Adaptive tracking method and system based on code ring and carrier ring deep cooperation

Abstract

The application relates to a code ring and carrier ring deep cooperation-based adaptive tracking method and system and belongs to the technical field of signal tracking. The method comprises the following steps: a code ring and carrier ring deep cooperation-based tracking loop is constructed; when encountering a weak signal / strong interference environment, the normal carrier ring assists code ring mode switching to code ring assists carrier ring mode; at this time, code frequency and pseudo-range information output by the code ring are injected into the carrier ring as prior information, so that the carrier ring does not need to search the carrier frequency in a large range; meanwhile, a pre-stored channel fixed deviation is introduced to perform ionospheric delay compensation on the carrier phase; a more accurate carrier frequency deviation can be estimated according to the deviation between the ionospheric-compensated carrier phase and the current carrier phase, the carrier ring is quickly recovered to be locked, and therefore, the dynamic tracking capability and the anti-interference performance of the carrier ring are improved without increasing the hardware complexity, and the positioning availability of the receiver is improved.

Description

Technical Field

[0001] This application relates to the field of signal tracking technology, and in particular to an adaptive tracking method and system based on deep collaboration between code ring and carrier ring. Background Technology

[0002] With the expanding application of satellite navigation systems such as BeiDou and GPS in complex environments (such as urban streets, indoors, canyons, and electromagnetic interference), the tracking performance of receivers has become a research hotspot. In such environments, the received signal strength is weak, the carrier-to-noise ratio is low, the Doppler variation is drastic, and the interference power is strong, which can easily lead to problems such as signal tracking loss, decreased positioning accuracy, or even inability to locate.

[0003] In GNSS (Global Navigation Satellite System) receivers, the performance of the carrier loop and code loop tracking loop directly determines the tracking capability under weak signal conditions. Traditional receivers use independent carrier loops and code loops for signal tracking, or use a carrier loop to assist the code loop for signal tracking. They perform well in the absence of interference, but in strong interference environments, the carrier loop has large frequency / phase discrimination errors and is easily biased by interference, leading to deterioration of tracking accuracy, increased loop jitter, and prolonged lock-on time, which seriously affects the receiver performance. Summary of the Invention

[0004] Therefore, it is necessary to provide an adaptive tracking method and system based on deep collaboration between the code ring and the carrier ring to address the technical problems of poor tracking stability and easy loss of lock in traditional carrier rings under low carrier-to-noise ratio and interference environments.

[0005] An adaptive tracking method based on deep coordination of code ring and carrier ring, the method comprising: The receiver's environmental status during signal tracking is monitored in real time. When it is determined that the current environment is weak signal / strong interference, the receiver's tracking loop route is switched from the normal carrier loop-assisted code loop mode to the code loop-assisted carrier loop mode. At the same time, the channel fixed deviation between the two loops caused by ionospheric delay during the switching is stored. In code-ring-assisted carrier-ring mode, the code frequency and pseudorange information output in real time by the code ring are injected into the carrier ring as prior information. The carrier Doppler auxiliary frequency is calculated based on the code frequency. The carrier phase after ionospheric compensation is reconstructed based on the pseudorange information and the fixed channel deviation. The frequency correction is calculated based on the deviation between the carrier phase after ionospheric compensation and the current carrier phase. Finally, the carrier Doppler auxiliary frequency and the frequency correction are combined to help the carrier ring quickly recover lock and optimize the stable tracking of the carrier ring in weak signal / strong interference environment.

[0006] In one embodiment, calculating the carrier Doppler auxiliary frequency based on the code frequency includes: The code frequency output by the code ring in code ring assisted carrier ring mode is stable. Converted proportionally to carrier-Doppler auxiliary frequency , is represented as: ; in, For the signal carrier frequency, For pseudocode rate; carrier Doppler auxiliary frequency Used as a feedforward injection into the frequency control terminal of the carrier NCO responsible for generating the local carrier in the carrier loop, it offsets most of the dynamic stress, ensuring that the carrier NCO frequency quickly approaches the true value.

[0007] In one embodiment, the ionospherically compensated carrier phase is reconstructed based on pseudorange information and channel fixed deviation, and a frequency correction is calculated based on the deviation between the ionospherically compensated carrier phase and the current carrier phase. Finally, the carrier Doppler-assisted frequency and the frequency correction are combined to assist the carrier loop in rapid recovery of lock, including: Real-time acquisition of code ring pseudorange observations in code ring-assisted carrier ring mode and combined with channel fixed deviation Reconstructed carrier phase prediction after ionospheric compensation , is represented as: ; in, The carrier wavelength; The deviation between the ionospherically compensated carrier phase prediction and the carrier NCO phase is converted into a frequency correction value. and frequency correction amount With carrier Doppler auxiliary frequency After being superimposed, they jointly drive the carrier NCO to assist the carrier loop in quickly restoring lock.

