A method and system for tracking spread spectrum signals

Abstract

This application discloses a method and system for tracking spread spectrum signals, belonging to the field of signal processing. This application generates a spread spectrum digital signal by oversampling the acquired spread spectrum modulated signal. In-phase and quadrature components are generated by mixing, despreading, and coherent integration of this digital signal. Frequency and phase error information are calculated based on the components at continuous time intervals to correct the local carrier. The corrected local carrier is then used to mix the signal to baseband. An adjustable fractional delay is applied, and the instantaneous correlation energy peak is searched to determine the target fractional delay, thereby obtaining code phase error information. After correcting the local pseudocode using this code phase error information, the corrected local carrier and local pseudocode are used to initialize a narrow-bandwidth frequency-locked loop, phase-locked loop, and delay-locked loop, thus initiating precise tracking. This enables high-precision and stable locking of the spread spectrum signal in a short time.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of signal processing, and particularly relates to a spread spectrum signal tracking method and system. BACKGROUND

[0002] Spread spectrum communication technology has an important role in modern wireless communication, satellite navigation and measurement and control fields due to its excellent anti-interference, anti-multipath and low probability of interception and other characteristics. Whether the receiver can quickly acquire and stably track weak spread spectrum signals is a key link to determine the system performance, especially in the scene of processing burst signals or rapidly changing channel environment, the rapidity and accuracy of signal tracking have higher requirements, therefore, a fast and accurate spread spectrum signal tracking method has broad application prospects.

[0003] At present, the widely used technology in the field of spread spectrum signal tracking is a closed-loop feedback system composed of phase-locked loop, frequency-locked loop and delay-locked loop. The spread spectrum signal tracking method in the prior art mainly acquires the signal quickly by setting a wideband auxiliary channel, and then switches to a narrowband main channel for accurate tracking after locking, and the core idea is to accelerate the initial convergence process through a wideband loop.

[0004] However, the method of the prior art faces an inherent technical contradiction when dealing with the rapid tracking demand of burst signals. In order to pursue fast convergence, a wider loop bandwidth must be used, but this inevitably sacrifices the steady-state accuracy and anti-noise performance of tracking, resulting in that the final tracking accuracy cannot meet the requirements in precise measurement and high-quality communication applications. On the contrary, if a narrow-band loop is used to ensure high accuracy, the convergence time of the loop will become too long to meet the real-time requirements of burst signal processing. Therefore, the prior art has the problem that it is difficult to achieve stable locking of spread spectrum signals with high accuracy in a short time. SUMMARY

[0005] The present application provides a fast and accurate spread spectrum signal tracking method, system, device and computer storage medium, which can achieve stable locking of spread spectrum signals with high accuracy in a short time.

[0006] In a first aspect, the present application provides a fast and accurate spread spectrum signal tracking method, which comprises:

[0007] Acquire a spread spectrum modulated signal and oversample the spread spectrum modulated signal at a preset sampling rate to generate a spread spectrum digital signal comprising a plurality of sampling points in each chip period;

[0008] Mix the spread spectrum digital signal with a local carrier, and despread and coherent integrate the mixed spread spectrum digital signal using a local pseudo code to generate in-phase and quadrature components;

[0009] The frequency error information and the phase error information are calculated based on the in-phase component and the quadrature component at continuous time points, and the local carrier is corrected in frequency and phase by using the frequency error information and the phase error information, so as to obtain a corrected local carrier;

[0010] The spread spectrum digital signal is mixed with the corrected local carrier to obtain a baseband signal, an adjustable fractional delay is applied to the baseband signal, and the target fractional delay is determined by calculating the instantaneous correlation energy under different fractional delays, so as to obtain the code phase error information;

[0011] The local pseudo code is corrected by using the code phase error information, so as to obtain a corrected local pseudo code, and the narrow bandwidth frequency locked loop, phase locked loop and delay locked loop are initialized by using the corrected local carrier and the corrected local pseudo code, and then the spread spectrum modulated signal is tracked.

[0012] In an implementable embodiment, the spread spectrum modulated signal is obtained and oversampled at a preset sampling rate to generate a spread spectrum digital signal including a plurality of sampling points in each chip period, including:

[0013] The two orthogonal polarization components of the spread spectrum modulated signal are synchronously obtained, and the two orthogonal polarization components are respectively oversampled at a preset sampling rate to generate a first spread spectrum digital signal and a second spread spectrum digital signal including a plurality of sampling points in each chip period;

[0014] Before mixing the spread spectrum digital signal with the local carrier, the method further includes:

[0015] Based on the first spread spectrum digital signal and the second spread spectrum digital signal, the Stokes parameters are calculated;

[0016] According to the Stokes parameters, the first spread spectrum digital signal and the second spread spectrum digital signal are subjected to polarization synthesis processing to generate a target spread spectrum digital signal;

[0017] In the mixing of the spread spectrum digital signal with the local carrier, the spread spectrum digital signal is the target spread spectrum digital signal.

[0018] In an implementable embodiment, according to the Stokes parameters, the first spread spectrum digital signal and the second spread spectrum digital signal are subjected to polarization synthesis processing to generate a target spread spectrum digital signal, including:

[0019] The azimuth angle information and the ellipticity angle information representing the polarization state of the received signal are extracted from the Stokes parameters, and a polarization correction operator in complex form is generated based on the azimuth angle information and the ellipticity angle information according to a preset reference polarization state;

[0020] The first spread spectrum digital signal is taken as a first input, the second spread spectrum digital signal is taken as a second input, and the first input and the second input are combined together to form a dual-channel complex signal;

[0021] The double-channel complex signal is subjected to matrix multiplication with the polarization correction operator to obtain a corrected complex signal, and the two channels of the complex signal are merged to generate a target spread spectrum digital signal.

[0022] In an implementable embodiment, the local carrier includes an in-phase local carrier signal and a quadrature local carrier signal; the spread spectrum digital signal is mixed using the local carrier, and the mixed spread spectrum digital signal is despread and coherent integration calculated using the local pseudo code to generate in-phase components and quadrature components, including:

[0023] The spread spectrum digital signal is multiplied point by point with the in-phase local carrier signal to obtain a first mixed signal, and the spread spectrum digital signal is multiplied point by point with the quadrature local carrier signal to obtain a second mixed signal;

[0024] The first mixed signal is multiplied point by point with the local pseudo code to obtain a first despread signal, and the second mixed signal is multiplied point by point with the local pseudo code to obtain a second despread signal;

[0025] Within a preset coherent integration time length, all sample values of the first despread signal are accumulated and summed to obtain in-phase components, and all sample values of the second despread signal are accumulated and summed to obtain quadrature components.

[0026] In an implementable embodiment, based on the in-phase components and the quadrature components at consecutive time points, frequency error information and phase error information are calculated, and the local carrier is frequency and phase corrected using the frequency error information and the phase error information to obtain a corrected local carrier, including:

[0027] The frequency error information is generated by calculating a plurality of instantaneous frequency deviation values within a preset statistical period and performing arithmetic averaging, wherein each instantaneous frequency deviation value is obtained by cross-multiplying, dot product operation and arctangent operation on a group of in-phase components and quadrature components obtained at consecutive time points within the preset statistical period;

[0028] The frequency of the local carrier is corrected using the frequency error information;

[0029] The phase error information is generated by calculating a plurality of instantaneous phase deviation values within a next preset statistical period and performing arithmetic averaging, wherein each instantaneous phase deviation value is obtained by arctangent operation on a group of in-phase components and quadrature components obtained at consecutive time points within the next preset statistical period;

[0030] The phase of the frequency-corrected local carrier is corrected using the phase error information to obtain a corrected local carrier.

[0031] In one feasible implementation, a baseband signal is obtained by mixing the spread spectrum digital signal with a corrected local carrier. An adjustable fractional delay is applied to the baseband signal, and the target fractional delay is determined by calculating the instantaneous correlation energy under different fractional delays, thereby obtaining code phase error information, including:

[0032] The spread spectrum digital signal is mixed using a corrected local carrier to generate a complex baseband signal;

[0033] Set a search interval for fractional delay, and iteratively perform the following operations through an adjustable fractional delay digital filter: apply a fractional delay selected within the search interval to the baseband signal to generate a delayed baseband signal, and perform correlation integration operation between the delayed baseband signal and the instantaneous code of the local pseudocode to generate the instantaneous correlation energy corresponding to the selected fractional delay.

[0034] Based on the instantaneous relevance energy, adjust the selected score delay within the search interval for the next iteration until the instantaneous relevance energy reaches a peak.

[0035] The fractional delay corresponding to the peak value of the instantaneous correlation energy is determined as the target fractional delay, and the target fractional delay is used as the code phase error information.

