A method and device for tracking an ultra-wideband navigation signal based on a linear frequency modulation spread code

Abstract

The application relates to a method and device for tracking an ultra-wideband navigation signal based on a linear frequency modulation spread code, and belongs to the technical field of satellite navigation. The method comprises the following steps: receiving an ultra-wideband navigation signal and multiplying the signal with a local in-phase carrier and a local quadrature carrier respectively to obtain in-phase components and quadrature components; obtaining a local linear frequency modulation spread code which is output after being bound by phase calculation, phase quantization, code generation and signal transmission time delay; obtaining a local pseudo-random spread code which is output after being bound by signal transmission time delay; combining the two types of spread codes to generate three types of spread codes, namely delayed, instant and advanced spread codes, and performing coherent integration on the in-phase components and the quadrature components which are divided into three paths; calculating the phase error and the time delay error of the current received signal and the local carrier according to the coherent integration result; and finally, repeatedly generating the carrier and the two types of spread codes based on error feedback to cyclically realize the tracking of the ultra-wideband navigation signal. The method can reduce the complexity of tracking the ultra-wideband navigation signal.

Description

Technical Field

[0001] This application relates to the field of satellite navigation technology, and in particular to an ultra-wideband navigation signal tracking method and apparatus based on linear frequency modulation spreading code. Background Technology

[0002] As the core of a nation's integrated positioning, navigation, and timing system, satellite navigation systems play a crucial role in providing a global, all-weather spatiotemporal reference. However, their signals have weak ground power and are highly susceptible to various types of interference, necessitating enhanced anti-interference performance in complex adversarial scenarios. With the increasing maturity of broadband spaceborne radio frequency amplifiers and antenna technology, broadcasting ultra-wideband navigation signals in the hundreds of megabits per second range has gradually become possible. These signals, with their lower power spectral density, stronger anti-interference capabilities, and higher measurement accuracy, have become the core development direction for the signal design of next-generation satellite navigation systems.

[0003] However, traditional navigation signals suffer from limitations such as insufficient Doppler immunity and low spectral efficiency in ultra-wideband scenarios. A pseudo-code phase modulation-linear frequency modulation composite modulation signal incorporating linear frequency modulation spreading codes can further improve Doppler immunity and ranging accuracy, but it presents certain challenges for user terminal reception. Regarding signal tracking, traditional navigation signals only need to estimate time-varying signal transmission delay and Doppler dynamics, while this composite modulation signal adds the linear frequency modulation spreading code as a tracking dimension, significantly increasing the complexity of the tracking algorithm. Summary of the Invention

[0004] Therefore, it is necessary to provide an ultra-wideband navigation signal tracking method and apparatus based on linear frequency modulation spreading code to address the technical problems of large tracking estimation dimension and high complexity in the ultra-wideband navigation signal tracking process of pseudo-code phase modulation-linear frequency modulation.

[0005] A method for tracking ultra-wideband navigation signals based on linear frequency modulation spreading codes, the method comprising:

[0006] The ultra-wideband navigation signal based on pseudocode phase modulation-linear frequency modulation is received after front-end filtering and down-conversion processing. It is then multiplied by the local in-phase carrier and local quadrature carrier output by the carrier generator to strip the carrier component, thus obtaining the in-phase component and quadrature component of the ultra-wideband navigation signal.

[0007] The local linear frequency modulation (LFM) spreading code is obtained after phase calculation, phase quantization, local LFM spreading code generation, and signal transmission delay binding by the LFM spreading code generator.

[0008] Obtain the local pseudo-random spreading code output by the pseudo-random spreading code generator after signal transmission delay binding;

[0009] By merging the local linear frequency modulation spreading code and the local pseudo-random spreading code, the three spreading codes required for code loop tracking—delayed, instantaneous, and leading—are generated, and the in-phase and quadrature components of the three paths are coherently integrated with the three spreading codes respectively.

[0010] Based on the instantaneous branch coherent integration results of the in-phase and quadrature components, the phase error between the current ultra-wideband navigation signal and the local carrier is calculated. Based on the delayed and leading branch coherent integration results of the in-phase and quadrature components, the time delay error between the current ultra-wideband navigation signal and the local carrier is calculated.

[0011] The phase error is fed back to the carrier generator, and the time delay error is fed back to the linear frequency modulation spreading code generator and the pseudo-random spreading code generator as reference information for the local signal in the next tracking loop. The above steps are repeated to achieve ultra-wideband navigation signal tracking.

[0012] In one embodiment, the local in-phase carrier and local quadrature carrier output by the carrier generator include:

[0013] At the initial moment, the carrier generator generates a local in-phase carrier and a local quadrature carrier based on the Doppler frequency information output by the acquisition loop; within the tracking loop, the carrier generator generates a local in-phase carrier and a local quadrature carrier based on the time delay error between the current UWB navigation signal and the local carrier.

[0014] Local in-phase carriers and local quadrature carriers are represented as follows:

[0015] ;

[0016] in, For local in-phase carriers, Local orthogonal carrier, The intermediate frequency (IF) for receiving signals. To estimate the Doppler frequency of the signal, To estimate the phase of the signal, The sampling interval is... It represents the beat of a clock.