[0008] In one embodiment, the channel fixed deviation is calculated and stored in real time in carrier loop-assisted code loop mode, and the calculation stops when the tracking loop switches to code loop-assisted carrier loop mode; the channel fixed deviation The expression is: ; in, This is the weighting coefficient, with a value close to 1; For code ring pseudorange observations and The difference, These are carrier phase observations.

[0009] In one embodiment, the rule for determining whether the receiver's tracking loop routing carrier ring-assisted code ring mode is switched to code ring-assisted carrier ring mode is as follows: By monitoring the phase error of the carrier loop output in real time during signal tracking, the carrier loop lock indication value is calculated and combined with the current carrier-to-noise ratio of the signal to detect the environmental status. When the carrier loop lock indicator value meets the condition of being higher than the preset first confidence threshold, the carrier-to-noise ratio meets the condition of being higher than the preset rise threshold, and the duration of both conditions being met exceeds the first preset duration, it is determined that the current environment is a strong signal environment. At this time, the tracking loop maintains the normal carrier loop auxiliary code loop mode. When the carrier loop lock indicator value is lower than the preset second confidence threshold, the carrier-to-noise ratio is lower than the preset descent threshold, and both conditions are met for a duration exceeding the second preset duration, the current environment is determined to be a weak signal / strong interference environment, and the tracking loop switches to code loop assisted carrier loop mode; wherein, the preset first confidence threshold is greater than the preset second confidence threshold, the preset rise threshold is greater than the preset fall threshold, and the first preset duration is greater than the second preset duration; The two modes adaptively switch based on real-time environmental conditions to maintain continuous and robust signal tracking.

[0010] In one embodiment, the carrier loop lock indication value is calculated by real-time monitoring of the phase error output of the carrier loop during signal tracking, including: The operating status of the carrier loop and code loop is monitored in real time during signal tracking. The absolute value of the phase error output by the carrier loop is taken and then filtered by a first-order low-pass filter to obtain the average phase jitter estimate. and will Mapped to carrier loop lock indicator value , is represented as: ; in, This is the preset carrier ring lockout threshold.

[0011] In one embodiment, the tracking loop includes a signal forward path, a code loop module, and a carrier loop module; The forward path of the signal includes an I / Q mixer and an I / Q correlator. The I / Q mixer receives the input signal and multiplies it with the local carrier generated by the carrier loop module to complete carrier stripping and obtain the baseband signal. The I / Q correlator is equipped with three branches: lead, instant, and lag. Each branch is used to receive the baseband signal output by the I / Q mixer and perform correlation integration with the local pseudocode generated by the code loop module to output the integration result. The code ring module adopts a second-order delay-locked loop structure, including a code ring discriminator, a code ring filter, a C / A code NCO, and a C / A code generator. The code ring discriminator is connected to the output terminals of the lead and lag branches of the I / Q correlator. It uses an incoherent lead-lag amplitude method to compare the amplitude difference between the lead and lag branches to extract the output code phase error. The code phase error is filtered by the code ring filter and used as the control input of the C / A code NCO to adjust the frequency and phase of the local pseudo code output by the C / A code generator. The local pseudo code generated by the C / A code generator is then injected into the I / Q correlator. The carrier loop module adopts a phase-locked loop structure, which includes a carrier loop discriminator, a carrier loop filter, and a carrier NCO. The carrier loop discriminator is connected to the output of the instantaneous branch of the I / Q correlator to obtain the integral result of the instantaneous branch. It uses a two-quadrant arctangent phase detector to extract the output phase error. After the phase error is filtered by the carrier loop filter, it drives the carrier NCO to adjust the local carrier frequency. The carrier NCO generates a sine / cosine local carrier and injects it into the I / Q mixer.

[0012] In one embodiment, when the tracking loop maintains a normal carrier loop-assisted code loop mode, the output of the carrier loop filter is also jointly input with the output of the code loop filter to the C / A code NCO to assist the C / A code generator in adjusting the phase and rate of the local pseudo-code.

