A discontinuous random time hopping pulse pseudolite signal tracking method based on carrier phase correction
By using a carrier phase correction method, the discontinuous random time-hopping pulse signal is compensated using receiver local information and phase-locked loop feedback value. This solves the problem of carrier frequency and pseudocode phase discontinuity in pseudo-satellite signal tracking, and achieves accurate tracking and performance improvement.
Patent Information
- Application Number
- CN202610880452.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-06-17
- Publication Date
- 2026-08-25
AI Technical Summary
In satellite navigation denied environments, the discontinuous random time-hopping pulses of pseudo-satellite signals prevent the receiver from accurately tracking the carrier signal frequency and pseudo-code phase, resulting in a degraded receiver performance.
By using the random time-hopping pulse position information generated locally by the receiver and the carrier Doppler estimate fed back by the back-end phase-locked loop, a carrier phase correction value is constructed. The intermediate frequency carrier phase is continuously compensated by sine/cosine rotation operation, and accurate tracking is achieved by combining pseudo-code delay-locked loop and carrier phase-locked loop.
It achieves accurate tracking of discontinuous random time-hopping pulse pseudo-satellite signals, obtains key parameters such as pseudo-code phase and carrier Doppler, and significantly improves the tracking performance of the receiver in low signal-to-noise ratio and dynamic environments.
Smart Images
Figure CN122632284A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a method for tracking discontinuous random time-hopping pulse pseudo-satellite signals based on carrier phase correction, belonging to the field of satellite navigation aid enhancement. In particular, it relates to a method that utilizes the random time-hopping pulse position information provided by the random time-hopping pulse generation and control module in the receiver, as well as the carrier Doppler information fed back by the back-end tracking, to construct a method for carrier phase correction of discontinuous pseudo-satellite signals converted to intermediate frequency, and then uses delay-locked loop and phase-locked loop to achieve accurate tracking of the corrected pseudo-satellite signals. Background Technology
[0002] In satellite navigation denied environments, such as inside large buildings, underground parking lots or shopping malls, and traffic tunnels, satellite navigation signals are severely attenuated or blocked, leading to a significant decrease in receiver performance or even loss of normal navigation and positioning functions. In these denied environments, deploying a number of pseudo-satellites that emit signals with a structure similar to satellite navigation signals can restore receiver performance. Furthermore, since these pseudo-satellites are typically installed on the ground (surface), and the user receiver is also located on the ground (surface), the distance between the pseudo-satellites and the receiver is much smaller than the distance between the navigation satellite and the receiver. This results in the receiver receiving much stronger pseudo-satellite signals than the normally received satellite navigation signals. Since satellite navigation receivers have a relatively small dynamic range when receiving satellite navigation signals, this leads to a severe "near-far" interference problem when receiving pseudo-satellite signals; that is, nearby pseudo-satellite signals suppress distant pseudo-satellite signals, as well as the still usable satellite navigation signals.
[0003] To address the aforementioned "near-far" interference problem, a common solution is to gate the continuous satellite navigation signals transmitted by pseudosatellites using random time-hopping pulses in different time slots. This transforms the signals into discontinuous random time-hopping pulse signals, effectively reducing or eliminating the impact of "near-far" interference. However, these discontinuous random time-hopping pulse signals also pose challenges to receiver signal reception. Specifically, due to the gating pulses, the carrier phase within different pulses becomes discontinuous. Consequently, the receiver cannot continuously adjust and update the carrier signal frequency during signal reception and tracking, ultimately failing to obtain accurate pseudocode phase and carrier Doppler parameters.
[0004] Based on the above analysis, it can be seen that exploring and discovering a method for correcting the carrier phase continuity within each effective time hop slot of a random time-hopping pulse pseudo-satellite is of great value and significance for enabling the receiver to accurately track the random time-hopping pulse signal and obtain key parameters such as pseudo-code phase and carrier Doppler, thereby ultimately realizing the use of pseudo-satellites to enhance satellite navigation performance in denial environments. Summary of the Invention
[0005] The purpose of this invention is to provide a method for tracking discontinuous random time-hopping pulse pseudo-satellite signals based on carrier phase correction, thus providing a new safeguard for achieving pseudo-satellite-assisted enhancement of satellite navigation performance.