[0036] In one feasible implementation, the local pseudocode is corrected using code phase error information to obtain a corrected local pseudocode. After initializing the narrow-bandwidth frequency-locked loop, phase-locked loop, and delay-locked loop using the corrected local carrier and the corrected local pseudocode, the spread spectrum modulation signal is tracked, including:

[0037] Based on the code phase error information, a phase control word for a numerically controlled oscillator is determined to generate a corrected local pseudo-code that is aligned with the code phase of the spread spectrum digital signal.

[0038] The frequency parameters of the local carrier correction are set as the initial state parameters of the narrow-bandwidth frequency-locked loop, and the phase parameters of the local carrier correction are set as the initial state parameters of the narrow-bandwidth phase-locked loop.

[0039] The phase parameters of the local pseudocode correction are set as the initial state parameters of the narrow-bandwidth delay-locked loop, and the frequency-locked loop, phase-locked loop, and delay-locked loop are started to perform closed-loop tracking of the spread spectrum modulation signal.

[0040] Secondly, this application provides a fast and accurate tracking system for spread spectrum signals, the system comprising:

[0041] The acquisition module is used to acquire the spread spectrum modulation signal and oversample the spread spectrum modulation signal at a preset sampling rate to generate a spread spectrum digital signal including multiple sampling points in each chip period.

[0042] The calculation module is used to mix the spread spectrum digital signal using the local carrier and to despread and perform coherent integration calculation on the mixed spread spectrum digital signal using the local pseudocode to generate in-phase and quadrature components.

[0043] The correction module is used to calculate frequency error information and phase error information based on the in-phase and quadrature components at continuous time intervals, and to use the frequency error information and phase error information to perform frequency and phase correction on the local carrier to obtain the corrected local carrier.

[0044] The delay module is used to mix the spread spectrum digital signal with the corrected local carrier to obtain the baseband signal, apply an adjustable fractional delay to the baseband signal, and determine the target fractional delay by calculating the instantaneous correlation energy under different fractional delays, thereby obtaining code phase error information.

[0045] The tracking module is used to correct the local pseudocode using code phase error information to obtain the corrected local pseudocode. After initializing the narrow-bandwidth frequency-locked loop, phase-locked loop, and delay-locked loop using the corrected local carrier and the corrected local pseudocode, it tracks the spread spectrum modulation signal.

[0046] Thirdly, this application provides an electronic device, the device including: a processor, and a memory storing computer program instructions; the processor reads and executes the computer program instructions to implement the fast and accurate tracking method of spread spectrum signals as in any embodiment of the first aspect.

[0047] Fourthly, this application provides a computer-readable storage medium storing computer program instructions, which, when executed by a processor, implement a fast and accurate tracking method for spread spectrum signals as described in any embodiment of the first aspect.

[0048] This application discloses a fast and accurate tracking method, system, device, and computer storage medium for spread spectrum signals. First, it provides a high-resolution digital signal foundation by oversampling the received signal. Then, an open-loop pre-correction stage is introduced before closed-loop tracking. By analyzing the in-phase and quadrature components at consecutive time points, the initial frequency and phase errors of the carrier are accurately estimated and compensated. Furthermore, fractional delay technology is used to perform fine correction of the code phase error at the sub-sampling interval level, overcoming the physical limitation of hardware sampling rate on ranging accuracy. Through these pre-correction steps, the frequency, phase, and code phase mismatch between the local signal and the received signal are minimized before the closed-loop tracking loop is initiated. Therefore, this application can achieve both fast convergence and high-precision stable tracking of burst spread spectrum signals using an extremely narrow loop bandwidth without sacrificing noise immunity.

[0049] Furthermore, in the initial stage of signal processing, the two orthogonal polarization components of the signal are simultaneously acquired using a dual-polarized antenna, and Stokes parameters that can fully describe the signal's polarization state are calculated based on these components. This allows the receiver to perceive polarization distortion caused by path effects such as reflection and scattering in real time, rather than making pre-assumptions about the signal's polarization. Based on this, by performing polarization synthesis on the two orthogonal polarization components, the signal energy of any received polarization state can be optimally aggregated, thereby maximizing the recovery of signal power lost due to polarization mismatch before entering subsequent frequency, phase, and code phase correction processes. This not only improves the effective signal-to-noise ratio but also enhances the method's adaptability to complex channel environments from a physical perspective, improving the stability and accuracy of high-precision tracking of spread spectrum signals. Attached Figure Description

[0050] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0051] Figure 1 This is a flowchart illustrating a fast and accurate tracking method for spread spectrum signals provided in one embodiment of this application;

[0052] Figure 2 This is a flowchart illustrating a method for generating a target spread spectrum digital signal according to an embodiment of this application;

[0053] Figure 3 This is a flowchart illustrating a method for determining code phase error information according to an embodiment of this application;

[0054] Figure 4 This is a schematic diagram of the structure of a fast and accurate tracking system for spread spectrum signals provided in one embodiment of this application;

[0055] Figure 5 This is a schematic diagram of the hardware structure of an electronic device provided in one embodiment of this application. Detailed Implementation

[0056] The features and exemplary embodiments of various aspects of this application will be described in detail below. To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain this application and not to limit it. For those skilled in the art, this application can be implemented without some of these specific details. The following description of the embodiments is merely to provide a better understanding of this application by illustrating examples.

[0057] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes said element.

[0058] Currently, the widely used technology in spread spectrum signal tracking is a closed-loop feedback system composed of phase-locked loops, frequency-locked loops, and delay-locked loops. Existing spread spectrum signal tracking methods mainly use a broadband auxiliary channel to quickly acquire the signal, and then switch to a narrowband main channel for precise tracking after locking. The core idea is to accelerate the initial convergence process through a broadband loop.

[0059] However, existing methods face an inherent technical contradiction when dealing with the rapid tracking requirements of burst signals. To achieve rapid convergence, a wider loop bandwidth is necessary, but this inevitably sacrifices steady-state tracking accuracy and noise immunity, resulting in substandard tracking accuracy in precision measurement and high-quality communication applications. Conversely, if a narrow-band loop is used to ensure high accuracy, the loop convergence time becomes excessively long, failing to meet the real-time requirements of burst signal processing. Therefore, existing technologies struggle to achieve high-precision, stable locking of spread spectrum signals within a short timeframe.

[0060] To address the problems of the prior art, embodiments of this application provide a method, system, device, and computer storage medium for fast and accurate tracking of spread spectrum signals. The fast and accurate tracking method for spread spectrum signals provided in this application embodiment will be described first below.

[0061] Figure 1 A flowchart illustrating a fast and accurate tracking method for spread spectrum signals according to an embodiment of this application is shown. Figure 1 As shown, the method includes steps S110 to S150.

[0062] S110: Acquire the spread spectrum modulation signal and oversample the spread spectrum modulation signal at a preset sampling rate to generate a spread spectrum digital signal including multiple sampling points in each chip period.

[0063] Spread spectrum modulation signals are wireless signals modulated using direct sequence spread spectrum technology, and their spectral bandwidth is much larger than the original information bandwidth. The signal form is the product of a carrier wave and a pseudo-random code. A spread spectrum modulated signal can be expressed as r(t) = D(t)P(t)cos(2πf) c t+φ0), where r(t) represents the spread spectrum modulation signal, D(t) is a binary data sequence with a value of ±1, P(t) is a pseudo-random code with a value of ±1, and f c φ0 is the carrier frequency, and φ0 is the initial phase. Oversampling refers to sampling an analog signal at a frequency higher than the Nyquist sampling rate. The number of sampling points N in each chip period is determined by the sampling rate f. s and pseudo-code chip rate R c Determined, the specific relationship is f s =N×R c Where N is an integer much greater than 2, for example, N≥10, to achieve high-rate oversampling and thus obtain high-resolution digital signals. The data structure is a time sequence s[k]=r(kT) s ), T s Sampling interval T s =1 / f s k is the sampling index.

[0064] First, the spread spectrum modulated signal r(t) received by the antenna is processed by an RF front-end circuit, which performs low-noise amplification, bandpass filtering, and down-conversion to convert the high-frequency RF signal into an intermediate-frequency analog signal. At this time, the signal form remains unchanged, only the carrier frequency f changes. c The frequency is then reduced to an intermediate frequency. Subsequently, an analog-to-digital converter (ADC) operates according to a preset sampling rate f. s The intermediate frequency analog signal is sampled. The sampling rate f s The setting is much larger than the pseudo-code chip rate R. c Twice that of the pseudo-code chip rate to meet the oversampling requirements. For example, if the pseudo-code chip rate R c The preset sampling rate is 1.023 Mcps. s If the frequency can be set to 20.46MHz, then the number of sampling points N in each chip cycle is 20. The ADC quantizes the intermediate frequency analog signal once in each sampling interval Ts, and the output discrete time sequence s[k] is the spread spectrum digital signal. When this discrete time sequence s[k] is processed, it will be buffered in the form of data blocks. For example, a data block containing M samples can be represented in memory as an array {s[0],s[1],...,s[M-1]}, where every N consecutive samples, such as from s[0] to s

[19] , correspond to the first chip cycle.