[0013] In one embodiment, when the tracking loop switches to code-ring-assisted carrier-ring mode, the output of the carrier-ring filter is directly discarded, while the code frequency and pseudorange information output by the code-ring filter are injected into the carrier-ring as prior information. The carrier Doppler-assisted frequency is calculated based on the code frequency, and the carrier phase after ionospheric compensation is reconstructed based on the pseudorange information and the stored channel fixed deviation. The frequency correction is calculated based on the deviation between the ionospherically compensated carrier phase and the current carrier phase. Finally, the carrier Doppler-assisted frequency and the frequency correction are input to the carrier NCO to assist the carrier NCO in adjusting the phase and rate of the local carrier, thereby quickly restoring lock.

[0014] An adaptive tracking system based on deep coordination of code ring and carrier ring, the system comprising: The first unit is used to monitor the environmental status of the receiver in real time during the signal tracking process. When it is determined that the current environment is a weak signal / strong interference environment, the tracking loop route of the receiver is switched from the normal carrier loop assisted code loop mode to the code loop assisted carrier loop mode. At the same time, the channel fixed deviation caused by ionospheric delay between the two loops during the switching is stored. The second unit is used in code ring-assisted carrier ring mode to inject the code frequency and pseudorange information output by the code ring in real time as prior information into the carrier ring, calculate the carrier Doppler auxiliary frequency based on the code frequency, reconstruct the carrier phase after ionospheric compensation based on the pseudorange information and the fixed channel deviation, and calculate the frequency correction amount according to the deviation between the carrier phase after ionospheric compensation and the current carrier phase. Finally, the carrier Doppler auxiliary frequency and the frequency correction amount are combined to assist the carrier ring in quickly restoring lock and optimize the stable tracking of the carrier ring in weak signal / strong interference environment.

[0015] The aforementioned adaptive tracking method and system based on deep collaboration between the code ring and carrier ring addresses the problems of traditional carrier rings being prone to lock-out and slow reacquisition in low carrier-to-noise ratio and strong interference scenarios. It constructs a tracking loop with deep collaboration between the code ring and carrier ring. This loop can switch from a normal carrier ring-assisted code ring mode to a code ring-assisted carrier ring mode when encountering weak signal / strong interference environments. In the code ring-assisted carrier ring mode, the code frequency and pseudorange information output by the code ring are injected into the carrier ring as prior information, eliminating the need for searching the carrier frequency over a large area. Simultaneously, pre-stored channel fixed bias is introduced to compensate for ionospheric delay in the carrier phase. This allows for rapid estimation of a more accurate carrier frequency deviation based on the deviation between the ionospherically compensated carrier phase and the current carrier phase, enabling the carrier ring to quickly regain lock. This improves the dynamic tracking capability and anti-interference performance of the carrier ring without increasing hardware complexity, thereby enhancing the receiver's positioning availability. Attached Figure Description

[0016] Figure 1 This is a flowchart illustrating an adaptive tracking method based on deep collaboration between code ring and carrier ring in one embodiment. Figure 2 This is a schematic diagram illustrating the specific implementation steps of an adaptive tracking method based on deep collaboration between code ring and carrier ring in one embodiment; Figure 3 This is a schematic diagram of the tracking loop in one embodiment. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0018] In one embodiment, such as Figure 1 As shown, an adaptive tracking method based on deep collaboration between code ring and carrier ring is provided, including the following steps: Step 1: Monitor the environmental status of the receiver during signal tracking in real time. When it is determined that the current environment is weak signal / strong interference, switch the receiver's tracking loop route from the normal carrier loop-assisted code loop mode to the code loop-assisted carrier loop mode. At the same time, store the channel fixed deviation between the two loops caused by ionospheric delay during the switching.

[0019] Step 2: In code ring-assisted carrier ring mode, the code frequency and pseudorange information output in real time by the code ring are injected into the carrier ring as prior information. The carrier Doppler auxiliary frequency is calculated based on the code frequency. The carrier phase after ionospheric compensation is reconstructed based on the pseudorange information and the fixed channel deviation. The frequency correction is calculated based on the deviation between the carrier phase after ionospheric compensation and the current carrier phase. Finally, the carrier Doppler auxiliary frequency and the frequency correction are combined to help the carrier ring quickly recover lock and optimize the stable tracking of the carrier ring in weak signal / strong interference environment.

