GNSS co-star dual-frequency signal baseband carrier / code joint tracking processing method and receiver

Abstract

The present application relates to a kind of GNSS co-star dual-frequency signal baseband carrier / codes joint tracking processing method and receiver, belong to satellite navigation positioning technical field, method includes: using dual-frequency joint carrier tracking loop to carry out the closed loop tracking of dual-frequency carrier;Dual-frequency joint carrier tracking loop, jointly use the carrier phase discrimination result of the carrier tracking loop of each frequency point of dual-frequency point, respectively predict out the carrier loop parameter of control each frequency point to carry out recurring carrier;Using dual-frequency joint code tracking loop to carry out the closed loop tracking of dual-frequency signal code loop;Dual-frequency joint code tracking loop, jointly use the code ring discrimination result of the code tracking loop of each frequency point of dual-frequency point, and combine the carrier phase discrimination result in dual-frequency joint carrier tracking loop, respectively predict out the code loop parameter of control each frequency point code phase control;Through the closed loop tracking of dual-frequency joint carrier tracking loop and dual-frequency joint code tracking loop, realize the tracking of GNSS co-star dual-frequency signal.The present application improves the sensitivity of dual-frequency signal tracking.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of satellite navigation and positioning technology, and in particular to a GNSS co-star dual-frequency signal baseband carrier / code joint tracking processing method and receiver. BACKGROUND

[0002] GNSS system is a satellite-based radio navigation system, which can provide all-weather, uninterrupted, high-precision, real-time navigation and positioning services for various types of carriers on land, sea and air. At present, GNSS has penetrated into various fields of national economy and daily life, such as sea navigation, urban traffic management, commercial logistics management, ship navigation, precise time service, geodetic survey, precision agriculture, etc.

[0003] Multi-frequency navigation signals have unique advantages in ionospheric correction compared to single-frequency navigation signals, and thus have wide application in high-precision navigation. Modern GNSS system signals all exhibit multi-frequency characteristics, for example, the L1 and L2 frequency civilian signals adopted after GPS modernization, the dual-frequency G1 and G2 frequency civilian signals of GLONASS, and the B1, B2 and B3 frequency point signals of Beidou navigation system.

[0004] The signal processing of traditional GNSS dual-frequency receivers is mainly based on independent tracking processing of single-frequency signals. In the tracking stage of signal processing, the output of the carrier tracking loop of one signal (which is generally easy to capture and track, such as the L1 CA signal of GPS system) is used to assist the carrier tracking loop of another signal (which is generally not easy to capture and track, such as the L2 CM and CL signals of GPS), and the carrier loop assists the code loop to complete the capture and tracking of another signal, thereby completing the tracking of the entire dual-frequency signal. Figure 1 As shown in the following figure: based on the correlation of co-star dual-frequency signals, the joint tracking of dual-frequency signals can be realized by the assistance of L1 frequency carrier loop to L2 frequency carrier loop on the basis of traditional single-frequency carrier loop assisting code loop.

[0005] In current digital GPS receivers, for the same loop filter bandwidth, the noise of carrier loop jitter is about 3 orders of magnitude lower than that of code loop. Therefore, the application of carrier-assisted code tracking loop (carrier NCO and code NCO part) in receivers puts the dynamic stress burden on the carrier tracking loop, reduces the order of code loop filter, and makes the very narrow noise bandwidth DLL perform the most accurate pseudorange measurement, thereby improving the accuracy of navigation and positioning.

[0006] The traditional method is used for receiving and processing a satellite signal with dual-frequency signals in a dual-frequency GNSS navigation receiver, which has the following disadvantages in application:

[0007] (1) The tracking of L2 signal depends on the acquisition and tracking of L1 signal, and the loss of lock or abnormal tracking of L1 signal will directly lead to the loss of lock of L2 signal;

[0008] (2) In the process of signal tracking, the L2 signal tracking can obtain the auxiliary information of L1 signal, but the L1 signal cannot obtain the auxiliary information of L2 signal, and the utilization degree of all useful information is not sufficient;

[0009] (3) In the case of low noise ratio, the tracking sensitivity of the signal is relatively low; even if the signal can be continuously tracked, the tracking precision cannot be optimal. SUMMARY

[0010] In view of the above analysis, the present application aims to disclose a GNSS co-star dual-frequency signal baseband carrier / code joint tracking processing method and receiver; solve the problem of low dual-frequency signal tracking sensitivity.