[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: S1: At the signal receiving end, the received pseudo-satellite signal is down-converted to the intermediate frequency using the receiver's local oscillation signal; S2: Using the receiver's random time-hopping pulse generation and control module, the pseudo-satellite signal converted to intermediate frequency in step S1 is trunculated for effective time slot signals and the invalid time slot interference signals are removed; S3: Using the pulse position information provided by the random time-hopping pulse generation and control module, as well as the carrier Doppler information fed back from the back end, generate the carrier phase correction value within the effective time-hopping time slot after processing in step S2; S4: Further obtain the sine and cosine results of the carrier phase correction value in step S3, and use them to correct the instantaneous carrier phase value in the effective time slot obtained in step S2, so that the carrier phase in any two time slots is continuous. S5: Using a pseudocode delay-locked loop and a carrier phase-locked loop, the pseudo-satellite signal after carrier phase correction in step S4 is tracked, and the tracked pseudocode phase and carrier Doppler are fed back to the pulse generation and control module in step S2 and the carrier phase correction module in step S3, respectively, for the signal parameter adjustment of each module.
[0007] The method for down-converting the received pseudo-satellite signal to an intermediate frequency using the receiver's local oscillation signal in step S1 is as follows:
[0008] In the formula, To receive signals, where For signal power, , and These are respectively the pseudo-satellite data signal, pseudo-code signal, and random time-jump pulse signal. ,in and These represent the time slot width and frame period of the random time-hopping pulse, respectively. , The number of time slots contained in a time-hop frame. The period is represented as And in A rectangular pulse that takes a value of 1 within a certain range and a value of 0 in other ranges. for Multiples of, This indicates the floor function. and The first hop code stored in the time-hopping code table and the The time slot index of the time hop pulse in the time hop frame. , and All in Values within the range and ; This is the received signal after down-conversion to intermediate frequency; , and These are the transmit signal frequency, the receiver local oscillator frequency, and the received signal carrier Doppler frequency, respectively. The intermediate frequency of the down-conversion; and These are the initial phase of the received signal and the initial phase of the local oscillator, respectively. This is the initial phase after the down-transformation; and These are the received signal noise and the received signal noise after down-conversion to intermediate frequency, respectively. This indicates the result after low-pass filtering.
[0009] In step S2, the method for extracting effective time slot signals and removing invalid time slot interference signals from the pseudo-satellite signal converted to intermediate frequency using the receiver's random time-hopping pulse generation and control module is as follows:
[0010] In the formula, The time-hopping pulses are generated by the receiver's random time-hopping pulse generation and control module. for Compared to The initial phase difference, where for Multiples of, After signal synchronization , , .
[0011] The method for generating the carrier phase correction value within the effective time hop slot in step S3, using the pulse position information provided by the random time hop pulse generation and control module and the carrier Doppler information fed back from the back end, is as follows: , and
[0012] In the formula, This is to make the first Time jump frame and the previous one The signal carrier phase of the time-skipping frame is continuous and for the first Similarly, the carrier phase correction value applied to the signal in the time-hop frame, For the first The carrier phase correction value of the signal in the time-hop frame, and This indicates that the carrier phase of the signal tracking start frame will not be corrected; The carrier Doppler estimate fed back by the backend signal tracking module (when there is no feedback from the backend during the initial tracking phase). Set to 0).
[0013] In step S4, to ensure the carrier phase continuity between any two time slots, the method for correcting the instantaneous carrier phase within the effective time slot using the cosine and sine results of the generated carrier phase correction values is as follows:
[0014] In the formula, For the first The instantaneous value of the signal carrier phase after phase correction within the effective time slot of the time-hopping frame. and , This indicates that the phase value is taken.