[0020] It should be understood that the aforementioned adaptive tracking method based on deep collaboration between the code ring and carrier ring innovatively employs a reverse mechanism of code ring-assisted carrier ring when the receiver encounters complex environments with weak signals and strong interference. This mechanism relies on the code frequency and pseudorange information output by the code ring to provide accurate prior information for the carrier ring, effectively avoiding the cumbersome process of large-range frequency search for the carrier ring. Simultaneously, it introduces pre-stored channel fixed bias to compensate for ionospheric delay in the carrier phase. This allows for rapid estimation of a more accurate carrier frequency deviation based on the deviation between the ionospherically compensated carrier phase and the current carrier phase, enabling the carrier ring to quickly regain lock and significantly improving the dynamic tracking performance of the carrier ring in low carrier-to-noise ratio and strong interference scenarios. Furthermore, the receiver can adaptively switch between carrier ring-assisted code ring and code ring-assisted carrier ring tracking schemes. Compared to a single carrier ring-assisted code ring mode, the receiver's overall anti-interference capability and environmental adaptability are significantly improved. At the same time, this method fully leverages the functional advantages of the code ring, significantly accelerating the reacquisition rate after lock-off, achieving a dual improvement in tracking accuracy and response speed.

[0021] Figure 2 This demonstrates the specific implementation steps of the method. Figure 2 In the illustrated embodiment, before signal tracking, the method further includes: Signal reception and preprocessing: Receive satellite radio frequency signals and perform preprocessing operations such as down-conversion, filtering, and sampling to obtain digital intermediate frequency signals.

[0022] Acquisition and Local Signal Generation and Correlation: Based on the coarse estimates obtained during the acquisition phase, a local carrier and a local pseudocode are generated. The local pseudocode generation parameters include the satellite PRN (pseudo-random noise code) number, code phase, and initial code frequency. The local carrier generation parameters include the carrier frequency and initial phase. The digital intermediate frequency signal is mixed and stripped with the local carrier and local pseudocode, and coherent integral values ​​for three branches—lead (E), immediate (P), and lag (L)—are generated through an I / Q correlator. The integration period can be adaptively adjusted according to the carrier-to-noise ratio; in weak signal scenarios, it can be appropriately extended to improve gain.

[0023] exist Figure 2 In the illustrated embodiment, calculating the carrier Doppler auxiliary frequency based on the code frequency includes: The code frequency output by the code ring in code ring assisted carrier ring mode is stable. Converted proportionally to carrier-Doppler auxiliary frequency , is represented as: ; in, For the signal carrier frequency, The pseudo-code rate (e.g., the carrier frequency of BeiDou B1I is 1561.098MHz, and the pseudo-code rate is 2.046MHz); carrier Doppler auxiliary frequency. Used as a feedforward injection into the frequency control terminal of the carrier NCO responsible for generating the local carrier in the carrier loop, it offsets most of the dynamic stress, ensuring that the carrier NCO frequency quickly approaches the true value.

[0024] exist Figure 2 In the illustrated embodiment, the carrier phase after ionospheric compensation is reconstructed based on pseudorange information and channel fixed deviation. The frequency correction is calculated based on the deviation between the ionospherically compensated carrier phase and the current carrier phase. Finally, the carrier loop is rapidly restored to lock by combining the carrier Doppler-assisted frequency and the frequency correction. This includes: Channel fixed deviation under ionospheric quiescence conditions (such as periods of geomagnetic quiescence) The ionospheric component in the data can be considered as a fixed bias, thus its characteristics can be used for ionospheric compensation, allowing for real-time acquisition of code loop pseudorange observations in code loop-assisted carrier loop mode. and combined with channel fixed deviation Reconstructed carrier phase prediction after ionospheric compensation , is represented as: ; in, The carrier wavelength; The deviation between the ionospherically compensated carrier phase prediction and the carrier NCO phase is converted into a frequency correction value. and frequency correction amount With carrier Doppler auxiliary frequency After superposition, they jointly drive the carrier NCO to assist the carrier loop in quickly restoring lock. The frequency superposition result is expressed as... .

[0025] exist Figure 2 In the illustrated embodiment, the channel fixed deviation is calculated and stored in real time in carrier loop-assisted code loop mode, and calculation stops when the tracking loop switches to code loop-assisted carrier loop mode; the channel fixed deviation The expression is: ; in, This is the weighting coefficient, with a value close to 1; For code ring pseudorange observations and The difference, after being low-pass filtered, is stored as a channel fixed bias. This is subsequently used to correct the ranging error of the code ring auxiliary carrier ring; These are carrier phase observations.

[0026] exist Figure 2 In the illustrated embodiment, the rule for determining whether the receiver's tracking loop routing carrier ring-assisted code ring mode switches to code ring-assisted carrier ring mode is as follows: By monitoring the phase error of the carrier loop output in real time during signal tracking, the carrier loop lock indication value is calculated. And combined with the current carrier-to-noise ratio of the signal Environmental status detection is performed. The carrier loop lock indication value is calculated as follows: The operating status of the carrier loop and code loop is monitored in real time during signal tracking. The absolute value of the phase error output by the carrier loop is taken and then filtered by a first-order low-pass filter to obtain the average phase jitter estimate. and will Mapped to carrier loop lock indicator value , is represented as: ; in, The preset carrier loop loss-of-lock threshold is typically set to 30°. When the jitter estimate exceeds 15°, it can be determined that there is a risk of carrier loop loss of lock.