[0011] The present application discloses a GNSS co-star dual-frequency signal baseband carrier / code joint tracking processing method, comprising:

[0012] Step S1, using the constructed dual-frequency joint carrier tracking loop to perform closed-loop tracking of dual-frequency carrier, and reproducing the carrier of dual-frequency signal;

[0013] In the dual-frequency joint carrier tracking loop, the carrier phase discrimination results of the carrier tracking loops of the two frequency points are jointly used to predict the carrier loop parameters for controlling the reproduction of the carrier of each frequency point;

[0014] Step S2, using the constructed dual-frequency joint code tracking loop to perform closed-loop tracking of the code loop of dual-frequency signal, and controlling the code phase of the code generator of dual-frequency signal;

[0015] In the dual-frequency joint code tracking loop, the code loop discrimination results of the code tracking loops of the two frequency points are jointly used in combination with the carrier phase discrimination results in the dual-frequency joint carrier tracking loop to predict the code loop parameters for controlling the code phase control of each frequency point;

[0016] Step S3, through the closed-loop tracking of the dual-frequency joint carrier tracking loop and the dual-frequency joint code tracking loop, the tracking of the GNSS co-star dual-frequency signal is realized.

[0017] Further, in step S1, the closed-loop tracking process of the dual-frequency signal carrier loop comprises:

[0018] 1) using the phase discrimination result of the first carrier discriminator in the first frequency point carrier loop and the phase discrimination result of the second carrier discriminator in the second frequency point carrier loop to carry out sum and difference processing to obtain a first sum result and a first difference result;

[0019] 2) outputting the first sum result to the first carrier loop filter in the first frequency point carrier loop to carry out loop filtering; outputting the first difference result to the second carrier loop filter in the second frequency point carrier loop to carry out loop filtering;

[0020] 3) according to the filtering results output by the first carrier loop filter and the filtering results output by the second carrier loop filter, carrying out carrier loop parameter prediction to obtain the carrier loop parameters for controlling the first and second frequency point replica carriers;

[0021] 4) using the carrier loop parameters of the first and second frequency point replica carriers to control the replica carrier frequencies in the first and second frequency point carrier loops respectively to carry out closed loop tracking on the first and second frequency point signal carrier loops.

[0022] Further, in the carrier loop parameter prediction, the phase discrimination values of the first and second frequency point carrier loops are recovered; wherein the carrier loop parameter of the first frequency point replica carrier is the sum of the filtering results output by the first and second carrier loop filters; and the carrier loop parameter of the second frequency point replica carrier is the difference between the filtering results output by the first and second carrier loop filters.

[0023] Further, in step S2, the closed loop tracking process of the dual frequency signal code loop comprises:

[0024] 1) using the discrimination result of the first code ring discriminator in the first frequency point code loop and the discrimination result of the second code ring discriminator in the second frequency point code loop to carry out difference and sum processing to obtain a second difference result and a second sum result;

[0025] 2) outputting the second sum result to the first code ring filter to carry out filtering, and then carrying out sum with the filtered first sum result output by the first carrier loop filter to obtain a third sum result; outputting the second difference result to the second code ring filter to carry out filtering, and then carrying out sum with the filtered first difference result output by the second carrier loop filter to obtain a fourth sum result;

[0026] 3) according to the third sum result and the fourth sum result, carrying out code loop parameter prediction to predict the code loop parameters for controlling the first and second frequency point code phases;

[0027] 4) using the predicted code loop parameters for controlling the first and second frequency point code phases to control the code phases of the code generators in the first and second frequency point code loops respectively to carry out closed loop tracking on the first and second frequency point signal carrier loops.

[0028] Further, the discriminator values of the first and second frequency point code loops are recovered in the code loop parameter prediction; wherein the code loop parameter of the first frequency point is the sum of the third and result and the fourth and result; and the code loop parameter of the second frequency point is the difference between the third and result and the fourth and result.

[0029] Further, the dual-frequency signal is any type of GNSS co-star and is derived from a unified clock source.

[0030] Further, the first carrier loop filter and the first carrier loop filter are high-order large-bandwidth filters; and the second carrier loop filter and the second carrier loop filter are low-order narrow-bandwidth filters.

[0031] The application also discloses a GNSS receiver which adopts the co-star dual-frequency signal baseband carrier / code joint tracking processing method to perform carrier tracking and code tracking; and comprises a dual-frequency joint carrier tracking loop and a dual-frequency joint code tracking loop.

[0032] The dual-frequency joint carrier tracking loop jointly uses the phase discrimination results of the respective carrier loops of the dual-frequency points, respectively predicts the carrier loop parameters of the respective frequency points, performs carrier reproduction control, and realizes closed-loop tracking of the dual-frequency signal carrier loop.

[0033] The dual-frequency joint code tracking loop jointly uses the phase discrimination results of the respective code tracking loops of the dual-frequency points, respectively predicts the code loop parameters for controlling the code phases of the respective frequency points in combination with the respective carrier loop filtering results in the dual-frequency joint carrier tracking loop, performs code phase control, and realizes closed-loop tracking of the dual-frequency signal code loop.

