the pseudo-code copies that can be shared in the local pseudo-code signal according to a predetermined phase offset to form a corresponding pseudo-code copy group.

14. A time-division satellite navigation signal tracking circuit, comprising a PLL and a DLL, characterized in that, The pseudo code generator as claimed in claim 13 is arranged on the DLL.

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