[0027] Carrier loop lock indication value The carrier-to-noise ratio meets the condition of being higher than the preset first confidence threshold. If the conditions are met above the preset rise threshold and both conditions remain true for a duration exceeding the first preset duration, the current environment is determined to be a strong signal environment. In this case, the tracking loop maintains the normal carrier loop auxiliary code loop mode; at the carrier loop lock indicator value... The carrier-to-noise ratio meets the condition of being below the preset second confidence threshold. If the conditions are met below the preset descent threshold and both conditions remain true for a duration exceeding the second preset duration, the current environment is determined to be a weak signal / strong interference environment, and the tracking loop switches to the code loop-assisted carrier loop mode. Among these conditions, the preset first confidence threshold is greater than the preset second confidence threshold, the preset rise threshold is higher than the preset fall threshold, and the first preset duration is greater than the second preset duration. The two modes are adaptively switched based on the real-time environmental conditions to maintain continuous and robust signal tracking.

[0028] Specifically, the above-mentioned carrier loop locking indication value and carrier-to-noise ratio The adaptive switching between the two modes of the integrated decision can continue throughout the signal tracking process to achieve continuous and robust signal tracking until the tracking measurement results (pseudorange, carrier phase, Doppler) are output. For example, when... Below the preset descent threshold of 22dB-Hz If the level falls below the preset second confidence threshold of 0.5 and both conditions remain true for more than 1 second, the tracking loop immediately cuts off the auxiliary path from the carrier loop to the code loop and stops updating the channel fixation deviation caused by the ionosphere. Enable the code ring to the frequency-assisted path of the carrier ring. When 28dB-Hz higher than the preset rise threshold If the signal quality is higher than the preset first confidence threshold of 0.8 and both conditions are met for more than 2 seconds, it indicates that the signal quality has been restored. At this time, the tracking loop is restored to the normal carrier loop-assisted code loop mode.

[0029] In one embodiment, such as Figure 3 As shown, the tracking loop includes a signal forward path, a code loop module, and a carrier loop module.

[0030] The forward path includes an I / Q (in-phase / quadrature) mixer and an I / Q correlator. The I / Q mixer receives the input signal and multiplies it with the local carrier generated by the carrier loop module to perform carrier stripping and obtain the baseband signal. The I / Q correlator has three branches: lead (E), instantaneous (P), and lag (L). Each branch receives the baseband signal output from the I / Q mixer and performs correlation integration with the local pseudo-code generated by the code loop module, outputting the integration result. Figure 3 As shown, this includes the integral value of the lead code of the in-phase branch. I E Instantaneous code integral value of the same phase branch I P Integral value of the lag code of the in-phase branch I L Orthogonal branch lead code integral value Q EInstantaneous code integral value of the same phase branch Q P Integral value of orthogonal branch lag code Q L .

[0031] The code ring module adopts a second-order delay-locked loop (DLL) structure, including a code ring discriminator, a code ring filter, a C / A code NCO (numerically controlled oscillator), and a C / A code generator. The code ring discriminator is connected to the outputs of the lead and lag branches of the I / Q correlator. It employs an incoherent lead-lag amplitude reduction method to compare the amplitude differences between the lead and lag branches to extract the output code phase error. This phase error, after being filtered by the code ring filter, serves as the control input to the C / A code NCO, adjusting the frequency and phase of the local pseudo-code output by the C / A code generator. The local pseudo-code generated by the C / A code generator is then injected into the I / Q correlator. The code ring discriminator outputs the code phase error... Represented as: ; in, The square of the lead code integral value of the in-phase branch. The square of the integral value of the lead code of the orthogonal branch. It is the square of the integral value of the lag code of the in-phase branch. It is the square of the integral value of the lag code of the orthogonal branch. Figure 3 middle The amplitude of the leading branch, This represents the amplitude of the lagging branch. It should be understood that this is used in calculating the code phase error. At this time, the influence of carrier phase can be eliminated by calculating the amplitude (square root of power) of the I / Q branches. When the pseudocode phase deviation is less than 1 / 2 of the lead-hysteresis branch spacing, the output code phase error is... It is approximately linear with the phase error.