[0065] S120: Mix the spread spectrum digital signal using the local carrier, and use the local pseudocode to despread and perform coherent integration calculation on the mixed spread spectrum digital signal to generate in-phase and quadrature components.

[0066] The local carrier refers to the reference signal generated inside the receiver by a numerically controlled oscillator (NCO) for frequency and phase comparison with the input signal. It includes in-phase local carrier signals and quadrature local carrier signals, which are orthogonal in phase. The local pseudocode refers to the reference code sequence generated inside the receiver, which has the same structure as the pseudo-random code sequence used at the transmitter. The in-phase and quadrature components are the two DC component values ​​obtained in the in-phase and quadrature branches, respectively, of the spread spectrum digital signal after mixing, despreading, and coherent integration.

[0067] First, the acquired spread spectrum digital signal sequence s[k] is input into a digital multiplier, and mixing is performed using the in-phase branch (I branch) and quadrature branch (Q branch) alignment of the local carrier. On the I branch, s[k] is multiplied point-by-point with the in-phase local carrier signal to complete in-phase mixing; simultaneously, on the Q branch, the spread spectrum digital signal sequence s[k] is multiplied point-by-point with the quadrature local carrier signal to complete quadrature mixing. For example, if the intermediate frequency generated in S110 is 5.42MHz, then the local carrier I branch can be: cos(2π×5.42e6×t), and the Q branch can be: -sin(2π×5.42e6×t). Next, the signals after mixing on the I and Q branches are multiplied point-by-point with the local pseudocode to complete the despreading operation. The local pseudocode is a preset pseudo-random code sequence consistent with the transmitter, with a chip rate of R. c The chip value of the local pseudocode is repeated N times within each chip period to match the oversampling rate of the spread spectrum digital signal. Finally, within a preset coherent integration time, such as the duration of one data bit, the despread signal sample values ​​of the I-branch and Q-branch are coherently integrated and accumulated. The result of the coherent integration accumulation of the I-branch is the in-phase component, and the result of the coherent integration accumulation of the Q-branch is the quadrature component; the in-phase component and the quadrature component are the coherent integration values ​​of the I-branch and Q-branch based on subsequent error calculations.

[0068] S130: Based on the in-phase and quadrature components at continuous time intervals, calculate the frequency error information and phase error information, and use the frequency error information and phase error information to perform frequency and phase correction on the local carrier to obtain the corrected local carrier.

[0069] Frequency error information refers to a quantified value characterizing the frequency difference between the local carrier and the input signal carrier, used to adjust the generation frequency of the local carrier. Phase error information refers to a quantified value characterizing the static phase difference between the local carrier and the input signal carrier, used to adjust the initial phase of the local carrier. In-phase and quadrature components at consecutive moments refer to two sets of in-phase and quadrature components calculated separately over two adjacent coherent integration times. A corrected local carrier refers to a new local carrier signal whose frequency and phase have been adjusted to achieve high alignment with the carrier frequency and phase of the input signal.

[0070] This process is divided into two stages. The first stage is frequency correction: using I obtained at two consecutive moments. p (n-1), I p (n) and orthogonal component Q p (n-1), Q p (n) is used to calculate an instantaneous frequency deviation value f through cross-multiplication, dot product, and arctangent operations. e To improve accuracy, this process is repeated within a preset statistical period to obtain multiple instantaneous frequency deviation values ​​f. e Then, these values ​​are arithmetically averaged to obtain the final frequency error information Δf. e Subsequently, the frequency error information Δf e This is used to adjust the frequency control word of the local carrier generation circuit. The second stage is phase correction: after the local carrier frequency is corrected, a new set of in-phase components I is obtained. p (n) and orthogonal component Q p (n). Since the frequency difference is now extremely small, it is only necessary to adjust this pair of new I... p (n) and Q p By performing an arctangent operation on the value of (n), an instantaneous phase deviation value can be obtained. Similarly, by repeatedly calculating and applying multiple instantaneous phase deviation values... The arithmetic mean is then calculated to obtain the final phase error information. This information is used to adjust the phase control word of the local carrier. After completing both frequency and phase corrections, the resulting local carrier is the corrected one.

[0071] S140: The spread spectrum digital signal is mixed using a corrected local carrier to obtain a baseband signal. An adjustable fractional delay is applied to the baseband signal, and the target fractional delay is determined by calculating the instantaneous correlation energy under different fractional delays, thereby obtaining code phase error information.

[0072] Instantaneous correlation energy refers to the energy value obtained by correlating the instantaneous code components of the local pseudocode with a baseband signal that has been subjected to a specific fractional delay. The magnitude of the energy value indicates the degree of code phase alignment. The target fractional delay refers to the optimal fractional delay value that allows the instantaneous correlation energy to reach its peak. Code phase error information is a quantified value characterizing the phase difference between the local pseudocode and the input signal pseudocode.

[0073] First, the acquired spread spectrum digital signal is mixed using a corrected local carrier to generate a complex baseband signal. The baseband signal is the complex signal obtained by shifting the spectrum of the spread spectrum digital signal to near zero frequency after mixing with the corrected local carrier. Then, an iterative optimization algorithm is used to determine the target fractional delay. This algorithm applies different fractional delays τ to the baseband signal within a preset search interval using an adjustable fractional delay digital filter. The adjustable fractional delay refers to a time delay smaller than a single sampling interval that can be precisely controlled by the digital algorithm. For example, the digital filter can be a Farrow filter, where the fractional delay is changed by adjusting its polynomial coefficients. For each applied fractional delay, its corresponding instantaneous correlation energy P(τ) is calculated. By comparing the instantaneous correlation energy under different fractional delays, the algorithm gradually adjusts the applied fractional delay to approach the peak energy point. For example, a gradient ascent method can be used, calculating the gradient direction based on the energy values ​​of the current point and neighboring points, and then adjusting the delay along the gradient direction for the next adjustment. When the iterative process converges, that is, when the correlation energy reaches its maximum value, the applied fractional delay at this point is determined as the target fractional delay. Ultimately, this target fractional delay is used as the code phase error information.

[0074] S150: The local pseudocode is corrected using code phase error information to obtain the corrected local pseudocode. After the corrected local carrier and the corrected local pseudocode are used to initialize the narrow-bandwidth frequency-locked loop, phase-locked loop and delay-locked loop, the spread spectrum modulation signal is tracked.

[0075] A frequency-locked loop (FLL) is a feedback circuit that synchronizes the locally generated carrier signal with the carrier of the input signal in frequency. A phase-locked loop (PLL) is a feedback circuit that synchronizes the locally generated carrier signal with the carrier of the input signal in phase. A delay-locked loop (DLL) is a feedback circuit whose main function is to keep the locally generated pseudocode consistent with the pseudocode in the input signal in code phase. This embodiment uses narrow bandwidth, meaning these loops are configured with narrow loop filter bandwidth, thus achieving high accuracy and strong noise immunity.

[0076] First, the obtained code phase error information is used to correct the local pseudocode generation process. For example, a code phase error of 0.236 sampling intervals is converted into a specific phase adjustment value and used to update the phase control word of the numerically controlled oscillator (NCO) in the local pseudocode generation circuit, generating a corrected local pseudocode. A corrected local pseudocode refers to a new local pseudocode sequence whose code phase has been precisely adjusted to achieve high-precision alignment with the pseudocode phase of the input signal. Subsequently, the tracking loop is initialized, the core of which is to use pre-corrected parameters to set precise initial operating points for each loop. Specifically, the frequency parameters of the generated corrected local carrier are loaded into the FLL to ensure its initial frequency is essentially consistent with the input signal frequency; the phase parameters of the corrected local carrier are loaded into the PLL to ensure its initial phase is essentially consistent with the input signal phase; and the phase parameters of the corrected local pseudocode are loaded into the DLL to ensure its initial code phase is essentially consistent with the input signal code phase. Finally, with the initial errors of all loops pre-compensated to a minimum, the narrow-bandwidth FLL, PLL, and DLL are activated to begin stable and accurate closed-loop tracking of the spread spectrum modulation signal.

[0077] This embodiment provides a high-resolution digital signal foundation by oversampling the received signal. Subsequently, an open-loop pre-correction stage is introduced before closed-loop tracking. By analyzing the in-phase and quadrature components at consecutive moments, the initial frequency and phase errors of the carrier are accurately estimated and compensated. Furthermore, fractional delay technology is used to perform fine correction of the code phase error at the sub-sampling interval level, overcoming the physical limitation of hardware sampling rate on ranging accuracy. Through the above pre-correction steps, the frequency, phase, and code phase mismatch between the local signal and the received signal are eliminated to a minimum before the closed-loop tracking loop is activated. Therefore, this application can achieve both rapid convergence and high-precision stable tracking of burst spread spectrum signals using an extremely narrow loop bandwidth without sacrificing noise immunity.