[0017] In one embodiment, an ultra-wideband navigation signal based on pseudo-code phase modulation-linear frequency modulation, after front-end filtering and down-conversion processing, is received and multiplied by the local in-phase carrier and local quadrature carrier output from the carrier generator to strip the carrier component, respectively, to obtain the in-phase and quadrature components of the ultra-wideband navigation signal, including:

[0018] Receives ultra-wideband navigation signals based on pseudocode phase modulation-linear frequency modulation after front-end filtering and down-conversion processing. , is represented as:

[0019] ;

[0020] in, It is a pseudo-random spreading code. It is a linear frequency modulation spreading code. For signal transmission delay, The true Doppler frequency of the signal. This represents the true phase of the signal;

[0021] Ultra-wideband navigation signals Multiplying it by the local in-phase carrier output from the carrier generator yields the in-phase component. , is represented as:

[0022] ;

[0023] in, For frequency error, For phase error, Since these are high-frequency components, they can be filtered out during coherent integral calculations and are therefore ignored.

[0024] Ultra-wideband navigation signals Multiplying the quadrature carrier output by the carrier generator yields the quadrature component. , is represented as:

[0025] .

[0026] In one embodiment, obtaining the local linear frequency modulation (LFM) spreading code output by the LFM spreading code generator after phase calculation, phase quantization, local LFM spreading code generation, and signal transmission delay binding includes:

[0027] At the initial moment, the linear frequency modulation (LFM) spreading code generator generates a local LFM spreading code based on the signal transmission delay information output from the acquisition loop; during the tracking phase, the LFM spreading code generator generates a local LFM spreading code based on the delay error between the current ultra-wideband navigation signal and the local carrier; the local LFM spreading code is obtained as follows:

[0028] In a linear frequency modulation (LFM) spreading code generator, the phase of the output local LFM spreading code is first calculated, and expressed as:

[0029] ;

[0030] in, For the first Local linear frequency modulation spreading code phase value under each clock cycle, initial value The unit is week; For linear frequency modulation slope, For signal bandwidth, The signal sampling rate, This represents the modulo operation;

[0031] The local linear frequency modulation spreading code phase is then quantized to obtain the quantized phase angle. , represented as:

[0032] ;

[0033] in, To quantify the threshold, From a quantitative perspective, For the quantization space, it is determined by the number of quantization bits. Decision, that is If uniform quantization is used for phase quantization, then the first... Individual quantification threshold , No. From a quantitative perspective Taking the average of adjacent quantization thresholds, we have: ,in For quantization interval;

[0034] Then based on the quantized phase angle Generate quantized local linear frequency modulation spreading codes And estimate the transmission delay with the signal. Binding, ultimately outputting the local linear frequency modulation spreading code. , represented as:

[0035] ;

[0036] .

[0037] In one embodiment, obtaining the local pseudo-random spreading code output by the pseudo-random spreading code generator after transmission delay binding includes:

[0038] At the initial moment, the pseudo-random spreading code generator generates a local pseudo-random spreading code based on the signal transmission delay information output from the acquisition loop; during the tracking phase, the pseudo-random spreading code generator generates a local pseudo-random spreading code based on the delay error between the current ultra-wideband navigation signal and the local carrier; the local pseudo-random spreading code is represented as:

[0039] ;

[0040] in, It is a pseudo-random spreading code sequence.

[0041] In one embodiment, by merging the local linear frequency modulation spreading code and the local pseudo-random spreading code, the three spreading codes required for code ring tracking—delayed, immediate, and leading—are generated, respectively:

[0042] ;

[0043] in, , , These are, respectively, the delayed tributary spreading code, the immediate tributary spreading code, and the leading tributary spreading code. For code ring coherent interval, For clock beats, For local linear frequency modulation spreading code, It is a local pseudo-random spreading code.

[0044] In one embodiment, the in-phase and quadrature components, which are divided into three paths, are coherently integrated with the three spreading codes, including:

[0045] The in-phase components, divided into three paths, are respectively coupled with the spreading codes of the delayed branches. Instantaneous tributary spreading code Lead branch spreading code Coherent integration is performed to remove the spreading code components, yielding the coherent integration result of the delayed branch of the in-phase component. Instantaneous branch coherence integral results Coherent integral results of the leading branch , respectively represented as:

[0046] ;

[0047] in, , , These represent the time delay differences for delayed, immediate, and leading paths, respectively. For the autocorrelation function of the pseudo-random spreading code, For the autocorrelation function of the linear frequency modulation spreading code, For the coherent integration time, For frequency error, For phase error, Output amplitude;

[0048] The orthogonal components, divided into three paths, are respectively coupled with the spreading code of the delayed branch. Instantaneous tributary spreading code Lead branch spreading code Coherent integration is performed to remove the spreading code components, yielding the coherent integration result of the delayed branch of the orthogonal components. Instantaneous branch coherence integral results Coherent integral results of the leading branch , respectively represented as:

[0049] .

[0050] In one embodiment, the phase error between the current ultra-wideband navigation signal and the local carrier is calculated based on the instantaneous branch coherent integration results of the in-phase and quadrature components, and the time delay error between the current ultra-wideband navigation signal and the local carrier is calculated based on the delayed and leading branch coherent integration results of the in-phase and quadrature components, including:

[0051] Based on the instantaneous branch coherence integral results of the in-phase components Instantaneous branch coherence integral results of orthogonal components The phase error between the current ultra-wideband navigation signal and the local carrier is calculated using the two-quadrant arctangent function. , represented as:

[0052] ;

[0053] Based on the coherent integral results of the delayed branch of the in-phase component Coherent integral results with leading branch And the coherent integral results of the delayed branches of the orthogonal components. Coherent integral results with leading branch The incoherent lead-lag amplitude method is used to calculate the time delay error between the current ultra-wideband navigation signal and the local carrier. , represented as:

[0054] .