[0015] In step S5, a pseudo-code delay-locked loop and a carrier phase-locked loop are used to track the pseudo-satellite signal after carrier phase correction, and the pseudo-code phase tracking value is obtained. and carrier Doppler tracking value The loop filters for the delay-locked loop and phase-locked loop can be third-order filters or Kalman filters, and the loop update can use a fixed frame period. Alternatively, a variable update cycle method with the same variation law as the time-jumping pulse can be used, while the tracking errors of the code phase and carrier Doppler are obtained by using a normalized incoherent lead-lag amplitude phase detector and a two-quadrant arctangent phase detector, respectively: ,
[0016] In the formula, For pseudocode chip width; To delay the spacing between the E and L correlators in the locked loop, ; , and The correlators for branches E, P, and L are respectively located at the 1st... The integral result within a valid jump time slot, and , and The results are similar to those of the Q branch.
[0017] The beneficial effects of this invention are as follows: This invention utilizes the location information of randomly hopping pulses generated locally by the receiver (i.e., the timing relationship of each effective time slot), and combines it with the carrier Doppler estimation value fed back by the back-end phase-locked loop, to construct a dedicated carrier phase correction value for each effective time hopping time slot. Then, through sine / cosine rotation operations, the intermediate frequency carrier phase of the received signal within that time slot is continuously compensated, so that the corrected signal exhibits a naturally continuous carrier phase between any two effective time slots. Based on this, the discontinuous pulse signal after phase correction can be equivalently represented as a continuous signal, and standard pseudocode delay-locked loops and carrier phase-locked loops can be directly used for accurate tracking, ultimately stably obtaining key parameters such as pseudocode phase and carrier Doppler. Using the carrier phase correction-based discontinuous random time-hopping pulse pseudo-satellite signal tracking method provided by this invention, the parameter performance obtained when tracking pseudo-satellite signals is superior to that of existing conventional loops without carrier phase correction and variable update cycle loops based on Kalman filtering. Therefore, the given method is more suitable for widespread application in situations where random time-hopping pulse pseudo-satellites are used to enhance satellite navigation performance. Attached Figure Description
[0018] Figure 1 This is a schematic diagram of the implementation principle of the discontinuous random time-hopping pulse pseudo-satellite signal tracking based on carrier phase correction designed by the present invention.
[0019] Figure 2 When there is no carrier phase correction, the conventional loop provides pseudo-satellite pseudo-code phase for different signal-to-noise ratios (SNR). ) and carrier Doppler ( Tracking results ( The default value is 0. (Default is 150Hz).
[0020] Figure 3 After correcting the carrier phase using the method provided in this invention, the conventional loop can handle pseudo-satellites under different SNRs. and Tracking results ( The default value is 0. (Default is 150Hz).
[0021] Figure 4 When there is no carrier phase correction, the variable update cycle loop based on Kalman filtering is used for pseudo-satellites under different SNRs. and Tracking results ( The default value is 0. (Default is 150Hz).
[0022] Figure 5This invention utilizes the method provided in this invention to correct the carrier phase, and then employs a Kalman filter-based variable update cycle loop to analyze pseudo-satellites under different SNRs. and Tracking results ( The default value is 0. (Default is 150Hz).
[0023] Figure 6 When there is no carrier phase correction, the conventional loop handles pseudo-satellites under different SNRs. and Tracking results ( The default value is 0. Preset button change).
[0024] Figure 7 After correcting the carrier phase using the method provided in this invention, the conventional loop can handle pseudo-satellites under different SNRs. and Tracking results ( The default value is 0. Preset button change).
[0025] Figure 8 When there is no carrier phase correction, the variable update cycle loop based on Kalman filtering is used for pseudo-satellites under different SNRs. and Tracking results ( The default value is 0. Preset button change).
[0026] Figure 9 This invention utilizes the method provided in this invention to correct the carrier phase, and then employs a Kalman filter-based variable update cycle loop to analyze pseudo-satellites under different SNRs. and Tracking results ( The default value is 0. Preset button change).
[0027] Figure 10 When there is no carrier phase correction, the conventional loop supports pseudo-satellites under different SNRs. and Tracking results ( The default value is 0. Preset button change).
[0028] Figure 11 After correcting the carrier phase using the method provided in this invention, the conventional loop can handle pseudo-satellites under different SNRs. and Tracking results ( The default value is 0. Preset button change).
[0029] Figure 12 When there is no carrier phase correction, the variable update cycle loop based on Kalman filtering is used for pseudo-satellites under different SNRs. and Tracking results ( The default value is 0. Preset button change).