[0078] In practical satellite navigation and communication scenarios, the polarization characteristics of spread spectrum signals change after penetrating tree canopies, clouds, or being reflected by buildings, leading to polarization mismatch with the receiving antenna. This can cause severe signal power attenuation, thereby deteriorating the signal-to-noise ratio of all subsequent signal processing stages and directly affecting the success rate and accuracy of tracking. This application addresses the above problems through the following technical solution.

[0079] In one feasible implementation, step S110: acquiring the spread spectrum modulation signal and oversampling the spread spectrum modulation signal at a preset sampling rate to generate a spread spectrum digital signal including multiple sampling points in each chip period, including:

[0080] The two orthogonal polarization components of the spread spectrum modulation signal are acquired synchronously, and the two orthogonal polarization components are oversampled at a preset sampling rate to generate a first spread spectrum digital signal and a second spread spectrum digital signal including multiple sampling points in each chip period.

[0081] Two orthogonal polarization components refer to the projection components of the electric field vector of an electromagnetic wave in two mutually perpendicular directions during propagation. For example, they can be the horizontal polarization component H and the vertical polarization component V, or the right-hand circular polarization component RHCP and the left-hand circular polarization component LHCP. The first spread spectrum digital signal s1[k] and the second spread spectrum digital signal s2[k] are two parallel discrete-time sequences obtained by independently oversampling and digitizing the two orthogonal polarization components, respectively, where k is the sampling index.

[0082] Two orthogonal polarization components can be simultaneously acquired using a dual-polarized antenna with two mutually orthogonal feeds, capable of simultaneously sensing and outputting analog voltage signals corresponding to the two orthogonal polarization components. These two analog signals are then fed into a dual-channel RF front-end for parallel low-noise amplification, filtering, and down-conversion. For example, an RHCP signal with a center frequency of 1.575 GHz and an LHCP signal of the same frequency are simultaneously down-converted to an intermediate frequency of 5.42 MHz. Next, two synchronously operating analog-to-digital converters (ADCs) are used, each sampling at the same preset sampling rate f. s The two intermediate frequency analog signals are sampled and quantized to generate a first spread spectrum digital signal s1[k] and a second spread spectrum digital signal s2[k] in discrete time series form, respectively.

[0083] Before mixing the spread spectrum digital signal using a local carrier in step S120, the method further includes:

[0084] Based on the first and second spread-spectrum digital signals, the Stokes parameters are calculated. The Stokes parameters are a vector consisting of four real numbers, I, Q, U, and V, used to fully describe the polarization state of the electromagnetic wave. Parameter I represents the total intensity, parameters Q and U describe the direction and magnitude of the linear polarization component, and parameter V describes the degree and direction of rotation of the circular polarization component.

[0085] First, a preliminary baseband conversion is required for the first spread spectrum digital signal s1[k] and the second spread spectrum digital signal s2[k] to obtain their complex baseband representations, E1[k] and E2[k], respectively. Then, the Stokes parameters are calculated by statistically averaging these two complex signals within a preset time window, for example, 1 millisecond. This calculation process is a well-known technique in the field. In short, parameter I is obtained by summing the energies of the two signals; parameter Q is obtained by the energy difference between the two signals; and parameters U and V are obtained by calculating the real and imaginary parts of the cross-correlation result of the two signals, respectively.

[0086] Based on the Stokes parameters, the first spread spectrum digital signal and the second spread spectrum digital signal are polarized and synthesized to generate the target spread spectrum digital signal.

[0087] Polarization synthesis refers to generating a new signal by performing a complex weighted summation of the first spread spectrum digital signal s1[k] and the second spread spectrum digital signal s2[k]. The target spread spectrum digital signal s t [k] is the final output signal obtained after polarization synthesis, whose polarization state is optimized, for example, to match the local reference polarization, thereby maximizing the signal energy.

[0088] Based on the calculated Stokes parameters I, Q, U, and V, the polarization state of the currently received signal can be obtained. A reference polarization state is also preset; for example, for navigation signals, the reference polarization state is typically pure right-hand circular polarization. By comparing the current Stokes parameters with the reference Stokes parameters, a complex polarization correction operator can be calculated. This operator can be a 2x2 matrix containing complex weights for rotating and adjusting the polarization ellipse. Applying this operator to the first spread spectrum digital signal s1[k] and the second spread spectrum digital signal s2[k] yields the target spread spectrum digital signal s. t [k].

[0089] In the mixing of spread spectrum digital signals using a local carrier, the spread spectrum digital signal is the target spread spectrum digital signal. The channel component corresponding to the reference polarization (RHCP) in this signal is extracted as the final target spread spectrum digital signal s. t [k]. This target spread-spectrum digital signal s will be used in all subsequent processing steps. t [k] is used as input to replace the original single-channel spread spectrum digital signal.

[0090] For example, in an application scenario of a vehicle-mounted satellite navigation receiver, the vehicle is driving in an urban canyon area, and the pseudo-code chip rate R of the spread spectrum modulation signal received by the antenna is... c The sampling rate is 1.023 Mcps. To address the polarization mismatch caused by signal reflection and scattering, the receiver employs a dual circularly polarized antenna to simultaneously acquire the right-hand circularly polarized (RHCP) and left-hand circularly polarized (LHCP) components of the spread spectrum modulated signal, and down-converts them to an intermediate frequency of 5.42 MHz. Subsequently, two synchronized ADCs operate at a preset sampling rate f. sThe two intermediate frequency (IF) signals are sampled at 20.46 MHz to generate a first spread spectrum digital signal s1[k] and a second spread spectrum digital signal s2[k] containing 20 sampling points per chip period. Before entering the mixing process in step S120, the digital signal processor first performs polarization domain preprocessing on these two signals. Within a 1-millisecond time window, the processor calculates the Stokes parameter vector characterizing the complete polarization state of the current received signal by performing statistical operations on the complex baseband form of the two signals. For example, it obtains {I = 1.0, Q = 0.2, U = 0.3, V = 0.6}, which indicates that the received signal has deviated from the ideal pure RHCP state.

[0091] Based on the calculated Stokes parameters, polarization synthesis is performed to generate a target spread spectrum digital signal with optimal energy. The preset reference polarization state is pure RHCP, with ideal Stokes parameters of {1,0,0,1}. By comparing the difference between the measured Stokes parameters and this reference state, the system calculates a 2x2 complex polarization correction operator, such as [[0.9,-0.1j],[0.1j,0.8]]. This operator contains the complex weights required to correct the polarization state of the current received signal back to the reference state. Subsequently, the processor combines the first spread spectrum digital signal s1[k] and the second spread spectrum digital signal s2[k] into a dual-channel complex signal and performs matrix multiplication with the polarization correction operator. The result of the operation is a corrected dual-channel complex signal. The channel component corresponding to the reference polarization (RHCP) is extracted from this signal and used as the final target spread spectrum digital signal st[k]. This st[k] will then replace the original single-channel signal as the input to the mixing process in step S120. Since its signal energy is maximized, the signal-to-noise ratio of the subsequent tracking process is significantly improved.

[0092] Figure 2 A flowchart illustrating a method for generating a target spread spectrum digital signal according to an embodiment of this application is shown. Figure 2 As shown, the method includes steps S210 to S230.

[0093] In one feasible implementation, the first spread spectrum digital signal and the second spread spectrum digital signal are polarized and combined according to Stokes parameters to generate the target spread spectrum digital signal, including:

[0094] S210: Extract azimuth and elliptic angle information representing the polarization state of the received signal from the Stokes parameters, and generate a complex polarization correction operator based on the azimuth and elliptic angle information according to the preset reference polarization state.

[0095] Azimuth angle and ellipticity angle are two parameters used to geometrically describe the polarization ellipse. Azimuth angle indicates the tilt angle of the major axis of the polarization ellipse relative to the horizontal direction of the reference coordinate system. Ellipticity angle describes the flattening of the polarization ellipse, with its sign indicating the direction of rotation of the electric field vector. The preset reference polarization state is the ideal polarization form that the receiver expects to recover from the signal, such as pure right-hand circular polarization.