[0055] An ultra-wideband navigation signal tracking device based on linear frequency modulation spreading code, the device being used to implement the aforementioned ultra-wideband navigation signal tracking method based on linear frequency modulation spreading code, the device comprising:

[0056] A carrier generator is used to output local in-phase carriers and local quadrature carriers;

[0057] The first multiplication unit is used to receive the ultra-wideband navigation signal based on pseudocode phase modulation-linear frequency modulation after front-end filtering and down-conversion processing, and multiply it with the local in-phase carrier output by the carrier generator to strip the carrier component and obtain the in-phase component of the ultra-wideband navigation signal.

[0058] The second multiplication unit is used to receive the ultra-wideband navigation signal based on pseudocode phase modulation-linear frequency modulation after front-end filtering and down-conversion processing, and multiply it with the local orthogonal carrier output by the carrier generator to strip the carrier component and obtain the orthogonal component of the ultra-wideband navigation signal.

[0059] A linear frequency modulation (LFM) spreading code generator is used to output local LFM spreading codes after phase calculation, phase quantization, local LFM spreading code generation, and signal transmission delay binding.

[0060] A pseudo-random spreading code generator is used to output a local pseudo-random spreading code after signal transmission delay binding.

[0061] The merging unit is used to merge the local linear frequency modulation spreading code and the local pseudo-random spreading code to generate the three spreading codes required for code loop tracking: delayed, instantaneous, and leading.

[0062] The in-phase component coherent integration unit includes three in-phase component coherent integration branches. Each in-phase component coherent integration branch consists of a multiplication unit and an integrator. It is used to coherently integrate the in-phase components divided into three paths with the delayed branch spreading code, the instantaneous branch spreading code, and the leading branch spreading code, respectively, to obtain the delayed branch coherent integration result, the instantaneous branch coherent integration result, and the leading branch coherent integration result of the in-phase component.

[0063] The quadrature component coherent integration unit includes three quadrature component coherent integration branches. Each quadrature component coherent integration branch consists of a multiplication unit and an integrator. It is used to coherently integrate the three quadrature components with the delayed branch spreading code, the instantaneous branch spreading code, and the leading branch spreading code, respectively, to obtain the delayed branch coherent integration result, the instantaneous branch coherent integration result, and the leading branch coherent integration result of the quadrature components.

[0064] The frequency discriminator is used to calculate the phase error between the current ultra-wideband navigation signal and the local carrier based on the instantaneous branch coherent integration results of the in-phase and quadrature components, and feeds the phase error back to the carrier generator as reference information for the local signal in the next tracking loop, so as to realize ultra-wideband navigation signal tracking in a loop.

[0065] The delay discriminator is used to calculate the delay error between the current ultra-wideband navigation signal and the local carrier based on the coherent integration results of the delayed and leading branches of the in-phase and quadrature components. The delay error is then fed back to the linear frequency modulation spreading code generator and the pseudo-random spreading code generator as reference information for the local signal in the next tracking loop, so as to realize the ultra-wideband navigation signal tracking in a loop.

[0066] In one embodiment, the linear frequency modulation spreading code generator includes a phase calculation module, a phase quantization module, and a local linear frequency modulation spreading code generation module;

[0067] The phase calculation module is used to calculate the phase of the output local linear frequency modulation spreading code, which is represented as:

[0068] ;

[0069] in, For the first Local linear frequency modulation spreading code phase value under each clock cycle, initial value The unit is week; For linear frequency modulation slope, For signal bandwidth, The signal sampling rate, This represents the modulo operation;

[0070] The phase quantization module is used to quantize the phase of the local linear frequency modulation spreading code to obtain the quantized phase angle. , represented as:

[0071] ;

[0072] in, To quantify the threshold, From a quantitative perspective, For the quantization space, it is determined by the number of quantization bits. Decision, that is If uniform quantization is used for phase quantization, then the first... Individual quantification threshold , No. From a quantitative perspective Taking the average of adjacent quantization thresholds, we have: ,in For quantization interval;

[0073] The local linear frequency modulation spreading code generation module is used to generate the code based on the quantized phase angle. Generate quantized local linear frequency modulation spreading codes And estimate the transmission delay with the signal. Binding, ultimately outputting the local linear frequency modulation spreading code. , represented as:

[0074] ;

[0075] .

[0076] The aforementioned ultra-wideband navigation signal tracking method and device based on linear frequency modulation (LFM) spreading codes has the following advantages: 1. By binding the local LFM spreading code with the signal transmission delay, the tracking dimension of the newly added LFM spreading code in the ultra-wideband navigation signal is unified with the signal transmission delay, eliminating the need for separate estimation of multiple dimensions and effectively solving the problem of large tracking estimation dimensions and high complexity for this type of composite modulation signal. 2. By designing a tracking device structure adapted to ultra-wideband navigation signals based on pseudo-code phase modulation-linear frequency modulation, while maintaining the same tracking estimation complexity as traditional navigation signals, mature algorithm logic is used, reducing the development and upgrade costs of ultra-wideband navigation signal terminals and providing key technical support for the application of ultra-wideband navigation signals. 3. Through phase quantization design of the LFM spreading code generator, while achieving equivalent spreading capability, the computational complexity and hardware implementation complexity of local LFM spreading code generation are greatly simplified, making it more suitable for engineering needs in resource-constrained scenarios such as spaceborne systems. Attached Figure Description

[0077] Figure 1 This is a flowchart illustrating an ultra-wideband navigation signal tracking method based on linear frequency modulation spreading code in one embodiment.