[0034] Further, the dual-frequency signal carrier loop comprises a first carrier phase discriminator, a second carrier phase discriminator, a first and module, a first difference module, a first carrier loop filter, a second carrier loop filter and a carrier loop parameter prediction module.

[0035] The input end of the first carrier phase discriminator is connected to the integrated and accumulated results of the current code branch of the first frequency point I path and the integrated and accumulated results of the current code branch of the first frequency point Q path; and the input end of the second carrier phase discriminator is connected to the integrated and accumulated results of the current code branch of the second frequency point I path and the integrated and accumulated results of the current code branch of the second frequency point Q path.

[0036] The output ends of the first carrier phase discriminator and the second carrier phase discriminator are respectively connected to the two input ends of the first and module and the first difference module.

[0037] The first and module and the first difference module respectively perform and processing and difference processing on the phase discrimination results of the first carrier phase discriminator and the second carrier phase discriminator; and the output ends respectively output the first and result and the first difference result.

[0038] The input ends of the first carrier loop filter and the second carrier loop filter input the first sum result and the first difference result respectively; the filtered first sum result and the filtered first difference result output by the first carrier loop filter and the second carrier loop filter are input to a carrier loop parameter prediction module;

[0039] The carrier loop parameter prediction module predicts the carrier loop parameters of the first frequency point and the second frequency point respectively and outputs the carrier loop parameters to the first frequency point and the second frequency point for controlling the carrier reproduction.

[0040] Further, the dual-frequency signal code loop comprises a first code loop discriminator, a second code loop discriminator, a second sum module, a second difference module, a first code loop filter, a second code loop filter, a third sum module, a fourth sum module and a code loop parameter prediction module.

[0041] The input end of the first code loop discriminator is connected to the first frequency point early path and late path despread results; the input end of the second code loop discriminator is connected to the second frequency point early path and late path despread results.

[0042] The output ends of the first code loop discriminator and the second code loop discriminator are connected to the two input ends of the second sum module and the second difference module respectively.

[0043] The second sum module and the second difference module perform summing and difference processing on the discrimination results of the first code loop discriminator and the second code loop discriminator respectively; the output ends output the second sum result and the second difference result respectively.

[0044] The input ends of the first code loop filter and the second code loop filter are connected to the second sum result and the second difference result respectively; the output end of the first code loop filter and the output end of the first carrier loop filter are connected to the two input ends of the third sum module respectively; the output end of the second code loop filter and the output end of the second carrier loop filter are connected to the two input ends of the fourth sum module respectively.

[0045] The filtered second sum result of the first code loop filter and the filtered first sum result of the first carrier loop filter are summed in the third sum module.

[0046] The filtered second difference result of the second code loop filter and the filtered first difference result of the second carrier loop filter are summed in the fourth sum module.

[0047] The output ends of the third sum module and the fourth sum module are connected to the input end of the code loop parameter prediction module.

[0048] The code loop parameter prediction module predicts the code loop parameters for controlling the code phase of the first frequency point and the second frequency point respectively and outputs the code loop parameters to the code generator of the first frequency point and the second frequency point for closed-loop tracking of the first frequency point signal code loop and the second frequency point signal code loop.

[0049] The present application can realize one of the following beneficial effects:

[0050] The disclosed GNSS co-star dual-frequency signal baseband carrier / code joint tracking processing method and receiver, aiming at the defects of the traditional GNSS co-star dual-frequency signal baseband tracking method, realizes mutual assistance of the dual-frequency signal carrier / code tracking loop by coupling the dual-frequency signal carrier / code tracking loop in the dual-frequency signal tracking stage.

[0051] The scheme in the present application is suitable for baseband tracking processing of various GNSS co-star dual-frequency signals, and its requirement for the dual-frequency signal is that the dual-frequency signal source is from the same clock source, and its advantages are as follows:

[0052] (1) By separately filtering the carrier loop and the difference loop, the signal dynamic of the difference loop can be further reduced, thereby reducing the tracking thermal noise bandwidth and improving the tracking sensitivity of the difference loop;

[0053] (2) By the carrier loop and the code loop and the difference loop, the dual-frequency mutual assistance of the carrier / code loop signal is realized, and the dual-frequency signal tracking sensitivity is improved;

[0054] (3) By using the carrier loop and the difference branch to assist the code tracking loop and the difference branch, the tracking bandwidth of the code loop is further reduced, and the code loop tracking sensitivity is improved;

[0055] (4) By using the mutual assistance of the carrier loop and the difference branch and the code loop and the difference branch, mutual coupling in the dual-frequency signal tracking process is realized, so as to realize carrier / code joint tracking processing and improve the dual-frequency signal tracking sensitivity. BRIEF DESCRIPTION OF DRAWINGS

[0056] The accompanying drawings are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiments thereof, and together with the description serve to explain the principle of the present application.