[0030] Figure 13 This invention utilizes the method provided in this invention to correct the carrier phase, and then employs a Kalman filter-based variable update cycle loop to analyze pseudo-satellites under different SNRs. and Tracking results ( The default value is 0. Preset button change). Detailed Implementation
[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. Of course, the specific embodiments described herein are merely illustrative and not intended to limit the invention.
[0032] The technical concept of this invention is as follows: Addressing the technical challenge of discontinuous carrier phases between different time-hop frames caused by gating pulses in random time-hop pulse pseudo-satellite signals, which renders traditional continuous tracking loops unsuitable, this invention proposes a tracking approach based on active carrier phase correction. The core of this concept is: utilizing the location information of randomly hop pulses generated locally by the receiver (i.e., the timing relationship of each effective time slot), and combining it with the carrier Doppler estimation value fed back by the back-end phase-locked loop, a dedicated carrier phase correction value is constructed for each effective time-hop slot; then, through sine / cosine rotation operations, the intermediate frequency carrier phase of the received signal within that time slot is continuously compensated, ensuring that the corrected signal exhibits a naturally continuous carrier phase between any two effective time slots. Based on this, the discontinuous pulse signal after phase correction can be equivalently represented as a continuous signal, allowing for precise tracking using standard pseudo-code delay-locked loops and carrier phase-locked loops, ultimately stably acquiring key parameters such as pseudo-code phase and carrier Doppler. Unlike existing technologies that directly perform Kalman filtering prediction on discontinuous signals or abandon carrier phase tracking, this concept fundamentally eliminates the tracking obstacle introduced by time-hopping pulses by actively correcting phase discontinuities, significantly improving the receiver's tracking performance in low signal-to-noise ratio and dynamic environments.
[0033] Reference Figure 1 The diagram shown illustrates a principle of a discontinuous random time-hopping pulse pseudo-satellite signal tracking method based on carrier phase correction, which includes the following specific steps: S1: At the signal receiving end, the received pseudo-satellite signal is down-converted to the intermediate frequency (IF) using the receiver's local oscillator signal. The method for down-converting the received pseudo-satellite signal to the IF using the receiver's local oscillator signal is as follows: (1) In the formula, To receive signals, where For signal power, , and These are respectively the pseudo-satellite data signal, pseudo-code signal, and random time-jump pulse signal. ,in and These represent the time slot width and frame period of the random time-hopping pulse, respectively. , The number of time slots contained in a time-hop frame. The period is represented as And in A rectangular pulse that takes a value of 1 within a certain range and a value of 0 in other ranges. for Multiples of, This indicates the floor function. and The first hop code stored in the time-hopping code table and the The time slot index of the time hop pulse in the time hop frame. , and All in Values within the range and ; This is the received signal after down-conversion to intermediate frequency; , and These are the transmit signal frequency, the receiver local oscillator frequency, and the received signal carrier Doppler frequency, respectively. The intermediate frequency of the down-conversion; and These are the initial phase of the received signal and the initial phase of the local oscillator, respectively. This is the initial phase after the down-transformation; and These are the received signal noise and the received signal noise after down-conversion to intermediate frequency, respectively. This indicates the result after low-pass filtering.
[0034] S2: Using the random time-hopping pulse generation and control module in the receiver, the effective time-slot signal of the pseudo-satellite signal converted to the intermediate frequency in step S1 is truncated, and the invalid time-slot interference signal is removed. The method for truncating the effective time-slot signal and removing the invalid time-slot interference signal from the pseudo-satellite signal converted to the intermediate frequency is as follows: (2) In the formula, The time-hopping pulses are generated by the receiver's random time-hopping pulse generation and control module. for Compared to The initial phase difference, where for Multiples of, After signal synchronization , , .
[0035] S3: Using the pulse position information provided by the random time-hopping pulse generation and control module, and the carrier Doppler information fed back from the back end, generate the carrier phase correction value within the effective time-hopping slot after processing in step S2. The method for generating the carrier phase correction value within the effective time-hopping slot is as follows: , and (3) In the formula, This is to make the first Time jump frame and the previous one The signal carrier phase of the time-skipping frame is continuous and for the first Similarly, the carrier phase correction value applied to the signal in the time-hop frame, For the first The carrier phase correction value of the signal in the time-hop frame, and This indicates that the carrier phase of the signal tracking start frame will not be corrected; The carrier Doppler estimate fed back by the backend signal tracking module (when there is no feedback from the backend during the initial tracking phase). Set to 0).