[0032] The carrier loop module employs a phase-locked loop (PLL) structure, comprising a carrier loop discriminator, a carrier loop filter, and a carrier NCO. The carrier loop discriminator is connected to the output of the instantaneous branch of the I / Q correlator to obtain the integral result of the instantaneous branch. A two-quadrant arctangent phase detector is used to extract the output phase error. After filtering by the carrier loop filter, the phase error drives the carrier NCO to adjust the local carrier frequency. The carrier NCO then generates a sine / cosine local carrier and injects it into the I / Q mixer. The phase error output by the carrier loop discriminator... Represented as: ; in, and These are the instantaneous code integral values ​​of the in-phase branch and the quadrature branch, respectively.

[0033] Combination Figure 3 As shown, when the tracking loop maintains the normal carrier loop-assisted code loop mode, the output of the carrier loop filter is also jointly input to the C / A code NCO with the output of the code loop filter to assist the C / A code generator in adjusting the phase and rate of the local pseudo-code.

[0034] Combination Figure 3 As shown, when the tracking loop switches to the code ring-assisted carrier ring mode, the output of the carrier ring filter is directly discarded, while the code frequency and pseudorange information output by the code ring filter are injected into the carrier ring as prior information. The carrier Doppler auxiliary frequency is calculated based on the code frequency, and the carrier phase after ionospheric compensation is reconstructed based on the pseudorange information and the stored channel fixed deviation. The frequency correction is calculated based on the deviation between the ionospherically compensated carrier phase and the current carrier phase. Finally, the carrier Doppler auxiliary frequency and the frequency correction are input to the carrier NCO to assist the carrier NCO in adjusting the phase and rate of the local carrier, thereby quickly restoring lock.

[0035] To further illustrate the performance of the method proposed in this application, the following tests were conducted. The test conditions are as follows: Navigation signal: Beidou B1I signal, center frequency 1561.098MHz, code rate 2.046MHz.

[0036] Interference type: Suppression interference, center frequency is the same as B1I, bandwidth ±2.046MHz.

[0037] Signal source: The signal source broadcasts the B1I signal in a static scene with a power of -133dBm.

[0038] Interference-to-signal ratio: the ratio of interference power to signal power.

[0039] Carrier-to-noise ratio: 35-41 dB·Hz in interference-free environment, and 15-25 dB·Hz in strong interference environment.

[0040] Comparison schemes: control group (traditional carrier-assisted code ring), experimental group (the code ring-assisted carrier ring hybrid scheme proposed in this application).

[0041] Evaluation indicators: positioning accuracy (horizontal less than 7m, elevation less than 9m), positioning success rate greater than 68%, each sampled 360 times.

[0042] The test results are shown in Tables 1 and 2.

[0043] Table 1 Test results of unidirectional interference sources

[0044] Table 2 Test results of three-directional interference sources

[0045] The test results shown in Tables 1 and 2 demonstrate that, under interference intensity near the antenna performance limit, the positioning success rate of the experimental group (this application) is significantly better than that of the control group. Even under adverse conditions with a 1dB improvement in the interference-to-signal ratio, this application can still maintain effective positioning, with an overall anti-interference capability improvement of approximately 1dB. The performance advantage of this application is particularly prominent in complex scenarios with multi-directional interference, verifying its stronger robustness and environmental adaptability in dealing with multi-source interference.

[0046] In one embodiment, an adaptive tracking system based on deep coordination of code ring and carrier ring is provided, comprising: The first unit is used to monitor the environmental status of the receiver in real time during the signal tracking process. When it is determined that the current environment is a weak signal / strong interference environment, the tracking loop route of the receiver is switched from the normal carrier loop assisted code loop mode to the code loop assisted carrier loop mode. At the same time, the channel fixed deviation caused by ionospheric delay between the two loops during the switching is stored. The second unit is used in code ring-assisted carrier ring mode to inject the code frequency and pseudorange information output by the code ring in real time as prior information into the carrier ring, calculate the carrier Doppler auxiliary frequency based on the code frequency, reconstruct the carrier phase after ionospheric compensation based on the pseudorange information and the fixed channel deviation, and calculate the frequency correction amount according to the deviation between the carrier phase after ionospheric compensation and the current carrier phase. Finally, the carrier Doppler auxiliary frequency and the frequency correction amount are combined to assist the carrier ring in quickly restoring lock and optimize the stable tracking of the carrier ring in weak signal / strong interference environment.

[0047] Specific limitations regarding the adaptive tracking system based on deep coordination of code ring and carrier ring can be found in the limitations of the adaptive tracking method based on deep coordination of code ring and carrier ring described above, and will not be repeated here. Each module in the aforementioned adaptive tracking system based on deep coordination of code ring and carrier ring can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in hardware or independently of the processor in a computer device, or stored in software in the memory of a computer device, so that the processor can call and execute the corresponding operations of each module.