[0057] Figure 1 It is a single-channel dual-frequency signal tracking processing block diagram in the traditional navigation receiver;

[0058] Figure 2 It is a flow chart of the GNSS co-star dual-frequency signal baseband carrier / code joint tracking processing method in the embodiment of the present application;

[0059] Figure 3 It is a single-channel dual-frequency signal tracking processing block diagram of the carrier / code joint tracking processing in the GNSS receiver in the embodiment of the present application. DETAILED DESCRIPTION

[0060] The preferred embodiments of the present application will be specifically described below in combination with the accompanying drawings, wherein the drawings constitute a part of this application, and together with the embodiments of the present application serve to explain the principle of the present application.

[0061] Embodiment one

[0062] One embodiment of the present application discloses a GNSS co-star dual-frequency signal baseband carrier / code joint tracking processing method, as shown in the formula (1), comprising: Figure 2

[0063] Step S1, using the constructed dual-frequency joint carrier tracking loop to perform closed-loop tracking of the dual-frequency carrier, and reproducing the carrier of the dual-frequency signal;

[0064] In the dual-frequency joint carrier tracking loop, the carrier tracking loop parameters for controlling the reproduction of the carrier of each frequency point are respectively predicted by jointly using the carrier phase discrimination results of the carrier tracking loops of the two frequency points;

[0065] Step S2, using the constructed dual-frequency joint code tracking loop to perform closed-loop tracking of the code loop of the dual-frequency signal, and controlling the code phase of the code generator of the dual-frequency signal;

[0066] In the dual-frequency joint code tracking loop, the code loop parameters for controlling the code phase control of each frequency point are respectively predicted by jointly using the code loop discrimination results of the code tracking loops of the two frequency points and combining the carrier phase discrimination results in the dual-frequency joint carrier tracking loop;

[0067] Step S3, through the closed-loop tracking of the dual-frequency joint carrier tracking loop and the dual-frequency joint code tracking loop, the tracking of the GNSS co-star dual-frequency signal is realized.

[0068] Specifically, in step S1, the closed-loop tracking process of the dual-frequency signal carrier loop comprises:

[0069] 1) using the phase discrimination results of the first carrier phase discriminator in the first frequency point carrier loop and the second carrier phase discriminator in the second frequency point carrier loop to perform sum and difference processing to obtain a first sum result and a first difference result;

[0070] Preferably, before performing the sum and difference processing, the phase discrimination results of the first carrier phase discriminator and the second carrier phase discriminator are adjusted and matched according to the proportional relationship of the carrier frequencies of the two frequency points;

[0071] The phase discrimination input of the first carrier phase discriminator is the integration and accumulation results of the current code branch of the I channel and the current code branch of the Q channel of the first frequency point;

[0072] The phase discrimination input of the second carrier phase discriminator is the integration and accumulation results of the current code branch of the I channel and the current code branch of the Q channel of the second frequency point;

[0073] ​2) outputting the sum result to a first carrier loop filter in the first frequency carrier loop for loop filtering, and outputting the difference result to a second carrier loop filter in the second frequency carrier loop for loop filtering;

[0074] Preferably, the sum result and the difference result are respectively subjected to amplitude adjustment before loop filtering, so as to adapt to the input requirement of the loop filter;

[0075] More specifically, the first carrier loop filter for filtering the first sum result adopts a high-order large bandwidth filter, and the second carrier loop filter for filtering the first difference result adopts a low-order narrow bandwidth filter;

[0076] The different signals are subjected to different filter designs, and the common dynamic existing in the first and second frequency points is eliminated based on the first difference result, so that a low-order narrow bandwidth filter can be adopted, thereby reducing the tracking thermal noise bandwidth of the carrier loop and improving the tracking sensitivity of the carrier loop;

[0077] 3) performing carrier loop parameter prediction based on the filtering result output by the first carrier loop filter and the filtering result output by the second carrier loop filter, to obtain the carrier loop parameters for controlling the first and second frequency point recurring carriers;

[0078] Specifically, the phase discrimination values of the first and second frequency point carrier loops are recovered in the carrier loop parameter prediction, wherein the carrier loop parameters for the first frequency point recurring carrier are the sum of the filtering results output by the first and second carrier loop filters, and the carrier loop parameters for the second frequency point recurring carrier are the difference of the filtering results output by the first and second carrier loop filters;

[0079] 4) using the carrier loop parameters of the first and second frequency point recurring carriers to control the recurring carrier frequencies in the first and second frequency point carrier loops, to perform closed loop tracking on the first and second frequency point signal carrier loops.