[0096] First, based on the Stokes parameters I, Q, U, and V, azimuth and elliptic angle information are extracted using standard trigonometric function operations. For example, if the calculated Stokes parameters are {I = 1.0, Q = 0.2, U = 0.3, V = 0.6}, then the azimuth angle is approximately 28.1 degrees by performing arctangent operations on U and Q, and the elliptic angle is approximately 18.4 degrees by performing arcsine operations on V and I. Simultaneously, a reference polarization state is set according to application requirements, and its corresponding reference azimuth and reference elliptic angle are determined. For example, the preset reference polarization state is ideal right-hand circular polarization RHCP. The reference azimuth angle corresponding to this state can be set to any value, typically 0 degrees, while its reference elliptic angle is fixed at 45 degrees. Subsequently, the differences between the measured azimuth and elliptic angles and the reference azimuth and reference elliptic angles are calculated. Finally, these angular differences are substituted into a pre-defined mathematical model, such as the formula for constructing the Jones matrix, to generate a 2x2 polarization correction operator containing four complex elements. Specifically, based on the measured azimuth and elliptic angle differences, a polarization correction operator is constructed using a pre-defined Jones matrix model. This operator is a 2×2 complex matrix whose element values ​​are jointly determined by the azimuth and elliptic angle differences. The real elements in the matrix primarily compensate for the linear polarization rotation caused by the azimuth deviation, while the imaginary elements are used to correct the circular polarization component distortion caused by the elliptic angle difference. This ultimately generates a 2x2 complex matrix containing four complex elements, i.e., the polarization correction operator.

[0097] S220: The first spread spectrum digital signal is used as the first input, and the second spread spectrum digital signal is used as the second input, which are combined to form a dual-channel complex signal.

[0098] The complex baseband sample value s1[k] of the first spread spectrum digital signal at the same sampling time k is taken as the first element of the dual-channel complex signal vector; simultaneously, the complex baseband sample value s2[k] of the second spread spectrum digital signal is taken as the second element of the vector. For example, at a certain sampling time k, if the complex baseband value of s1[k] is 1.2+0.3j and the complex baseband value of s2[k] is 0.4-0.1j, then the dual-channel complex signal vector generated at that time is [1.2+0.3j; 0.4-0.1j], where j is the imaginary unit. In this way, a two-dimensional complex vector is formed for each sampling time k.

[0099] S230: Perform matrix multiplication on the dual-channel complex signal and the polarization correction operator to obtain the corrected complex signal, and merge the two channels of the complex signal to generate the target spread spectrum digital signal.

[0100] The 2x2 polarization correction operator generated in S210 is multiplied by a matrix with the dual-channel complex signal vector at time k generated in S220. For example, a 2x2 polarization correction operator [[0.9,-0.1j],[0.1j,0.8]] is multiplied by a dual-channel complex signal vector with elements [1.2+0.3j; 0.4-0.1j], where j is the imaginary unit. This yields a 2x1 corrected complex signal vector. Subsequently, the target spread spectrum digital signal is generated according to a preset merging strategy. If the reference polarization state is right-hand circular polarization, the first element corresponding to the right-hand circular polarization channel in the corrected complex signal vector is directly extracted as the target spread spectrum digital signal sample value s at sampling time k. t [k], target spread spectrum digital signal s t [k] is the input in the subsequent signal processing steps, namely the spread spectrum digital signal sequence s[k].

[0101] In the initial stage of signal processing, this embodiment synchronously acquires two orthogonal polarization components of the signal using a dual-polarized antenna and calculates Stokes parameters that fully describe the signal's polarization state. This allows the receiver to perceive polarization distortion caused by path effects such as reflection and scattering in real time, rather than making pre-assumptions about the signal's polarization. Furthermore, by performing polarization synthesis on the two orthogonal polarization components, the energy of the received signal in any polarization state can be optimally aggregated. This maximizes the recovery of signal power lost due to polarization mismatch before proceeding to subsequent frequency, phase, and code phase correction processes. This not only improves the effective signal-to-noise ratio but also enhances the method's adaptability to complex channel environments from a physical perspective, improving the stability and accuracy of high-precision tracking of spread spectrum signals.

[0102] In one feasible implementation, the local carrier includes an in-phase local carrier signal and a quadrature local carrier signal; the spread spectrum digital signal is mixed using the local carrier, and the mixed spread spectrum digital signal is despread and coherently integrated using local pseudocode to generate in-phase and quadrature components, including:

[0103] The spread spectrum digital signal is multiplied point by point with the in-phase local carrier signal to obtain the first mixed signal. At the same time, the spread spectrum digital signal is multiplied point by point with the quadrature local carrier signal to obtain the second mixed signal.

[0104] For each sample point in the spread spectrum digital signal sequence s[k], two multiplication operations are performed in parallel. The first multiplication multiplies s[k] with the corresponding sample of an in-phase local carrier signal generated by a numerically controlled oscillator (NCO), resulting in the first mixed signal. The second multiplication multiplies the same s[k] with the corresponding sample of an orthogonal local carrier signal generated by the same NCO, which is 90 degrees out of phase, resulting in the second mixed signal. The mixed in-phase branch signal can be represented as... Orthogonal branch signals can be represented as Where Δf and These represent the carrier frequency difference and phase difference, respectively. The carrier frequency is first compensated using a frequency estimation method to minimize Δf to near zero. Then, the carrier phase is compensated, even if... The value approaches 0 to reach its minimum, allowing the FLL and PLL to start operating with minimal initial error. The first mixed signal is multiplied point-by-point with the local pseudocode to obtain the first despread signal, and the second mixed signal is multiplied point-by-point with the local pseudocode to obtain the second despread signal.

[0105] Each sample in the first mixed signal sequence is multiplied point-by-point with the corresponding sample of a synchronously generated local pseudocode sequence P(t) to obtain the first despread signal. Simultaneously, each sample in the second mixed signal sequence is multiplied point-by-point with the corresponding sample of the same local pseudocode sequence P(t) to obtain the second despread signal. The local pseudocode is a pseudo-random code sequence consistent with the transmitter; its generated chip values ​​are repeated N times within each chip period to precisely align with the oversampled mixed signal sample points in time. For example, if the pseudocode chip rate R... c If the value is 1.023 Mcps and the oversampling factor N is 20, then the local pseudocode generator will continuously output its current chip value (+1 or -1) 20 times in each chip period, forming a local pseudocode sample sequence P(t) that is consistent with the input signal sample flow rate.

[0106] Within a preset coherent integration time, all sample values ​​of the first despread signal are summed to obtain the in-phase component, and all sample values ​​of the second despread signal are summed to obtain the quadrature component.

[0107] Within a preset coherent integration time T, all sample values ​​of the first despread signal are summed, and this final sum is the in-phase component. Simultaneously, within the exact same coherent integration time, all sample values ​​of the second despread signal are summed, and this sum is the quadrature component. This is in the presence of a frequency error f. e and phase error In the case of, the obtained in-phase component Ip (n) can be approximated as Orthogonal component Q p (n) can be approximated as Among them, I p (n) The integral value of the in-phase component in the nth integration period, Q p (n) is the integral value of the orthogonal component in the nth integration period, where A is the signal amplitude, which depends on the original signal power, the data bits D(n), and the pseudocode autocorrelation peak value R(τ), and T is the coherent integration duration. This represents the total effective phase error at the midpoint of the integration period.

[0108] In one feasible implementation, frequency error information and phase error information are calculated based on the in-phase and quadrature components at consecutive time points. The frequency error information and phase error information are then used to perform frequency and phase correction on the local carrier to obtain a corrected local carrier, including:

[0109] Frequency error information is generated by calculating multiple instantaneous frequency deviation values ​​within a preset statistical period and then performing an arithmetic average. Each instantaneous frequency deviation value is obtained by performing cross-multiplication, dot product, and arctangent operations on a set of in-phase and quadrature components acquired from consecutive moments within the preset statistical period. The frequency error information is then used to correct the frequency of the local carrier.

[0110] The instantaneous frequency deviation value is an estimate calculated within a single measurement period, reflecting the instantaneous frequency difference between the local carrier and the input signal carrier. The preset statistical period can be a set time period or the number of measurements. The frequency error information is the frequency difference measurement result obtained by arithmetically averaging multiple instantaneous frequency deviation values.

[0111] First, it is necessary to obtain the two sets of in-phase components I generated in S120 within two consecutive coherent integration times. p (n-1), I p (n) and orthogonal component Q p (n-1), Q p (n). Then, the instantaneous frequency deviation value f is calculated. e , specifically, f e =(atan(P) cross ,P dot )) / 2πT.

[0112] Among them, P cross =I p (n-1)Q p (n)-Q p (n-1)I p (n), P dot =I p(n-1)I p (n)+Q p (n-1)Q p (n); atan is the arctangent in the second quadrant, and T is the duration of a single coherent integral. Within a preset statistical period, for example, the calculation is repeated 10 times to obtain 10 instantaneous frequency deviation values ​​f. e Finally, the final frequency error information Δf is generated by taking the arithmetic mean of these 10 values. e And using this Δf e Adjust the frequency control word of the local carrier NCO to complete frequency correction.

[0113] Phase error information is generated by calculating multiple instantaneous phase deviation values ​​and performing an arithmetic mean within the next preset statistical period. Each instantaneous phase deviation value is obtained by performing an arctangent operation on a set of in-phase and quadrature components acquired from consecutive moments within the next preset statistical period. The phase error information is then used to correct the phase of the frequency-corrected local carrier, resulting in a corrected local carrier.