[0078] Figure 2 This is a waveform diagram of an ultra-wideband navigation signal in one embodiment;

[0079] Figure 3 This is a schematic diagram of the structure of an ultra-wideband navigation signal tracking device based on linear frequency modulation spreading code in one embodiment;

[0080] Figure 4 This is a schematic diagram of the internal structure of a linear frequency modulation spreading code generator in one embodiment. Detailed Implementation

[0081] 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.

[0082] In one embodiment, such as Figure 1 As shown, an ultra-wideband navigation signal tracking method based on linear frequency modulation spreading code is provided, including the following steps:

[0083] Step 1: Receive the ultra-wideband navigation signal based on pseudocode phase modulation-linear frequency modulation after front-end filtering and down-conversion processing, and multiply it by the local in-phase carrier and local quadrature carrier output by the carrier generator respectively to strip the carrier component, so as to obtain the in-phase component and quadrature component of the ultra-wideband navigation signal.

[0084] Step 2: Obtain the local linear frequency modulation (LFM) spreading code output by the LFM spreading code generator after phase calculation, phase quantization, local LFM spreading code generation, and signal transmission delay binding.

[0085] Step 3: Obtain the local pseudo-random spreading code output by the pseudo-random spreading code generator after signal transmission delay binding.

[0086] Step 4: By merging the local linear frequency modulation spreading code and the local pseudo-random spreading code, the three spreading codes required for code loop tracking—delayed, instantaneous, and leading—are generated. The in-phase and quadrature components of the three paths are then coherently integrated with the three spreading codes.

[0087] Step 5: Calculate the phase error between the current UWB navigation signal and the local carrier based on the instantaneous branch coherent integration results of the in-phase and quadrature components. Calculate the time delay error between the current UWB navigation signal and the local carrier based on the delayed and leading branch coherent integration results of the in-phase and quadrature components.

[0088] Step 6: Feed back the phase error to the carrier generator, and feed back the time delay error to the linear frequency modulation spreading code generator and the pseudo-random spreading code generator, as reference information for the local signal in the next tracking loop, and repeat the above steps to achieve ultra-wideband navigation signal tracking.

[0089] The aforementioned ultra-wideband navigation signal tracking method based on linear frequency modulation (LFM) spreading codes generates the spreading code required for code ring tracking by fusing local LFM spreading codes and pseudo-random spreading codes. The added LFM code tracking dimension is unified with the signal transmission delay. While maintaining the same tracking complexity as traditional navigation signals, a delay-locked loop (LLL) is used for matched filtering tracking, providing key technical support for the application of ultra-wideband navigation signals. Furthermore, by using phase quantization design in the LFM spreading code generator, equivalent spreading capability can be achieved while significantly simplifying the computational and hardware implementation complexity of local LFM spreading code generation, making it more suitable for engineering needs in resource-constrained scenarios such as spaceborne systems.

[0090] In one embodiment, the local in-phase carrier and local quadrature carrier output by the carrier generator include:

[0091] At the initial moment, the carrier generator generates a local in-phase carrier and a local quadrature carrier based on the Doppler frequency information output by the acquisition loop; within the tracking loop, the carrier generator generates a local in-phase carrier and a local quadrature carrier based on the time delay error between the current UWB navigation signal and the local carrier.

[0092] Local in-phase carriers and local quadrature carriers are represented as follows:

[0093] ;

[0094] in, For local in-phase carriers, Local orthogonal carrier, The intermediate frequency (IF) for receiving signals. To estimate the Doppler frequency of the signal, To estimate the phase of the signal, The sampling interval is... It represents the beat of a clock.

[0095] In one embodiment, an ultra-wideband navigation signal based on pseudo-code phase modulation-linear frequency modulation, after front-end filtering and down-conversion processing, is received and multiplied by the local in-phase carrier and local quadrature carrier output from the carrier generator to strip the carrier component, respectively, to obtain the in-phase and quadrature components of the ultra-wideband navigation signal, including:

[0096] Receives ultra-wideband navigation signals based on pseudocode phase modulation-linear frequency modulation after front-end filtering and down-conversion processing. Ultra-wideband navigation signal waveforms are as follows Figure 2 As shown, Specifically, it is expressed as follows:

[0097] ;

[0098] in, It is a pseudo-random spreading code. It is a linear frequency modulation spreading code. For signal transmission delay, The true Doppler frequency of the signal. This represents the true phase of the signal;

[0099] Ultra-wideband navigation signals Multiplying it by the local in-phase carrier output from the carrier generator yields the in-phase component. , is represented as:

[0100] ;

[0101] in, For frequency error, For phase error, Since these are high-frequency components, they can be filtered out during coherent integral calculations and are therefore ignored.

[0102] Ultra-wideband navigation signals Multiplying the quadrature carrier output by the carrier generator yields the quadrature component. , is represented as:

[0103] .