[0036] S4: Further obtain the sine and cosine results of the carrier phase correction value from step S3, and use them to correct the instantaneous carrier phase value within the effective time slot obtained in step S2, so that the carrier phase is continuous between any two time slots. The method for correcting the instantaneous carrier phase within the effective time slot is as follows: (4) In the formula, For the first The instantaneous value of the signal carrier phase after phase correction within the effective time slot of the time-hopping frame. and , This indicates that the phase value is taken.
[0037] S5: Using a pseudocode delay-locked loop (DLL) and a carrier phase-locked loop (PLL), the pseudo-satellite signal after carrier phase correction in step S4 is tracked. The tracked pseudocode phase and carrier Doppler are fed back to the pulse generation and control module in step S2 and the carrier phase correction module in step S3, respectively, for signal parameter adjustment in each module. The loop filters for the DLL and PLL can be third-order filters or Kalman filters, and the loop update can use a fixed frame period. Alternatively, a variable update cycle method with the same variation law as the time-jumping pulse can be used, while the tracking errors of the code phase and carrier Doppler are obtained by using a normalized incoherent lead-lag amplitude phase detector and a two-quadrant arctangent phase detector, respectively: , (5) In the formula, For pseudocode chip width; To delay the spacing between the E and L correlators in the locked loop, ; , and The correlators for branches E, P, and L are respectively located at the 1st... The integral result within a valid jump time slot, and , and The results are similar to those of the Q branch.
[0038] Using the carrier phase correction-based discontinuous random time-hopping pulse pseudo-satellite signal tracking method given above, the tracking performance of a fixed update period conventional loop based on a third-order filter (hereinafter referred to as Con-FURL) and a variable update period loop based on a Kalman filter (hereinafter referred to as KF-VURL) were examined in two cases: with and without carrier phase correction. The performance of the third-order filter was... s The domain transfer function is ,here a and b Typical values of 1.1 and 2.4 can be used accordingly. For loop gain, characteristic frequency By noise bandwidth This is confirmed, and the Kalman filter can be found in relevant literature.
[0039] According to the implementation process of the given method, the carrier Doppler is first applied. At a fixed frequency of 150Hz, the tracking performance of conventional Con-FURL loops and KF-VURL loops was examined under both carrier phase correction and carrier phase correction conditions. The results are as follows: Figures 2-5 As shown. Then, carrier Doppler... It changes according to the frequency gradient, that is , The tracking performance of conventional Con-FURL loops and KF-VURL loops was examined under both carrier phase correction and carrier phase correction conditions. The results are as follows: Figures 6-9 As shown. Finally, further analysis of carrier Doppler... According to the frequency acceleration method, that is , The tracking performance of conventional Con-FURL loops and KF-VURL loops was examined under both carrier phase correction and carrier phase correction conditions. The results are as follows: Figures 10-13 As shown. During the testing of the different schemes described above, the pseudocode phase... Since each valid pulse time slot typically contains a complete pseudocode period, therefore It is always continuous, meaning no phase continuity correction is needed. With this in mind, during tracking tests, it is always... The default value is 0.
[0040] The test results show that the random time-hopping pulse pseudo-satellite tracking method based on carrier phase correction proposed in this patent has advantages over existing methods such as Con-FURL and KF-VURL, which are used for pseudo-satellite signal tracking but lack carrier phase correction. These advantages are mainly reflected in the following aspects: (1) This patent provides a new pseudo-satellite signal tracking method by continuously correcting the carrier phase. Thus, when using the same third-order filter and fixed update period, for the same signal-to-noise ratio (SNR), the proposed method can quickly and accurately track the pseudo-satellite signal and obtain key parameters compared to the conventional Con-FURL method without carrier phase correction. and The value. This varies depending on the different schemes. Figure 2 and Figure 3 , Figure 6 and Figure 7 ,as well as Figure 10 and Figure 11 The comparison results clearly show this.