[0080] Through the closed loop tracking of the dual frequency signal carrier loop in this step, mutual assistance of the dual frequency signals is realized, the defects of the traditional dual frequency carrier tracking are avoided, the common dynamic of the first and second frequency point signals is eliminated, the signal noise output by the loop is low, and the tracking precision is improved.

[0081] In step S2, the closed loop tracking process of the dual frequency signal code loop includes:

[0082] 1) using the discrimination result of a first code loop discriminator in the first frequency point code loop and the discrimination result of a second code loop discriminator in the second frequency point code loop to perform sum and difference processing to obtain a second difference result and a second sum result;

[0083] The discrimination input of the first code loop discriminator is the despread result of the leading code branch and the lagging code branch of the first frequency point.

[0084] The discrimination input of the second code loop discriminator is the despread result of the early code branch and the late code branch of the second frequency point;

[0085] 2) The second sum result is output to the first code loop filter for filtering, and then is summed with the filtered first sum result output by the first carrier loop filter to obtain a third sum result; the second difference result is output to the second code loop filter for filtering, and then is summed with the filtered first difference result output by the second carrier loop filter to obtain a fourth sum result;

[0086] In this step, the first sum result filtered by the first carrier loop filter is summed to assist the first frequency point code loop tracking, and the first difference result filtered by the second carrier loop filter is subtracted to assist the second frequency point code loop tracking, further reducing the dynamic range and bandwidth of the code tracking loop, and improving the sensitivity of the code loop tracking.

[0087] More specifically, the first carrier loop filter filtering the second sum result adopts a high-order large bandwidth filter; the second carrier loop filter filtering the second difference result adopts a low-order narrow bandwidth filter;

[0088] Different filters are designed for different signal dynamics. Since the second difference result eliminates the common dynamics in the two frequency points, a low-order narrow bandwidth filter is adopted, which reduces the tracking thermal noise bandwidth of the code loop and improves the tracking sensitivity of the code loop;

[0089] 3) Code loop parameters for controlling the code phase of the first and second frequency points are predicted according to the third sum result and the fourth sum result;

[0090] Specifically, the discrimination values of the first and second frequency point code loops are recovered in the code loop parameter prediction; the code loop parameter of the first frequency point is the sum of the third sum result and the fourth sum result; and the code loop parameter of the second frequency point is the difference between the third sum result and the fourth sum result;

[0091] By adding the third sum result and the fourth sum result, the tracking parameters of the first frequency point carrier loop are introduced into the tracking of the code loop, realizing the auxiliary tracking of the carrier loop to the code loop in the first frequency point; by subtracting the third sum result and the fourth sum result, the tracking parameters of the second frequency point carrier loop are introduced into the tracking of the code loop, realizing the auxiliary tracking of the carrier loop to the code loop in the second frequency point.

[0092] 4) The code loop parameters predicted for controlling the code phase of the first and second frequency points are used to control the code phase of the code generator in the first and second frequency point code loops respectively, to realize closed-loop tracking of the first and second frequency point signal carrier loops.

[0093] Optionally, the method in the embodiment can be used for baseband tracking processing of various GNSS co-star dual-frequency signals, and the requirement for the dual-frequency signals is that the dual-frequency signals are from the same clock source.

[0094] For example, in the baseband tracking processing of co-star L1 and L2 signals of GPS, Table 1 is a list of characteristics of various dynamic terms of the received dual-frequency signals.

[0095] Table 1

[0096]

[0097] Through the sum path and the difference path of the closed-loop tracking process of the dual-frequency signal carrier loop in the embodiment, the sum path has a dynamic value equivalent to that of the carrier loop in the baseband processing of a conventional receiver, and the difference path eliminates the 2nd, 3rd and 5th dynamic terms in Table 1, so that the dynamic of the loop and the bandwidth are greatly reduced, and the sensitivity of the carrier loop tracking is improved.

[0098] Through the sum path and the difference path of the closed-loop tracking process of the dual-frequency signal code loop in the embodiment, the sum path signal is equivalent to that of the baseband code loop of a conventional receiver, and the difference path eliminates the 2nd, 3rd and 5th dynamic terms in Table 1, so that the dynamic of the loop and the bandwidth are also greatly reduced.

[0099] The outputs of the carrier loop difference path and sum path filters are used to assist the sum path and the difference path of the code loop respectively, so as to further reduce the dynamic of the code tracking loop and the bandwidth, and improve the sensitivity of the code loop tracking. The coupling of the dual-frequency signal carrier / code tracking loops is realized through the sum path and the difference path, the coupling of the carrier loop and the code loop is realized through the carrier loop assisting the sum path and the difference path of the code loop respectively, and the dual-frequency signal carrier / code joint tracking processing is realized through the mutual coupling of the dual-frequency signal carrier loop and the code loop. Therefore, the method has the advantages of realizing the mutual assistance of the dual-frequency signal carrier / code, improving the tracking sensitivity of the dual-frequency signal, etc.