[0104] In one embodiment, obtaining the local linear frequency modulation (LFM) spreading code output by the LFM spreading code generator after phase calculation, phase quantization, local LFM spreading code generation, and signal transmission delay binding includes:

[0105] At the initial moment, the linear frequency modulation (LFM) spreading code generator generates a local LFM spreading code based on the signal transmission delay information output from the acquisition loop; during the tracking phase, the LFM spreading code generator generates a local LFM spreading code based on the delay error between the current ultra-wideband navigation signal and the local carrier; the local LFM spreading code is obtained as follows:

[0106] In a linear frequency modulation (LFM) spreading code generator, the phase of the output local LFM spreading code is first calculated, and expressed as:

[0107] ;

[0108] in, For the first Local linear frequency modulation spreading code phase value under each clock cycle, initial value The unit is week; For linear frequency modulation slope, For signal bandwidth, The signal sampling rate, This represents the modulo operation;

[0109] The local linear frequency modulation spreading code phase is then quantized to obtain the quantized phase angle. , is represented as:

[0110] ;

[0111] in, To quantify the threshold, From a quantitative perspective, For quantization space, it is determined by the number of quantization bits. Decision, that is If uniform quantization is used for phase quantization, then the first... Individual quantification threshold , No. From a quantitative perspective Taking the average of adjacent quantization thresholds, we have: ,in For quantization interval; it should be understood that this phase quantization method, by performing segmented quantization processing on the linear frequency modulated waveform, significantly reduces the computational complexity and hardware implementation complexity of local linear frequency modulated spreading code generation while preserving the signal's equivalent spreading capability and constant envelope characteristics, making it more suitable for the engineering needs of resource-constrained scenarios such as spaceborne.

[0112] Then based on the quantized phase angle Generate quantized local linear frequency modulation spreading codes And estimate the transmission delay with the signal. Binding, ultimately outputting the local linear frequency modulation spreading code. , is represented as:

[0113] ;

[0114] .

[0115] In one embodiment, obtaining the local pseudo-random spreading code output by the pseudo-random spreading code generator after transmission delay binding includes:

[0116] At the initial moment, the pseudo-random spreading code generator generates a local pseudo-random spreading code based on the signal transmission delay information output from the acquisition loop; during the tracking phase, the pseudo-random spreading code generator generates a local pseudo-random spreading code based on the delay error between the current ultra-wideband navigation signal and the local carrier; the local pseudo-random spreading code is represented as:

[0117] ;

[0118] in, It is a pseudo-random spreading code sequence.

[0119] In one embodiment, by merging the local linear frequency modulation spreading code and the local pseudo-random spreading code, the three spreading codes required for code ring tracking—delayed, immediate, and leading—are generated, respectively:

[0120] ;

[0121] in, , , These are, respectively, the delayed tributary spreading code, the immediate tributary spreading code, and the leading tributary spreading code. For code ring coherent interval, For the clock beat, For local linear frequency modulation spreading code, It is a local pseudo-random spreading code.

[0122] In one embodiment, the in-phase and quadrature components, which are divided into three paths, are coherently integrated with the three spreading codes, including:

[0123] The in-phase components, divided into three paths, are respectively coupled with the spreading codes of the delayed branches. Instantaneous tributary spreading code Lead branch spreading code Coherent integration is performed to remove the spreading code components, yielding the coherent integration result of the delayed branch of the in-phase component. Instantaneous branch coherence integral results Coherent integral results of the leading branch , respectively represented as:

[0124] ;

[0125] in, , , These represent the time delay differences for delayed, immediate, and leading paths, respectively. For the autocorrelation function of the pseudo-random spreading code, For the autocorrelation function of the linear frequency modulation spreading code, For the coherent integration time, For frequency error, For phase error, Output amplitude;

[0126] The orthogonal components, divided into three paths, are respectively coupled with the spreading code of the delayed branch. Instantaneous tributary spreading code Lead branch spreading code Coherent integration is performed to remove the spreading code components, yielding the coherent integration result of the delayed branch of the orthogonal components. Instantaneous branch coherence integral results Coherent integral results of the leading branch , respectively represented as:

[0127] .

[0128] In one embodiment, the phase error between the current ultra-wideband navigation signal and the local carrier is calculated based on the instantaneous branch coherent integration results of the in-phase and quadrature components, and the time delay error between the current ultra-wideband navigation signal and the local carrier is calculated based on the delayed and leading branch coherent integration results of the in-phase and quadrature components, including:

[0129] Based on the instantaneous branch coherence integral results of the in-phase components Instantaneous branch coherence integral results of orthogonal components The phase error between the current ultra-wideband navigation signal and the local carrier is calculated using the two-quadrant arctangent function. , is represented as:

[0130] ;

[0131] Based on the coherent integral results of the delayed branch of the in-phase component Coherent integral results with leading branch And the coherent integral results of the delayed branches of the orthogonal components. Coherent integral results with leading branch The incoherent lead-lag amplitude method is used to calculate the time delay error between the current ultra-wideband navigation signal and the local carrier. , is represented as:

[0132] .

[0133] In one embodiment, such as Figure 3 As shown, an ultra-wideband navigation signal tracking device based on linear frequency modulation (LFM) spreading code is provided. This device is used to implement the aforementioned ultra-wideband navigation signal tracking method based on LFM spreading code. The device includes:

[0134] A carrier generator is used to output local in-phase carriers and local quadrature carriers;

[0135] The first multiplication unit is used to receive the ultra-wideband navigation signal based on pseudocode phase modulation-linear frequency modulation after front-end filtering and down-conversion processing, and multiply it with the local in-phase carrier output by the carrier generator to strip the carrier component and obtain the in-phase component of the ultra-wideband navigation signal.