[0041] (2) Regarding the new pseudo-satellite signal tracking method provided in this patent, when using the same Kalman filter and variable update period, for the same SNR condition, the given method can also quickly and accurately track pseudo-satellite signals and obtain key parameters compared to the KF-VURL method without carrier phase correction. and The value. And this varies depending on the different schemes. Figure 4 and Figure 5 , Figure 8 and Figure 9 ,as well as Figure 12 and Figure 13 This can also be clearly seen in the comparison.
[0042] Therefore, under the same conditions, the pseudo-satellite signal tracking method based on carrier phase correction provided in this patent is significantly superior to the existing Con-FURL and KF-VURL methods without carrier phase correction. The following will provide a detailed explanation of these results based on specific implementation schemes.
[0043] Specific methods and results for different situations I. Implementation Method and Results of Pseudo-Satellite Signal Tracking Based on Carrier Phase Correction when Doppler Frequency is Fixed In this implementation, the performance of tracking random time-hopping pulse pseudosatellite signals with a fixed Doppler frequency using the given method was primarily examined. The examination was conducted based on the proposed Con-FURL and KF-VURL methods. Specifically, the examination method involved setting different SNRs and testing the performance of the two methods with and without carrier phase correction, focusing on key parameters. and The tracking and acquisition status. During testing. The preset frequency is 150Hz, the time-hopping pulse duty cycle is set to 0.1, the time-hopping frame period is set to one GPS C / A code period (1ms), the signal tracking duration is set to 3s, and the noise bandwidths of the phase-locked loop (PLL) and delay-locked loop (LDL) are set to 10Hz and 0.8Hz, respectively. Using these parameters, combined with... Figure 1 Following steps S1 to S5 above, we can obtain the tracking results of the conventional Con-FURL method with and without carrier phase correction when the SNR is -10dB and -5dB, respectively. Figure 2 and 3 As shown; similarly, when other conditions remain unchanged but the tracing method is changed to KF-VURL, the following can be obtained: Figure 4 and 5 The result.
[0044] contrast Figure 2 and 3It can be seen that without continuity correction of the carrier phase, the phase-locked loop of the conventional Con-FURL method will be unable to correctly track the carrier phase and provide the correct output. The parameters, and the delay-locked loop that tracks the pseudocode phase, will eventually lose lock due to the influence of the phase-locked loop, and thus also cannot obtain the parameters. The result; however, when the carrier phase is corrected using the method provided in the patent, both the phase-locked loop and the delay-locked loop can accurately track the signal and provide the correct output. and Parameters. For the KF-VURL method, from Figure 4 and 5 The comparison also shows that before carrier phase correction, the signal could not be tracked correctly, but after using the method provided in the patent to correct the carrier phase, the signal could be tracked accurately and the correct signal could be obtained. and Parameter results.
[0045] II. Implementation Method and Results of Pseudosatellite Signal Tracking Based on Carrier Phase Correction During Doppler Frequency Rise In this implementation, the performance of tracking random time-hopping pulse pseudosatellite signals during Doppler frequency ramp-up using the given method was primarily examined. The examination was conducted using both Con-FURL and KF-VURL methods. The specific examination method is the same as in Implementation Scheme 1 above. Regarding parameter settings, except... according to Besides the change in the upward slope, here Other parameter settings are the same as in Implementation Scheme 1 above. Using these parameters, combined with... Figure 1 Following steps S1 to S5 above, we can obtain the tracking results of the conventional Con-FURL method with and without carrier phase correction when the SNR is -10dB and -5dB, respectively. Figure 6 and 7 As shown; similarly, when other conditions remain unchanged but the tracing method is changed to KF-VURL, the following can be obtained: Figure 8 and Figure 9 The result.