[0114] The instantaneous phase deviation value is an estimate of the static phase difference between the local carrier frequency and the input signal frequency, calculated within a single measurement cycle after they are substantially aligned. The next preset statistical cycle refers to a new measurement cycle set after frequency correction is completed to accurately estimate the phase. The phase error information is the phase difference measurement result obtained by arithmetically averaging multiple instantaneous phase deviation values.

[0115] After the local carrier frequency has been corrected in the previous step, the S120 procedure will be executed again to obtain a new set of in-phase components I under the current frequency alignment conditions. p (n) and orthogonal component Q p (n). Since the frequency difference Δf is now close to zero, complex cross-multiplication and dot product operations are no longer needed. This can be achieved directly by applying the new I... p (n) and Q p (n) Perform arctangent operation to calculate the instantaneous phase deviation value. Specifically Similarly, within a new statistical period, for example, by repeating the calculation 10 times, 10 instantaneous phase deviation values ​​are obtained. Finally, the arithmetic mean of these 10 values ​​is used to generate the final phase error information. And utilize this The phase control word of the local carrier NCO is adjusted to complete the phase correction, thereby obtaining the final corrected local carrier.

[0116] Figure 3 A flowchart illustrating a method for determining code phase error information according to an embodiment of this application is shown.Figure 3 As shown, the method includes steps S310 to S340.

[0117] In one feasible implementation, a baseband signal is obtained by mixing the spread spectrum digital signal with a corrected local carrier. An adjustable fractional delay is applied to the baseband signal, and the target fractional delay is determined by calculating the instantaneous correlation energy under different fractional delays, thereby obtaining code phase error information, including:

[0118] S310: Uses a corrected local carrier to perform mixing processing on the spread spectrum digital signal to generate a complex baseband signal.

[0119] The complex form of the baseband signal refers to the complex signal obtained by mixing the spread spectrum digital signal with a corrected local carrier whose frequency and phase have been corrected, and whose spectrum is completely shifted to near zero frequency.

[0120] Using the corrected local carrier finally generated in S130, the spread spectrum digital signal acquired in S110 is subjected to complex mixing. Specifically, the spread spectrum digital signal sequence s[k] is multiplied point-by-point by the in-phase component of the corrected local carrier to obtain the real part of the baseband signal; simultaneously, s[k] is multiplied point-by-point by the quadrature component of the corrected local carrier to obtain the imaginary part of the baseband signal. Since the frequency and phase of the corrected local carrier are highly aligned with the input signal, the baseband signal obtained after mixing is a complex sequence with concentrated energy.

[0121] S320: Set a search interval for a fractional delay, and iteratively perform the following operations through an adjustable fractional delay digital filter: apply a fractional delay selected within the search interval to the baseband signal to generate a delayed baseband signal, and perform correlation integration operation between the delayed baseband signal and the instantaneous code of the local pseudocode to generate the instantaneous correlation energy corresponding to the selected fractional delay.

[0122] An adjustable fractional delay digital filter is a signal processor capable of imposing a fine time delay of less than one sampling interval on a digital signal. The instantaneous code of the local pseudocode refers to a copy of the local pseudocode that should theoretically be perfectly aligned with the pseudocode of the input signal.

[0123] First, a search interval for the fractional delay is defined. This search interval is a preset range in units of sampling intervals, such as [-0.5, +0.5], used to limit the search range for code phase error. In each iteration of the loop, a fractional delay value τ is selected from this search interval. Subsequently, an adjustable fractional delay digital filter, such as a Farrow structure filter, is configured with corresponding filter coefficients to apply a delay of τ to the baseband signal, thereby generating a delayed baseband signal. The delayed baseband signal is the signal obtained after processing the original baseband signal through this digital filter. Next, this delayed baseband signal is correlated and integrated with the instantaneous code of the local pseudocode. The integration time is typically one pseudocode period, and the energy of the result is calculated as the instantaneous correlation energy P(τ) corresponding to the fractional delay τ. The instantaneous correlation energy is the energy value obtained after correlating and integrating the delayed baseband signal with the instantaneous code.

[0124] S330: Based on the instantaneous correlation energy, adjust the selected fraction delay within the search interval for the next iteration until the instantaneous correlation energy reaches a peak.

[0125] Adjusting the fractional delay selected for the next iteration refers to using an optimization algorithm to determine the fractional delay value to be tested in the next iteration based on the instantaneous correlation energy values ​​calculated in the previous one or several iterations. The peak value refers to the maximum value that the instantaneous correlation energy can reach within the search interval, and this point corresponds to the optimal alignment position of the code phase.

[0126] After calculating the instantaneous correlated energy P(τ) in each iteration, it is compared with the energy values ​​from the previous iterations. Based on the comparison results, an optimization algorithm determines the fractional delay τ' to be attempted in the next iteration in order to get closer to the energy peak. For example, gradient ascent can be used, which determines the search direction and step size by comparing the energy changes of adjacent delay points. This iterative process continues, constantly adjusting the fractional delay and calculating the energy, until a preset convergence condition is met, such as two consecutive energy value changes being less than a threshold, or the search step size being less than a certain accuracy requirement. At this point, the instantaneous correlated energy is considered to have reached its peak.

[0127] S340: The fractional delay corresponding to the instantaneous correlation energy reaching its peak is determined as the target fractional delay, and the target fractional delay is used as code phase error information.

[0128] When the iterative loop in S330 terminates, the fractional delay value used in the last iteration to peak the instantaneous correlation energy is determined as the target fractional delay. This target fractional delay, measured in sampling intervals, precisely quantifies the phase deviation of the local pseudocode relative to the input signal pseudocode. Finally, this target fractional delay value is output as high-precision code phase error information for subsequent pseudocode correction.

[0129] For example, the spread spectrum digital signal is first mixed using the phase-corrected local carrier generated in S130 to obtain a complex baseband signal. Then, to accurately estimate the code phase error, an iterative optimization process is initiated. A search interval of fractional delay is set to [-0.5, +0.5] sampling intervals, and the gradient ascent method is used for optimization. In the first iteration, an initial fractional delay τ = 0 is applied to the baseband signal using an adjustable fractional delay digital filter, and the processed delayed baseband signal is correlated with the instantaneous code of the local pseudocode to calculate the corresponding instantaneous correlation energy P(0). In the second iteration, a small positive fractional delay τ = 0.1 is applied, and the instantaneous correlation energy P(0.1) is calculated. Based on the comparison result that P(0.1) is greater than P(0), the algorithm determines that the gradient direction of energy growth is positive. In subsequent iterations, the fractional delay continues to be adjusted in the positive direction with varying step sizes, and the instantaneous correlation energy is continuously calculated until the convergence condition is met. For example, when the iteration reaches a fractional delay τ = 0.236, the corresponding instantaneous correlation energy reaches its peak. At this point, further increasing or decreasing the fractional delay will cause the energy to decrease, and the iteration will terminate. Finally, this 0.236 sampling interval that causes the instantaneous correlation energy to reach its peak is determined as the target fractional delay and used as high-precision code phase error information for subsequent final correction of the local pseudocode.

[0130] In one feasible implementation, the local pseudocode is corrected using code phase error information to obtain a corrected local pseudocode. After initializing the narrow-bandwidth frequency-locked loop, phase-locked loop, and delay-locked loop using the corrected local carrier and the corrected local pseudocode, the spread spectrum modulation signal is tracked, including:

[0131] Based on the code phase error information, a phase control word for a numerically controlled oscillator is determined to generate a corrected local pseudo-code that is aligned with the code phase of the spread spectrum digital signal.

[0132] The phase control word of a numerically controlled oscillator (NCO) is a digital input value used to precisely control the phase of the NCO's output signal. By changing this control word, the generation timing of the local pseudocode can be fine-tuned.

[0133] First, the target fractional delay code phase error information obtained in S140 is converted into a specific phase adjustment amount. Then, this calculated phase adjustment amount is added to or subtracted from the phase accumulator inside the NCO currently responsible for generating the local pseudocode. This updated accumulator value is the new phase control word. The NCO continues to generate a pseudocode sequence based on this new phase control word; this sequence is the corrected local pseudocode precisely aligned with the phase of the input signal code.

[0134] The frequency parameters of the corrected local carrier are set as the initial state parameters of the narrow-bandwidth frequency-locked loop, and the phase parameters of the corrected local carrier are set as the initial state parameters of the narrow-bandwidth phase-locked loop.

[0135] The initial state parameters of a frequency-locked loop (FLL) refer to the frequency values ​​preset by the FLL before starting closed-loop operation; these values ​​serve as the starting point for its tracking. The initial state parameters of a phase-locked loop (PLL) refer to the phase values ​​preset by the PLL before starting closed-loop operation; these values ​​serve as the starting point for its tracking.