[0136] The second multiplication unit is used to receive the ultra-wideband navigation signal based on pseudocode phase modulation-linear frequency modulation after front-end filtering and down-conversion processing, and multiply it with the local orthogonal carrier output by the carrier generator to strip the carrier component and obtain the orthogonal component of the ultra-wideband navigation signal.

[0137] A linear frequency modulation (LFM) spreading code generator is used to output local LFM spreading codes after phase calculation, phase quantization, local LFM spreading code generation, and signal transmission delay binding.

[0138] A pseudo-random spreading code generator is used to output a local pseudo-random spreading code after signal transmission delay binding.

[0139] The merging unit is used to merge the local linear frequency modulation spreading code and the local pseudo-random spreading code to generate the three spreading codes required for code loop tracking: delayed, instantaneous, and leading.

[0140] The in-phase component coherent integration unit includes three in-phase component coherent integration branches. Each in-phase component coherent integration branch consists of a multiplication unit and an integrator. It is used to coherently integrate the in-phase components divided into three paths with the delayed branch spreading code, the instantaneous branch spreading code, and the leading branch spreading code, respectively, to obtain the delayed branch coherent integration result, the instantaneous branch coherent integration result, and the leading branch coherent integration result of the in-phase component.

[0141] The quadrature component coherent integration unit includes three quadrature component coherent integration branches. Each quadrature component coherent integration branch consists of a multiplication unit and an integrator. It is used to coherently integrate the three quadrature components with the delayed branch spreading code, the instantaneous branch spreading code, and the leading branch spreading code, respectively, to obtain the delayed branch coherent integration result, the instantaneous branch coherent integration result, and the leading branch coherent integration result of the quadrature components.

[0142] The frequency discriminator is used to calculate the phase error between the current ultra-wideband navigation signal and the local carrier based on the instantaneous branch coherent integration results of the in-phase and quadrature components, and feeds the phase error back to the carrier generator as reference information for the local signal in the next tracking loop, so as to realize ultra-wideband navigation signal tracking in a loop.

[0143] The delay discriminator is used to calculate the delay error between the current ultra-wideband navigation signal and the local carrier based on the coherent integration results of the delayed and leading branches of the in-phase and quadrature components. The delay error is then fed back to the linear frequency modulation spreading code generator and the pseudo-random spreading code generator as reference information for the local signal in the next tracking loop, so as to realize the ultra-wideband navigation signal tracking in a loop.

[0144] In one embodiment, such as Figure 4 As shown, the linear frequency modulation spreading code generator includes a phase calculation module, a phase quantization module, and a local linear frequency modulation spreading code generation module.

[0145] The phase calculation module is used to calculate the phase of the output local linear frequency modulation spreading code, which is represented as:

[0146] ;

[0147] in, For the first Local linear frequency modulation spreading code phase value under each clock cycle, initial value The unit is week; For linear frequency modulation slope, For signal bandwidth, The signal sampling rate, This represents the modulo operation;

[0148] The phase quantization module is used to quantize the phase of the local linear frequency modulation spreading code to obtain the quantized phase angle. , is represented as:

[0149] ;

[0150] in, To quantify the threshold, From a quantitative perspective, For quantization space, it is determined by the number of quantization bits. Decision, that is If uniform quantization is used for phase quantization, then the first... Individual quantification threshold , No. From a quantitative perspective Taking the average of adjacent quantization thresholds, we have: ,in For quantization interval;

[0151] The local linear frequency modulation spreading code generation module is used to generate the code based on the quantized phase angle. Generate quantized local linear frequency modulation spreading codes And estimate the transmission delay with the signal. Binding, ultimately outputting the local linear frequency modulation spreading code. , is represented as:

[0152] ;

[0153] .

[0154] Specific limitations regarding the ultra-wideband navigation signal tracking device based on linear frequency modulation (LFM) spreading codes can be found in the limitations of the ultra-wideband navigation signal tracking method based on LFM spreading codes described above, and will not be repeated here. Each module in the aforementioned ultra-wideband navigation signal tracking device based on LFM spreading codes 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.

[0155] 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.

[0156] 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. A method for tracking ultra-wideband navigation signals based on linear frequency modulation spreading codes, characterized in that, include: The ultra-wideband navigation signal based on pseudocode phase modulation-linear frequency modulation is received after front-end filtering and down-conversion processing. It is then multiplied by the local in-phase carrier and local quadrature carrier output by the carrier generator to strip the carrier component, thus obtaining the in-phase component and quadrature component of the ultra-wideband navigation signal. The local linear frequency modulation (LFM) spreading code is obtained after phase calculation, phase quantization, local LFM spreading code generation, and signal transmission delay binding by the LFM spreading code generator. Obtain the local pseudo-random spreading code output by the pseudo-random spreading code generator after signal transmission delay binding; By merging the local linear frequency modulation spreading code and the local pseudo-random spreading code, the three spreading codes required for code loop tracking—delayed, instantaneous, and leading—are generated, and the in-phase and quadrature components of the three paths are coherently integrated with the three spreading codes respectively. Based on the instantaneous branch coherent integration results of the in-phase and quadrature components, the phase error between the current ultra-wideband navigation signal and the local carrier is calculated. Based on the delayed and leading branch coherent integration results of the in-phase and quadrature components, the time delay error between the current ultra-wideband navigation signal and the local carrier is calculated. The phase error is fed back to the carrier generator, and the time delay error is fed back to the linear frequency modulation spreading code generator and the pseudo-random spreading code generator, as reference information for the local signal in the next tracking loop, and so on, to achieve ultra-wideband navigation signal tracking; The local in-phase carrier and local quadrature carrier output by the carrier generator include: At the initial moment, the carrier generator generates a local in-phase carrier and a local quadrature carrier based on the Doppler frequency information output by the acquisition loop; within the tracking loop, the carrier generator generates a local in-phase carrier and a local quadrature carrier based on the time delay error between the current ultra-wideband navigation signal and the local carrier. The local in-phase carrier and the local quadrature carrier are respectively represented as follows: ； in, For local in-phase carriers, Local orthogonal carrier, The intermediate frequency (IF) for receiving signals. To estimate the Doppler frequency of the signal, To estimate the phase of the signal, The sampling interval is... It represents the beat of a clock.