[0100] In summary, the advantages of the GNSS co-star dual-frequency signal baseband carrier / code joint tracking processing method in the embodiment are as follows:

[0101] (1) The signal dynamic of the difference path is further reduced through the separate filtering processing of the carrier loop sum path and difference path, so as to reduce the tracking thermal noise bandwidth and improve the tracking sensitivity of the difference path loop.

[0102] (2) The dual-frequency mutual assistance of the carrier / code loop signals is realized through the carrier loop and the code loop sum path and difference path, and the tracking sensitivity of the dual-frequency signal is improved.

[0103] (3) The tracking bandwidth of the code loop is further reduced through the carrier loop and the difference path assisting the code tracking loop sum path and difference path, and the tracking sensitivity of the code loop is improved.

[0104] (4) using the mutual assistance of the carrier loop and difference branch and the code loop and difference branch, realizing the mutual coupling in the dual-frequency signal tracking process, so as to achieve the carrier / code joint tracking processing and improve the sensitivity of the dual-frequency signal tracking.

[0105] Embodiment two

[0106] Another embodiment of the present application discloses a GNSS receiver which adopts the carrier / code joint tracking processing method of the co-star dual-frequency signal baseband as described in the above embodiment for carrier tracking and code tracking; as shown in the figure, comprising a dual-frequency joint carrier tracking loop and a dual-frequency joint code tracking loop; Figure 3

[0107] The dual-frequency joint carrier tracking loop jointly uses the phase discrimination results of the carrier loops of the two frequency points respectively, predicts the carrier loop parameters of the two frequency points respectively, carries out carrier reproduction control, and realizes the closed-loop tracking of the dual-frequency signal carrier loop;

[0108] The dual-frequency joint code tracking loop jointly uses the phase discrimination results of the code tracking loops of the two frequency points respectively, and combines the carrier loop filtering results of the dual-frequency joint carrier tracking loop, predicts the code loop parameters for controlling the code phases of the two frequency points respectively, carries out code phase control, and realizes the closed-loop tracking of the dual-frequency signal code loop.

[0109] Specifically, the dual-frequency signal carrier loop comprises a first carrier phase discriminator, a second carrier phase discriminator, a first sum module, a first difference module, a first carrier loop filter, a second carrier loop filter, and a carrier loop parameter prediction module;

[0110] The input end of the first carrier phase discriminator is connected to the integrated and accumulated results of the current code branch of the I path of the first frequency point and the integrated and accumulated results of the current code branch of the Q path of the first frequency point; the input end of the second carrier phase discriminator is connected to the integrated and accumulated results of the current code branch of the Q path of the second frequency point and the integrated and accumulated results of the current code branch of the Q path of the second frequency point;

[0111] The output ends of the first carrier phase discriminator and the second carrier phase discriminator are respectively connected to the two input ends of the first sum module and the first difference module;

[0112] The first sum module and the first difference module respectively carry out sum and difference processing on the phase discrimination results of the first carrier phase discriminator and the second carrier phase discriminator; the output ends respectively output the first sum result and the first difference result;

[0113] The input ends of the first carrier loop filter and the second carrier loop filter are respectively input with the first sum result and the first difference result; the filtered first sum result and the filtered first difference result output by the first carrier loop filter and the second carrier loop filter are input to the carrier loop parameter prediction module;

[0114] ​The carrier loop parameter prediction module predicts the carrier loop parameters of the first and second frequencies respectively and outputs to the recurring carrier modules of the first and second frequencies to control the carrier recurrence.

[0115] In the carrier loop parameter prediction module, the sum of the filtering results of the first and second carrier loop filters is taken as the carrier loop parameter of the first frequency, and the difference of the filtering results of the first and second carrier loop filters is taken as the carrier loop parameter of the first frequency.

[0116] Specifically, the dual-frequency signal code loop comprises a first code loop discriminator, a second code loop discriminator, a second sum module, a second difference module, a first code loop filter, a second code loop filter, a third sum module, a fourth sum module and a code loop parameter prediction module.

[0117] The input end of the first code loop discriminator is connected to the first frequency early and late path despread results, and the input end of the second code loop discriminator is connected to the second frequency early and late path despread results.

[0118] The output ends of the first and second code loop discriminators are respectively connected to the two input ends of the second sum module and the second difference module.

[0119] The second sum module and the second difference module respectively perform sum and difference processing on the discrimination results of the first and second code loop discriminators, and output the second sum result and the second difference result respectively.

[0120] The input ends of the first and second code loop filters are respectively connected to the second sum result and the second difference result, the output ends of the first and second code loop filters are respectively connected to the two input ends of the third sum module and the fourth sum module.

[0121] The second sum result filtered by the first code loop filter and the first sum result filtered by the first carrier loop filter are summed in the third sum module.