[0136] The frequency parameters of the corrected local carrier finally generated in S130, such as its precise frequency value, are directly written into the frequency register of the FLL loop filter or NCO as the initial state parameters of the FLL. At the same time, the phase parameters of the corrected local carrier, such as its precise phase value, are directly written into the phase register of the PLL loop filter or NCO as the initial state parameters of the PLL.

[0137] The phase parameters of the local pseudocode correction are set as the initial state parameters of the narrow-bandwidth delay-locked loop, and the frequency-locked loop, phase-locked loop, and delay-locked loop are started to perform closed-loop tracking of the spread spectrum modulation signal.

[0138] The initial state parameters of the delay-locked loop (DLL) refer to the code phase values ​​preset before the DLL starts closed-loop operation. The current phase of the sub-generated correction local pseudocode is used as the initial state parameter of the DLL and loaded into the phase register of its loop filter or NCO. At this point, the initial state parameters of the FLL, PLL, and DLL loops have been accurately set based on high-precision open-loop estimation results. Subsequently, a start command is issued to switch these three narrow-bandwidth loops to closed-loop operation mode and begin tracking the spread spectrum modulation signal.

[0139] For example, in S140, the system determines the code phase error information to be 0.236 sampling intervals. First, this error information is converted into a specific phase adjustment value and used to update the phase control word of the NCO responsible for generating the local pseudocode. After adjustment, the NCO generates a corrected local pseudocode that is precisely aligned with the phase of the input signal code.

[0140] For example, the obtained frequency parameter of the corrected local carrier, 5.420152MHz, is set as the initial state parameter of the narrow-bandwidth FLL. The phase parameter of the corrected local carrier, 4.5 degrees, is set as the initial state parameter of the narrow-bandwidth PLL. Simultaneously, the current phase of the corrected local pseudo-code is set as the initial state parameter of the narrow-bandwidth DLL. Since the initial errors of all three loops, FLL, PLL, and DLL, have been accurately compensated before entering closed-loop mode, these preset narrow-bandwidth tracking loops are then activated. After receiving a signal, the loop can skip the lengthy error-pulling process and enter the locked state almost instantaneously, beginning high-precision and stable tracking of the satellite signal. This allows for the rapid output of high-precision pseudorange measurements, solving the technical problem of rapid reacquisition after frequent signal interruptions in complex environments.

[0141] Based on the same concept, embodiments of this application provide a fast and accurate tracking system for spread spectrum signals, which will be described below in conjunction with... Figure 4 The fast and accurate tracking system for spread spectrum signals provided in the embodiments of this application will be described in detail.

[0142] Figure 4 This is a structural block diagram of a fast and accurate tracking system for spread spectrum signals, as shown in an embodiment of this application.

[0143] like Figure 4 As shown, the fast and accurate tracking system for this spread spectrum signal may include:

[0144] The acquisition module 410 is used to acquire the spread spectrum modulation signal and oversample the spread spectrum modulation signal at a preset sampling rate to generate a spread spectrum digital signal including multiple sampling points in each chip period.

[0145] The calculation module 420 is used to mix the spread spectrum digital signal using the local carrier and to despread and perform coherent integration calculation on the mixed spread spectrum digital signal using the local pseudocode to generate in-phase components and quadrature components.

[0146] The correction module 430 is used to calculate frequency error information and phase error information based on the in-phase and quadrature components at continuous time intervals, and to use the frequency error information and phase error information to perform frequency and phase correction on the local carrier to obtain the corrected local carrier.

[0147] The delay module 440 is used to mix the spread spectrum digital signal with the corrected local carrier to obtain the baseband signal, apply an adjustable fractional delay to the baseband signal, and determine the target fractional delay by calculating the instantaneous correlation energy under different fractional delays, thereby obtaining code phase error information.

[0148] The tracking module 450 is used to correct the local pseudocode using code phase error information to obtain the corrected local pseudocode. After initializing the narrow-bandwidth frequency-locked loop, phase-locked loop and delay-locked loop using the corrected local carrier and the corrected local pseudocode, it tracks the spread spectrum modulation signal.

[0149] In one embodiment, the acquisition module 410 is specifically used to synchronously acquire two orthogonal polarization components of the spread spectrum modulation signal, and oversample the two orthogonal polarization components at a preset sampling rate to generate a first spread spectrum digital signal and a second spread spectrum digital signal including multiple sampling points in each chip period; before mixing the spread spectrum digital signal with the local carrier, Stokes parameters are calculated based on the first spread spectrum digital signal and the second spread spectrum digital signal; according to the Stokes parameters, polarization synthesis processing is performed on the first spread spectrum digital signal and the second spread spectrum digital signal to generate a target spread spectrum digital signal; in the mixing of the spread spectrum digital signal with the local carrier, the spread spectrum digital signal is the target spread spectrum digital signal.

[0150] In one embodiment, the acquisition module 410 is specifically used to extract azimuth angle information and elliptic angle information representing the polarization state of the received signal from the Stokes parameters, and generate a complex polarization correction operator based on the azimuth angle information and elliptic angle information according to the preset reference polarization state; take the first spread spectrum digital signal as the first input and the second spread spectrum digital signal as the second input, and combine them together to form a dual-channel complex signal; perform matrix multiplication operation between the dual-channel complex signal and the polarization correction operator to obtain the corrected complex signal, and merge the two channels of the complex signal to generate the target spread spectrum digital signal.

[0151] In one embodiment, the local carrier includes an in-phase local carrier signal and a quadrature local carrier signal; the calculation module 420 is specifically used to multiply the spread spectrum digital signal and the in-phase local carrier signal point by point to obtain a first mixed signal, and simultaneously multiply the spread spectrum digital signal and the quadrature local carrier signal point by point to obtain a second mixed signal; multiply the first mixed signal and the local pseudocode point by point to obtain a first despread signal, and simultaneously multiply the second mixed signal and the local pseudocode point by point to obtain a second despread signal; within a preset coherent integration time, all sample values ​​of the first despread signal are summed to obtain the in-phase component, and all sample values ​​of the second despread signal are summed to obtain the quadrature component.

[0152] In one embodiment, the correction module 430 is specifically used to generate frequency error information by calculating multiple instantaneous frequency deviation values ​​and performing an arithmetic average within a preset statistical period, wherein each instantaneous frequency deviation value is obtained by performing cross-multiplication, dot product, and arctangent operation on a set of in-phase and quadrature components obtained from consecutive moments within the preset statistical period; the frequency error information is used to correct the frequency of the local carrier; phase error information is generated by calculating multiple instantaneous phase deviation values ​​and performing an arithmetic average within the next preset statistical period, wherein each instantaneous phase deviation value is obtained by performing an arctangent operation on a set of in-phase and quadrature components obtained from consecutive moments within the next preset statistical period; the phase of the frequency-corrected local carrier is corrected using the phase error information to obtain a corrected local carrier.

[0153] In one embodiment, the delay module 440 is specifically configured to perform mixing processing on the spread spectrum digital signal using a corrected local carrier to generate a complex baseband signal; set a search interval for a fractional delay, and iteratively perform the following operations using an adjustable fractional delay digital filter: apply a fractional delay selected within the search interval to the baseband signal to generate a delayed baseband signal, and perform correlation integration operation between the delayed baseband signal and the instantaneous code of the local pseudocode to generate instantaneous correlation energy corresponding to the selected fractional delay; adjust the fractional delay selected within the search interval in the next iteration according to the instantaneous correlation energy until the instantaneous correlation energy reaches a peak value; determine the fractional delay corresponding to the instantaneous correlation energy reaching the peak value as the target fractional delay, and use the target fractional delay as code phase error information.

[0154] In one embodiment, the tracking module 450 is specifically configured to determine a phase control word for a numerically controlled oscillator used to generate a local pseudo-code based on the code phase error information, so as to generate a corrected local pseudo-code aligned with the code phase of the spread spectrum digital signal; set the frequency parameter of the corrected local carrier as the initial state parameter of a narrow-bandwidth frequency-locked loop, and set the phase parameter of the corrected local carrier as the initial state parameter of a narrow-bandwidth phase-locked loop; set the phase parameter of the corrected local pseudo-code as the initial state parameter of a narrow-bandwidth delay-locked loop, and start the frequency-locked loop, phase-locked loop, and delay-locked loop to perform closed-loop tracking of the spread spectrum modulation signal.

[0155] Figure 4 Each module in the system shown has an implementation Figures 1 to 3 The functions of each step in the process and their corresponding technical effects are described in detail here for the sake of brevity.

[0156] Figure 5 A schematic diagram of the hardware structure of an electronic device provided in one embodiment of this application is shown.

[0157] The electronic device may include a processor 510 and a memory 520 storing computer program instructions.