2. The ultra-wideband navigation signal tracking method based on linear frequency modulation spreading code according to claim 1, characterized in that, The system receives an ultra-wideband navigation signal based on pseudo-code phase modulation-linear frequency modulation (PMFM) after front-end filtering and down-conversion processing. This signal is then multiplied by the local in-phase carrier and local quadrature carrier output from the carrier generator to strip the carrier component, yielding the in-phase and quadrature components of the ultra-wideband navigation signal, including: Receives ultra-wideband navigation signals based on pseudocode phase modulation-linear frequency modulation after front-end filtering and down-conversion processing. , is represented as: ； in, It is a pseudo-random spreading code. It is a linear frequency modulation spreading code. For signal transmission delay, The true Doppler frequency of the signal. This represents the true phase of the signal; Ultra-wideband navigation signals Multiplying it by the local in-phase carrier output from the carrier generator yields the in-phase component. , represented as: ； in, For frequency error, For phase error, Since these are high-frequency components, they can be filtered out during coherent integral calculations and are therefore ignored. Ultra-wideband navigation signals Multiplying the quadrature carrier output by the carrier generator yields the quadrature component. , represented as: 。 3. The ultra-wideband navigation signal tracking method based on linear frequency modulation spreading code according to claim 2, characterized in that, The local linear frequency modulation (LFM) spreading code output by the LFM spreading code generator after phase calculation, phase quantization, local LFM spreading code generation, and signal transmission delay binding includes: At the initial moment, the linear frequency modulation (LFM) spreading code generator generates a local LFM spreading code based on the signal transmission delay information output by the acquisition loop; during the tracking phase, the LFM spreading code generator generates a local LFM spreading code based on the delay error between the current ultra-wideband navigation signal and the local carrier; the local LFM spreading code is obtained as follows: In the linear frequency modulation spreading code generator, the phase of the output local linear frequency modulation spreading code is first calculated and expressed as: ； in, For the first Local linear frequency modulation spreading code phase under each clock cycle, initial value The unit is week; For linear frequency modulation slope, For signal bandwidth, The signal sampling rate, This represents the modulo operation; The local linear frequency modulation spreading code phase is then quantized to obtain the quantized phase angle. , is represented as: ； in, To quantify the threshold, From a quantitative perspective, For quantization space, it is determined by the number of quantization bits. Decision, that is If uniform quantization is used for phase quantization, then the first... Individual quantification threshold , No. From a quantitative perspective Taking the average of adjacent quantization thresholds, we have: ,in For quantization interval; Then based on the quantized phase angle Generate quantized local linear frequency modulation spreading codes And estimate the transmission delay with the signal. Binding, ultimately outputting the local linear frequency modulation spreading code. , is represented as: ； 。 4. The ultra-wideband navigation signal tracking method based on linear frequency modulation spreading code according to claim 3, characterized in that, Obtain the local pseudo-random spreading code output by the pseudo-random spreading code generator after transmission delay binding, including: At the initial moment, the pseudo-random spreading code generator generates a local pseudo-random spreading code based on the signal transmission delay information output by the acquisition loop; during the tracking phase, the pseudo-random spreading code generator generates a local pseudo-random spreading code based on the delay error between the current ultra-wideband navigation signal and the local carrier; the local pseudo-random spreading code is represented as: ； in, It is a pseudo-random spreading code sequence.

5. The ultra-wideband navigation signal tracking method based on linear frequency modulation spreading code according to claim 4, characterized in that, By merging the local linear frequency modulation spreading code and the local pseudo-random spreading code, the three spreading codes required for code ring tracking—delayed, immediate, and leading—are generated, respectively, as follows: ； in, , , These are, respectively, the delayed tributary spreading code, the immediate tributary spreading code, and the leading tributary spreading code. For code ring coherent interval, For the clock beat, For local linear frequency modulation spreading code, It is a local pseudo-random spreading code.