[0122] The second difference result filtered by the second code loop filter and the first difference result filtered by the second carrier loop filter are summed in the fourth sum module.

[0123] The output ends of the third and fourth sum modules are connected to the input end of the code loop parameter prediction module.

[0124] The code loop parameter prediction module predicts the code loop parameters for controlling the code phases of the first and second frequencies respectively and outputs to the code generators of the first and second frequencies to perform closed-loop tracking of the first and second frequency signal code loops.

[0125] Specifically, in the code loop parameter prediction module, the sum of the third and result and the fourth and result is taken as the code loop parameter of the first frequency point; and the difference between the third and result and the fourth and result is taken as the code loop parameter of the second frequency point.

[0126] Figure 3 Taking the baseband tracking processing of the common star L1 and L2 signals of GPS as an example, in the figure a sum module, a difference module.

[0127] More specifically, the first carrier loop filter and the second carrier loop filter are high-order large-bandwidth filters; and the third carrier loop filter and the fourth carrier loop filter are low-order narrow-bandwidth filters.

[0128] In the embodiment, the specific technical details and beneficial effects are the same as those described in the first embodiment, and please refer to the first embodiment for details, which will not be described here.

[0129] The above only describes the preferred embodiments of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A GNSS co-satellite dual-frequency signal baseband carrier / code joint tracking and processing method, characterized in that: include: Step S1: Use the constructed dual-frequency joint carrier tracking loop to perform closed-loop tracking of the dual-frequency carrier to reproduce the carrier of the dual-frequency signal; Among them, in the dual-frequency joint carrier tracking loop, the carrier phase detection results of the carrier tracking loops of the two frequency points are jointly used to predict the carrier loop parameters for controlling the carrier reproduction at each frequency point; Step S2: Using the constructed dual-frequency joint code tracking loop to perform closed-loop tracking of the dual-frequency signal code loop, and controlling the code phase of the code generator of the dual-frequency signal; The dual-frequency joint code tracking loop uses the code loop identification results of the code tracking loops of the two frequency points, combined with the carrier phase detection results of the dual-frequency joint carrier tracking loop, to predict the code loop parameters that control the code phase control of each frequency point. Step S3: Tracking the GNSS co-star dual-frequency signal through closed-loop tracking of the dual-frequency joint carrier tracking loop and the dual-frequency joint code tracking loop; In step S1, the closed-loop tracking process of the dual-frequency signal carrier loop includes: 1) performing sum and difference processing on a phase detection result of a first carrier phase detector in a first frequency carrier loop and a phase detection result of a second carrier phase detector in a second frequency carrier loop to obtain a first sum result and a first difference result; 2) outputting the first sum path result to a first carrier loop filter in a first frequency carrier loop for loop filtering; outputting the first difference path result to a second carrier loop filter in a second frequency carrier loop for loop filtering; 3) Predicting carrier loop parameters based on the filtering results output by the first carrier loop filter and the filtering results output by the second carrier loop filter to obtain carrier loop parameters for controlling the first and second frequency point recurring carriers; 4) using the carrier loop parameters of the first and second frequency point reproducing carriers to control the reproducing carrier frequencies in the first and second frequency point carrier loops respectively, and performing closed-loop tracking on the first and second frequency point signal carrier loops; In step S2, the closed-loop tracking process of the dual-frequency signal code loop includes: 1) performing difference and sum processing on a discrimination result of a first code loop discriminator in the first frequency code loop and a discrimination result of a second code loop discriminator in the second frequency code loop to obtain a second difference and sum result; 2) Outputting the second sum result to the first code loop filter for filtering, and then performing a sum operation with the filtered first sum result output by the first carrier loop filter to obtain a third sum result; outputting the second difference result to the second code loop filter for filtering, and then performing a sum operation with the filtered first difference result output by the second carrier loop filter to obtain a fourth sum result; 3) predicting code loop parameters based on the third and fourth summation results to predict code loop parameters for code phase control at the first and second frequency points; 4) Using the predicted code loop parameters for controlling the code phases of the first and second frequency points, the code phases of the code generators in the first and second frequency point code loops are controlled respectively, and closed-loop tracking of the first and second frequency point signal carrier loops is performed.

2. The GNSS co-satellite dual-frequency signal baseband carrier / code joint tracking processing method according to claim 1, characterized in that: In the carrier loop parameter prediction, the phase-locked values ​​of the first and second frequency carrier loops are restored; among them, the carrier loop parameter of the first frequency point reproduced carrier is the sum of the filtering results output by the first and second carrier loop filters; the carrier loop parameter of the second frequency point reproduced carrier is the difference between the filtering results output by the first and second carrier loop filters.