[0046] contrast Figure 5 and 6 It can be seen that, without continuous correction of the carrier phase, the conventional Con-FURL method cannot correctly track the carrier phase and provide a signal when the Doppler frequency changes in a frequency ramp manner. Parameters, and the delayed locking ring can also be affected by the phase-locked loop and lose lock, ultimately failing to obtain the correct parameters. Parameters; however, when the carrier phase is continuously corrected using the method provided in the patent, both the phase-locked loop and the delay-locked loop can accurately track the signal and provide correct parameters. and Parameters. For the KF-VURL method, from Figure 8 and Figure 9 The comparison also shows that before carrier phase correction, the signal could not be tracked correctly, but after the given method was used to correct the carrier phase, the signal could be tracked accurately and the correct signal could be obtained. and Parameter results.
[0047] III. Implementation Method and Results of Pseudo-Satellite Signal Tracking Based on Carrier Phase Correction During Doppler Frequency Acceleration In this embodiment, the performance of the given method in tracking random time-hopping pulse pseudo-satellite signals during Doppler frequency acceleration was further examined. The examination was also conducted using both Con-FURL and KF-VURL methods, and the examination method was the same as in Implementation Scheme 1 above. Regarding parameter settings, except... according to Besides the change in acceleration method, here Other parameter settings are the same as in Implementation Scheme 1 above. Using these parameters, combined with... Figure 1 Following steps S1 to S5 above, we can obtain the tracking results of the conventional Con-FURL method with and without carrier phase correction when the SNR is -10dB and -5dB, respectively. Figure 10 and Figure 11 As shown; similarly, when other conditions remain unchanged but the tracing method is changed to KF-VURL, the following can be obtained: Figure 12 and Figure 13 The result.
[0048] contrast Figure 10 and Figure 11 It can be seen that, without continuous correction of the carrier phase, the conventional Con-FURL method's phase-locked loop also fails to correctly track the carrier phase and provide a signal when the Doppler frequency changes in a frequency-accelerated manner. The parameters, and the delayed locking ring will also be affected and cannot be obtained correctly. Parameters. When the carrier phase is corrected using the method provided in the patent, both the phase-locked loop (PLL) and the delay-locked loop (DLL) can accurately track the signal and obtain the correct parameters. and Parameter results. For the KF-VURL method, from Figure 12 and Figure 13 Similar results to the Con-FURL method can be obtained in the comparison. All these results fully demonstrate the superiority of the method provided in the patent.
[0049] The present invention has been described above by way of example with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvements made using the inventive concept and technical solution of the present invention, or the direct application of the inventive concept and technical solution of the present invention to other occasions without modification, are all within the protection scope of the present invention.
Claims
1. A method for tracking discontinuous random time-hopping pulse pseudo-satellite signals based on carrier phase correction, characterized in that, Includes the following steps: S1: At the signal receiving end, the received pseudo-satellite signal is down-converted to the intermediate frequency using the receiver's local oscillation signal; S2: Using the random time-hopping pulse generation and control module in the receiver, the effective time slot signal is extracted and the invalid time slot interference signal is removed from the pseudo-satellite signal converted to the intermediate frequency. S3: Using the pulse position information provided by the random time-hopping pulse generation and control module, as well as the carrier Doppler information fed back from the back end, generate the carrier phase correction value within the effective time-hopping slot; S4: Use the carrier phase correction value to obtain its sine and cosine results, and use the obtained sine and cosine results to correct the instantaneous value of the carrier phase in the effective time slot so that the carrier phase in any two time slots is continuous; S5: Using a pseudocode delay-locked loop and a carrier phase-locked loop, the pseudo-satellite signal after carrier phase correction is tracked, and the tracked pseudocode phase and carrier Doppler are fed back to the front-end pulse generation and control module and the carrier phase correction module, respectively, for the signal parameter adjustment of each module.
2. The method for tracking discontinuous random time-hopping pulse pseudo-satellite signals based on carrier phase correction according to claim 1, characterized in that, The method for down-converting the received pseudo-satellite signal to an intermediate frequency using the receiver's local oscillation signal in step S1 is as follows: In the formula, This is the received signal after down-conversion to intermediate frequency; To receive signals; For signal power, , and These are respectively the pseudo-satellite data signal, pseudo-code signal, and random time-jumping pulse signal; ,in and These represent the time slot width and frame period of the random time-hopping pulse, respectively. , The number of time slots contained in a time-hop frame. The period is represented as And in A rectangular pulse that takes a value of 1 within a certain range and a value of 0 in other ranges. for Multiples of, This indicates the floor function. and The first one stored in the time-hopping code table is the second one. and the The time slot index of the time hop pulse in the time hop frame. , and All in Values within the range and ; , and These are the transmitted signal frequency, the receiver local oscillator frequency, and the received signal carrier Doppler frequency, respectively. The intermediate frequency of the down-conversion; and These are the initial phase of the received signal and the initial phase of the local oscillator, respectively. This is the initial phase after the down-transformation; and These are the received signal noise and the received signal noise after down-conversion to intermediate frequency, respectively. This indicates the result after low-pass filtering.