6. The ultra-wideband navigation signal tracking method based on linear frequency modulation spreading code according to claim 5, characterized in that, The in-phase and quadrature components, which are divided into three paths, are coherently integrated with the three spreading codes, including: The in-phase components, divided into three paths, are respectively coupled with the spreading codes of the delayed branches. Instantaneous tributary spreading code Lead branch spreading code Coherent integration is performed to remove the spreading code components, yielding the coherent integration result of the delayed branch of the in-phase component. Instantaneous branch coherence integral results Coherent integral results of the leading branch , respectively represented as: ； in, , , These represent the time delay differences for delayed, immediate, and leading paths, respectively. For the autocorrelation function of the pseudo-random spreading code, For the autocorrelation function of the linear frequency modulation spreading code, For the coherent integration time, For frequency error, For phase error, Output amplitude; The orthogonal components, divided into three paths, are respectively coupled with the spreading code of the delayed branch. Instantaneous tributary spreading code Lead branch spreading code Coherent integration is performed to remove the spreading code components, yielding the coherent integration result of the delayed branch of the orthogonal components. Instantaneous branch coherence integral results Coherent integral results of the leading branch , respectively represented as: 。 7. The ultra-wideband navigation signal tracking method based on linear frequency modulation spreading code according to claim 6, characterized in that, Based on the instantaneous branch coherent integration results of the in-phase and quadrature components, the phase error between the current UWB navigation signal and the local carrier is calculated. Based on the delayed and leading branch coherent integration results of the in-phase and quadrature components, the time delay error between the current UWB navigation signal and the local carrier is calculated, including: Based on the instantaneous branch coherence integral results of the in-phase components Instantaneous branch coherence integral results of orthogonal components The phase error between the current ultra-wideband navigation signal and the local carrier is calculated using the two-quadrant arctangent function. , represented as: ； Based on the coherent integral results of the delayed branch of the in-phase component Coherent integral results with leading branch And the coherent integral results of the delayed branches of the orthogonal components. Coherent integral results with leading branch The incoherent lead-lag amplitude method is used to calculate the time delay error between the current ultra-wideband navigation signal and the local carrier. , represented as: 。 8. A wideband navigation signal tracking device based on linear frequency modulation spreading code, characterized in that, A method for implementing an ultra-wideband navigation signal tracking method based on linear frequency modulation spreading code as described in any one of claims 1-7 includes: A carrier generator is used to output local in-phase carriers and local quadrature carriers; The first multiplication unit is used to receive the ultra-wideband navigation signal based on pseudocode phase modulation-linear frequency modulation after front-end filtering and down-conversion processing, and multiply it with the local in-phase carrier output by the carrier generator to strip the carrier component and obtain the in-phase component of the ultra-wideband navigation signal. The second multiplication unit is used to receive the ultra-wideband navigation signal based on pseudocode phase modulation-linear frequency modulation after front-end filtering and down-conversion processing, and multiply it with the local orthogonal carrier output by the carrier generator to strip the carrier component and obtain the orthogonal component of the ultra-wideband navigation signal. A linear frequency modulation (LFM) spreading code generator is used to output local LFM spreading codes after phase calculation, phase quantization, local LFM spreading code generation, and signal transmission delay binding. A pseudo-random spreading code generator is used to output a local pseudo-random spreading code after signal transmission delay binding. The merging unit is used to merge the local linear frequency modulation spreading code and the local pseudo-random spreading code to generate the three spreading codes required for code loop tracking: delayed, instantaneous, and leading. The in-phase component coherent integration unit includes three in-phase component coherent integration branches. Each in-phase component coherent integration branch consists of a multiplication unit and an integrator. It is used to coherently integrate the in-phase components divided into three paths with the delayed branch spreading code, the instantaneous branch spreading code, and the leading branch spreading code, respectively, to obtain the delayed branch coherent integration result, the instantaneous branch coherent integration result, and the leading branch coherent integration result of the in-phase component. The quadrature component coherent integration unit includes three quadrature component coherent integration branches. Each quadrature component coherent integration branch consists of a multiplication unit and an integrator. It is used to coherently integrate the three quadrature components with the delayed branch spreading code, the instantaneous branch spreading code, and the leading branch spreading code, respectively, to obtain the delayed branch coherent integration result, the instantaneous branch coherent integration result, and the leading branch coherent integration result of the quadrature components. The frequency discriminator is used to calculate the phase error between the current ultra-wideband navigation signal and the local carrier based on the instantaneous branch coherent integration results of the in-phase and quadrature components, and feeds the phase error back to the carrier generator as reference information for the local signal in the next tracking loop, so as to realize ultra-wideband navigation signal tracking in a loop. The delay discriminator is used to calculate the delay error between the current ultra-wideband navigation signal and the local carrier based on the coherent integration results of the delayed and leading branches of the in-phase and quadrature components. The delay error is then fed back to the linear frequency modulation spreading code generator and the pseudo-random spreading code generator as reference information for the local signal in the next tracking loop, so as to realize the ultra-wideband navigation signal tracking in a loop.

9. The ultra-wideband navigation signal tracking device based on linear frequency modulation spreading code according to claim 8, characterized in that, The linear frequency modulation spreading code generator includes a phase calculation module, a phase quantization module, and a local linear frequency modulation spreading code generation module; The phase calculation module is used to calculate and output the phase of the local linear frequency modulation spreading code, which is represented as follows: ； in, For the first Local linear frequency modulation spreading code phase under each clock cycle, initial value The unit is week; For linear frequency modulation slope, For signal bandwidth, The signal sampling rate, This represents the modulo operation; The phase quantization module is used to quantize the phase of the local linear frequency modulation spreading code to obtain the quantized phase angle. , represented as: ； in, To quantify the threshold, From a quantitative perspective, For the quantization space, it is determined by the number of quantization bits. Decision, that is If uniform quantization is used for phase quantization, then the first... Individual quantification threshold , No. From a quantitative perspective Taking the average of adjacent quantization thresholds, we have: ,in For quantization interval; The local linear frequency modulation spreading code generation module is used to generate the quantized phase angle. Generate quantized local linear frequency modulation spreading codes And estimate the transmission delay with the signal. Binding, ultimately outputting the local linear frequency modulation spreading code. , represented as: ； 。

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