3. The GNSS co-satellite dual-frequency signal baseband carrier / code joint tracking processing method according to claim 1, characterized in that: In the code loop parameter prediction, the identification values ​​of the first and second frequency code loops are restored; among which, the code loop parameter of the first frequency point is the sum of the third and fourth summation results; the code loop parameter of the second frequency point is the difference between the third and fourth summation results.

4. The GNSS co-satellite dual-frequency signal baseband carrier / code joint tracking processing method according to any one of claims 1 to 3, characterized in that: The dual-frequency signal is any type of dual-frequency signal of a GNSS co-star and originating from a unified clock source.

5. The GNSS co-satellite dual-frequency signal baseband carrier / code joint tracking processing method according to claim 4, characterized in that: The first carrier loop filter and the first carrier loop filter are high-order and large-bandwidth filters; the second carrier loop filter and the second carrier loop filter are low-order and narrow-bandwidth filters.

6. A GNSS receiver, characterized in that: Carrier tracking and code tracking are performed using the common satellite dual-frequency signal baseband carrier / code joint tracking processing method according to any one of claims 1 to 5; comprising: a dual-frequency joint carrier tracking loop and a dual-frequency joint code tracking loop; The dual-frequency joint carrier tracking loop jointly utilizes the phase detection results of the carrier loops of the two frequency points to predict the carrier loop parameters of each frequency point, perform carrier recurrence control, and realize closed-loop tracking of the dual-frequency signal carrier loop; The dual-frequency joint code tracking loop jointly utilizes the phase detection results of the code tracking loops of the two frequency points, and combines the respective carrier loop filtering results in the dual-frequency joint carrier tracking loop to respectively predict the code loop parameters that control the code phase of each frequency point; performs code phase control to achieve closed-loop tracking of the dual-frequency signal code loop.

7. The GNSS receiver according to claim 6, characterized in that The dual-frequency signal carrier loop includes: a first carrier phase detector, a second carrier phase detector, a first sum path module, a first difference path module, a first carrier loop filter, a second carrier loop filter and a carrier loop parameter prediction module; Among them, the input end of the first carrier phase detector is connected to the integral and cumulative results of the current code branch of the first frequency point I and the integral and cumulative results of the current code branch of the Q road; the input end of the second carrier phase detector is connected to the integral and cumulative results of the current code branch of the second frequency point Q road and the integral and cumulative results of the current code branch of the Q road; The output ends of the first carrier phase detector and the second carrier phase detector are connected to the two input ends of the first sum path module and the first difference path module respectively; The first sum module and the first difference module respectively perform sum processing and difference processing on the phase detection results of the first carrier phase detector and the second carrier phase detector; the output ends respectively output the first sum result and the first difference result; The first sum path result and the first difference path result are input to the input ends of the first carrier loop filter and the second carrier loop filter respectively; the filtered first sum path result and the first difference path result output by the first carrier loop filter and the second carrier loop filter are input to the carrier loop parameter prediction module; The carrier loop parameter prediction module predicts the carrier loop parameters of the first and second frequency points respectively, and outputs them to the carrier reproducing modules of the first and second frequency points for controlling carrier reproducing.

8. The GNSS receiver according to claim 6, wherein: The dual-frequency signal code loop includes: a first code loop discriminator, a second code loop discriminator, a second summing path module, a second difference path module, a first code loop filter, a second code loop filter, a third summing path module, a fourth summing path module and a code loop parameter prediction module; The input end of the first code ring discriminator is connected to the despreading results of the leading path and the lagging path of the first frequency point; the input end of the second code ring discriminator is connected to the despreading results of the leading path and the lagging path of the second frequency point; The output ends of the first code ring discriminator and the second code ring discriminator are connected to the two input ends of the second sum path module and the second difference path module respectively; The second summation module and the second difference module respectively perform summation and difference processing on the identification results of the first code ring discriminator and the second code ring discriminator; the output ends respectively output the second summation result and the second difference result; The input ends of the first code loop filter and the second code loop filter are connected to the second summation result and the second difference result respectively; the output end of the first code loop filter and the output end of the first carrier loop filter are connected to the two input ends of the third summation module respectively; the output end of the second code loop filter and the output end of the second carrier loop filter are connected to the two input ends of the fourth summation module respectively; The second summation result after filtering by the first code loop filter and the first summation result after filtering by the first carrier loop filter are summed in a third summation module; The second difference path result after filtering by the second code loop filter and the first difference path result after filtering by the second carrier loop filter are summed in a fourth summing module; The output ends of the third and fourth summing modules are connected to the input end of the code loop parameter prediction module; The code loop parameter prediction module predicts the code loop parameters for controlling the code phase of the first and second frequency points respectively, and outputs them to the code generators of the first and second frequency points to perform closed-loop tracking of the code loops of the first and second frequency points signals.

Images