[0048] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0049] The above embodiments are merely illustrative of several implementation methods of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of this application. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application.

Claims

1. An adaptive tracking method based on deep coordination of code ring and carrier ring, characterized in that, The method includes: The receiver's environmental status during signal tracking is monitored in real time. When it is determined that the current environment is weak signal / strong interference, the receiver's tracking loop route is switched from the normal carrier loop-assisted code loop mode to the code loop-assisted carrier loop mode. At the same time, the channel fixed deviation between the two loops caused by ionospheric delay during the switching is stored. In code-ring-assisted carrier-ring mode, the code frequency and pseudorange information output in real time by the code ring are injected into the carrier ring as prior information. The carrier Doppler auxiliary frequency is calculated based on the code frequency. The carrier phase after ionospheric compensation is reconstructed based on the pseudorange information and the fixed channel deviation. The frequency correction is calculated based on the deviation between the carrier phase after ionospheric compensation and the current carrier phase. Finally, the carrier Doppler auxiliary frequency and the frequency correction are combined to help the carrier ring quickly recover lock and optimize the stable tracking of the carrier ring in weak signal / strong interference environment.

2. The adaptive tracking method based on deep coordination of code ring and carrier ring according to claim 1, characterized in that, Calculating the carrier Doppler auxiliary frequency based on the code frequency includes: The code frequency output by the code ring in code ring assisted carrier ring mode is stable. Converted proportionally to carrier-Doppler auxiliary frequency , is represented as: ； in, For the signal carrier frequency, The pseudo-code rate; the carrier Doppler auxiliary frequency Used as a feedforward injection into the frequency control terminal of the carrier NCO responsible for generating the local carrier in the carrier loop, it offsets most of the dynamic stress, ensuring that the carrier NCO frequency quickly approaches the true value.

3. The adaptive tracking method based on deep coordination of code ring and carrier ring according to claim 2, characterized in that, Based on pseudorange information and channel fixed deviation, the ionospherically compensated carrier phase is reconstructed. The frequency correction is calculated based on the deviation between the ionospherically compensated carrier phase and the current carrier phase. Finally, the carrier Doppler-assisted frequency and the frequency correction are combined to assist in the rapid recovery and locking of the carrier loop, including: Real-time acquisition of code ring pseudorange observations in code ring-assisted carrier ring mode and combined with channel fixed deviation Reconstructed carrier phase prediction after ionospheric compensation , is represented as: ； in, The carrier wavelength; The deviation between the ionospherically compensated carrier phase prediction and the carrier NCO phase is converted into a frequency correction value. and the frequency correction amount With carrier Doppler auxiliary frequency After being superimposed, they jointly drive the carrier NCO to assist the carrier loop in quickly restoring lock.

4. The adaptive tracking method based on deep coordination of code ring and carrier ring according to claim 3, characterized in that, The channel fixed deviation is calculated and stored in real time in carrier loop-assisted code loop mode, and the calculation stops when the tracking loop switches to code loop-assisted carrier loop mode; channel fixed deviation The expression is: ； in, This is the weighting coefficient, with a value close to 1; For code ring pseudorange observations and The difference, These are carrier phase observations.

5. The adaptive tracking method based on deep coordination of code ring and carrier ring according to any one of claims 1 to 4, characterized in that, The rule for determining whether the receiver's tracking loop routing carrier ring-assisted code ring mode is switched to code ring-assisted carrier ring mode is as follows: By monitoring the phase error of the carrier loop output in real time during signal tracking, the carrier loop lock indication value is calculated and combined with the current carrier-to-noise ratio of the signal to detect the environmental status. When the carrier loop lock indicator value meets the condition of being higher than the preset first confidence threshold, the carrier-to-noise ratio meets the condition of being higher than the preset rise threshold, and the duration of both conditions being met exceeds the first preset duration, it is determined that the current environment is a strong signal environment, and at this time the tracking loop maintains the normal carrier loop auxiliary code loop mode. When the carrier loop lock indication value is lower than a preset second confidence threshold, the carrier-to-noise ratio is lower than a preset descent threshold, and both conditions are met for a duration exceeding a second preset duration, it is determined that the current environment is a weak signal / strong interference environment, and the tracking loop switches to code loop assisted carrier loop mode; wherein, the preset first confidence threshold is greater than the preset second confidence threshold, the preset rise threshold is greater than the preset fall threshold, and the first preset duration is greater than the second preset duration; The two modes adaptively switch based on real-time environmental conditions to maintain continuous and robust signal tracking.