3. The method for tracking discontinuous random time-hopping pulse pseudo-satellite signals based on carrier phase correction according to claim 1, characterized in that, In step S2, the method for extracting effective time slot signals and removing invalid time slot interference signals from the pseudo-satellite signal converted to intermediate frequency using the receiver's random time-hopping pulse generation and control module is as follows: In the formula, The time-hopping pulses are generated by the receiver's random time-hopping pulse generation and control module. for Compared to The initial phase difference, where for Multiples of, After signal synchronization , , .
4. The method for tracking discontinuous random time-hopping pulse pseudo-satellite signals based on carrier phase correction according to claim 1, characterized in that, The method for generating the carrier phase correction value within the effective time hop slot in step S3, using the pulse position information provided by the random time hop pulse generation and control module and the carrier Doppler information fed back from the back end, is as follows: , and In the formula, This is to make the first Time jump frame and the previous one The signal carrier phase of the time-skipping frame is continuous and for the first The carrier phase correction value applied to the signal in the time-skipped frame. For the first The carrier phase correction value of the signal in the time-hop frame, and This indicates that the carrier phase of the signal tracking start frame will not be corrected; This is the carrier Doppler estimate fed back by the backend signal tracking module. During the initial tracking phase, when there is no feedback from the backend... Set it to 0.
5. The method for tracking discontinuous random time-hopping pulse pseudo-satellite signals based on carrier phase correction according to claim 1, characterized in that, In step S4, to ensure the carrier phase continuity between any two time slots, the instantaneous carrier phase value within the effective time slot is corrected using the sine and cosine results of the generated carrier phase correction value. In the formula, For the first The instantaneous value of the signal carrier phase after phase correction within the effective time slot of the time-hopping frame. and , This indicates that the phase value is taken.
6. The method for tracking discontinuous random time-hopping pulse pseudo-satellite signals based on carrier phase correction according to claim 1, characterized in that, In step S5, a pseudo-code delay-locked loop and a carrier phase-locked loop are used to track the pseudo-satellite signal after carrier phase correction, and the pseudo-code phase tracking value is obtained. and carrier Doppler tracking value Loop updates use a fixed frame period Alternatively, a variable update cycle method with the same time-jump pulse variation pattern can be used, while the tracking errors of the code phase and carrier Doppler are obtained using a normalized incoherent lead-lag amplitude phase detector and a two-quadrant arctangent phase detector, respectively. ， In the formula, For pseudo-code chip width; To delay the spacing between the E and L correlators in the locked loop, ; , and The correlators for branches E, P, and L are respectively located at the 1st... The integral result within a valid jump time slot, and , and Then, the correlators E, P, and L in the Q branch are respectively in the th... The integral result within each valid jump time slot.
7. The method for tracking discontinuous random time-hopping pulse pseudo-satellite signals based on carrier phase correction according to claim 6, characterized in that, The loop filters for the delay-locked loop and phase-locked loop are selected as third-order filters or Kalman filters.
8. The method for tracking discontinuous random time-hopping pulse pseudo-satellite signals based on carrier phase correction according to claim 1, characterized in that, The random time-hopping pulse signal adopts a non-full time-slot duty cycle, and its frame period is an integer multiple of the pseudocode period of the pseudo-satellite signal.
9. The method for tracking discontinuous random time-hopping pulse pseudo-satellite signals based on carrier phase correction according to claim 6, characterized in that, The noise bandwidth of the phase-locked loop and the delay-locked loop is configured according to a preset dynamic environment, wherein the noise bandwidth of the delay-locked loop is lower than that of the phase-locked loop.