6. The adaptive tracking method based on deep coordination of code ring and carrier ring according to claim 5, characterized in that, By monitoring the phase error of the carrier loop output in real time during signal tracking, the carrier loop lock indication value is calculated and obtained, including: The operating status of the carrier loop and code loop is monitored in real time during signal tracking. The absolute value of the phase error output by the carrier loop is taken and then filtered by a first-order low-pass filter to obtain the average phase jitter estimate. and will Mapped to carrier loop lock indicator value , is represented as: ； in, This is the preset carrier ring lockout threshold.

7. The adaptive tracking method based on deep coordination of code ring and carrier ring according to claim 1, characterized in that, The tracking loop includes a signal forward path, a code loop module, and a carrier loop module; The forward signal path includes an I / Q mixer and an I / Q correlator. The I / Q mixer receives the input signal and multiplies it with the local carrier generated by the carrier loop module to complete carrier stripping and obtain the baseband signal. The I / Q correlator is provided with three branches: lead, instant, and lag. Each branch receives the baseband signal output by the I / Q mixer and performs correlation integration with the local pseudocode generated by the code loop module to output the integration result. The code ring module adopts a second-order delay-locked loop structure, including a code ring discriminator, a code ring filter, a C / A code NCO, and a C / A code generator. The code ring discriminator is connected to the output terminals of the lead and lag branches of the I / Q correlator. It uses an incoherent lead-lag amplitude reduction method to compare the amplitude difference between the lead and lag branches to extract the output code phase error. The code phase error is filtered by the code ring filter and used as the control input of the C / A code NCO to adjust the frequency and phase of the local pseudo-code output by the C / A code generator. The local pseudo-code generated by the C / A code generator is then injected into the I / Q correlator. The carrier loop module adopts a phase-locked loop structure, including a carrier loop discriminator, a carrier loop filter, and a carrier NCO. The carrier loop discriminator is connected to the output of the instantaneous branch of the I / Q correlator to obtain the integral result of the instantaneous branch. It uses a two-quadrant arctangent phase detector to extract the output phase error. After the phase error is filtered by the carrier loop filter, it drives the carrier NCO to adjust the local carrier frequency. The carrier NCO generates a sine / cosine local carrier and injects it into the I / Q mixer.

8. The adaptive tracking method based on deep coordination of code ring and carrier ring according to claim 7, characterized in that, When the tracking loop maintains the normal carrier loop-assisted code loop mode, the output of the carrier loop filter is also jointly input to the C / A code NCO with the output of the code loop filter to assist the C / A code generator in adjusting the phase and rate of the local pseudo-code.

9. The adaptive tracking method based on deep coordination of code ring and carrier ring according to claim 8, characterized in that, When the tracking loop switches to the code-ring-assisted carrier-ring mode, the output of the carrier-ring filter is directly discarded, while the code frequency and pseudorange information output by the code-ring filter are injected into the carrier-ring as prior information. The carrier Doppler-assisted frequency is calculated based on the code frequency, and the carrier phase after ionospheric compensation is reconstructed based on the pseudorange information and the stored channel fixed deviation. The frequency correction is calculated based on the deviation between the ionospherically compensated carrier phase and the current carrier phase. Finally, the carrier Doppler-assisted frequency and the frequency correction are input to the carrier NCO to assist the carrier NCO in adjusting the phase and rate of the local carrier, thereby quickly restoring lock.

10. An adaptive tracking system based on deep coordination of code ring and carrier ring, characterized in that, The system includes: The first unit is used to monitor the environmental status of the receiver in real time during the signal tracking process. When it is determined that the current environment is a weak signal / strong interference environment, the tracking loop route of the receiver is switched from the normal carrier loop assisted code loop mode to the code loop assisted carrier loop mode. At the same time, the channel fixed deviation caused by ionospheric delay between the two loops during the switching is stored. The second unit is used in code ring-assisted carrier ring mode to inject the code frequency and pseudorange information output by the code ring in real time as prior information into the carrier ring, calculate the carrier Doppler auxiliary frequency based on the code frequency, reconstruct the carrier phase after ionospheric compensation based on the pseudorange information and the fixed channel deviation, and calculate the frequency correction amount according to the deviation between the carrier phase after ionospheric compensation and the current carrier phase. Finally, the carrier Doppler auxiliary frequency and the frequency correction amount are combined to assist the carrier ring in quickly restoring lock and optimize the stable tracking of the carrier ring in weak signal / strong interference environment.

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