[0158] Specifically, the processor 510 may include a central processing unit (CPU), an application-specific integrated circuit (ASIC), or one or more integrated circuits that can be configured to implement the embodiments of this application.

[0159] Memory 520 may include mass storage for data or instructions. For example, and not limitingly, memory 520 may include a hard disk drive (HDD), floppy disk drive, flash memory, optical disk, magneto-optical disk, magnetic tape, or Universal Serial Bus (USB) drive, or a combination of two or more of these. Where appropriate, memory 520 may include removable or non-removable (or fixed) media. Where appropriate, memory 520 may be internal or external to the integrated gateway disaster recovery device. In a particular embodiment, memory 520 is non-volatile solid-state memory.

[0160] Memory may include read-only memory (ROM), random access memory (RAM), disk storage media devices, optical storage media devices, flash memory devices, and electrical, optical, or other physical / tangible memory storage devices. Therefore, typically, memory includes one or more tangible (non-transitory) computer-readable storage media (e.g., memory devices) encoded with software including computer-executable instructions, and when the software is executed (e.g., by one or more processors), it is operable to perform the operations described with reference to the method according to the first aspect of this disclosure.

[0161] The processor 510 reads and executes computer program instructions stored in the memory 520 to implement any of the spread spectrum signal fast and accurate tracking methods in the above embodiments.

[0162] In one example, the electronic device may also include a communication interface 530 and a bus 540. Wherein, such as Figure 5 As shown, the processor 510, memory 520, and communication interface 530 are connected through bus 540 and complete communication with each other.

[0163] The communication interface 530 is mainly used to realize communication between various modules, devices, units and / or equipment in the embodiments of this application.

[0164] Bus 540 includes hardware, software, or both, that couples components of an online data traffic metering device together. For example, and not limitingly, the bus may include an Accelerated Graphics Port (AGP) or other graphics bus, an Enhanced Industry Standard Architecture (EISA) bus, a Front Side Bus (FSB), HyperTransport (HT) interconnect, an Industry Standard Architecture (ISA) bus, an Infinite Bandwidth Interconnect, a Low Pin Count (LPC) bus, a memory bus, a Microchannel Architecture (MCA) bus, a Peripheral Component Interconnect (PCI) bus, a PCI-Express (PCI-X) bus, a Serial Advanced Technology Attachment (SATA) bus, a Video Electronics Standards Association Local (VLB) bus, or other suitable buses, or combinations of two or more of these. Where appropriate, bus 540 may include one or more buses. Although specific buses are described and illustrated in embodiments of this application, this application contemplates any suitable bus or interconnect.

[0165] This electronic device can execute the fast and accurate tracking method for spread spectrum signals in the embodiments of this application, thereby achieving a combination of Figures 1 to 3 The method described is a fast and accurate tracking method for spread spectrum signals.

[0166] Furthermore, in conjunction with the fast and accurate tracking method for spread spectrum signals in the above embodiments, this application embodiment can provide a computer-readable storage medium for implementation. This computer-readable storage medium stores computer program instructions; when executed by a processor, these computer program instructions implement any of the fast and accurate tracking methods for spread spectrum signals in the above embodiments.

[0167] It should be clarified that this application is not limited to the specific configurations and processes described above and shown in the figures. For the sake of brevity, detailed descriptions of known methods are omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of this application is not limited to the specific steps described and shown. Those skilled in the art can make various changes, modifications, and additions, or change the order of steps, after understanding the spirit of this application.

[0168] The functional blocks shown in the above-described structural diagram can be implemented as hardware, software, firmware, or a combination thereof. When implemented in hardware, they can be, for example, electronic circuits, application-specific integrated circuits (ASICs), appropriate firmware, plug-ins, function cards, etc. When implemented in software, the elements of this application are programs or code segments used to perform the required tasks. Programs or code segments can be stored on a machine-readable medium or transmitted over a transmission medium or communication link via data signals carried on a carrier wave. "Machine-readable medium" can include any medium capable of storing or transmitting information. Examples of machine-readable media include electronic circuits, semiconductor memory devices, ROM, flash memory, erasable ROM (EROM), floppy disks, CD-ROMs, optical disks, hard disks, fiber optic media, radio frequency (RF) links, etc. Code segments can be downloaded via computer networks such as the Internet, intranets, etc.

[0169] It should also be noted that the exemplary embodiments mentioned in this application describe methods or systems based on a series of steps or apparatus. However, this application is not limited to the order of the above steps; that is, the steps can be performed in the order mentioned in the embodiments, or in a different order, or several steps can be performed simultaneously.

[0170] The aspects of this application have been described above with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It should be understood that each block in the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus to produce a machine such that these instructions, executable via the processor of the computer or other programmable data processing apparatus, enable the implementation of the functions / actions specified in one or more blocks of the flowchart illustrations and / or block diagrams. Such a processor can be, but is not limited to, a general-purpose processor, a special-purpose processor, a special application processor, or a field-programmable logic circuit. It is also understood that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can also be implemented by dedicated hardware performing the specified functions or actions, or can be implemented by a combination of dedicated hardware and computer instructions.

[0171] The above description is merely a specific implementation of this application. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, modules, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here. It should be understood that the protection scope of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the protection scope of this application.

Claims

1. A method of fast and accurate tracking of a spread spectrum signal, characterized by The method comprises: acquiring a spread spectrum modulated signal and oversampling the spread spectrum modulated signal at a preset sampling rate to generate a spread spectrum digital signal comprising a plurality of sampling points in each chip period; mixing the spread spectrum digital signal with a local carrier and despreading and coherent integration calculating the spread spectrum digital signal after mixing to generate in-phase and quadrature components; based on the in-phase and quadrature components at consecutive time instants, calculating frequency error information and phase error information, and correcting the frequency and phase of the local carrier using the frequency error information and the phase error information to obtain a corrected local carrier; mixing the spread spectrum digital signal with the corrected local carrier to obtain a baseband signal, applying an adjustable fractional delay to the baseband signal, and determining a target fractional delay by calculating the instantaneous correlation energy under different fractional delays to obtain code phase error information; correcting the local pseudo code using the code phase error information to obtain a corrected local pseudo code, and initializing a narrow bandwidth frequency locked loop, phase locked loop and delay locked loop using the corrected local carrier and the corrected local pseudo code, and then tracking the spread spectrum modulated signal; The method comprises: calculating a plurality of instantaneous frequency deviation values in a preset statistical period and performing arithmetic averaging to generate the frequency error information, wherein each instantaneous frequency deviation value is obtained by cross-multiplying, dot product operation and arctangent operation on a group of in-phase and quadrature components acquired at consecutive time instants in the preset statistical period; correcting the frequency of the local carrier using the frequency error information; calculating a plurality of instantaneous phase deviation values in the next preset statistical period and performing arithmetic averaging to generate the phase error information, wherein each instantaneous phase deviation value is obtained by arctangent operation on a group of in-phase and quadrature components acquired at consecutive time instants in the next preset statistical period; correcting the phase of the local carrier after frequency correction using the phase error information to obtain the corrected local carrier.

2. The method of claim 1, wherein, The method comprises: synchronously acquiring two orthogonal polarization components of the spread spectrum modulated signal and oversampling the two orthogonal polarization components at a preset sampling rate to generate a first spread spectrum digital signal and a second spread spectrum digital signal comprising a plurality of sampling points in each chip period; Before the mixing of the spread spectrum digital signal with the local carrier, the method further comprises: calculating Stokes parameters based on the first spread spectrum digital signal and the second spread spectrum digital signal; According to the Stokes parameter, the first spread spectrum digital signal and the second spread spectrum digital signal are subjected to polarization synthesis processing to generate a target spread spectrum digital signal; In the mixing of the spread spectrum digital signal with the local carrier, the spread spectrum digital signal is the target spread spectrum digital signal.

3. The method of claim 2, wherein, The Stokes parameter, the first spread spectrum digital signal and the second spread spectrum digital signal are subjected to polarization synthesis processing to generate a target spread spectrum digital signal, including: The azimuth angle information and the ellipticity angle information representing the polarization state of the received signal are extracted from the Stokes parameter, and a complex polarization correction operator is generated based on the azimuth angle information and the ellipticity angle information according to a preset reference polarization state; The first spread spectrum digital signal is input as a first channel, and the second spread spectrum digital signal is input as a second channel to form a dual-channel complex signal; The dual-channel complex signal is subjected to matrix multiplication operation with the polarization correction operator to obtain a corrected complex signal, and the two channels of the complex signal are combined to generate the target spread spectrum digital signal.

4. The method of claim 1, wherein, The local carrier includes an in-phase local carrier signal and a quadrature local carrier signal; the mixing of the spread spectrum digital signal with the local carrier, and the despreading and coherent integration calculation of the mixed spread spectrum digital signal with the local pseudo code to generate in-phase components and quadrature components, include: The spread spectrum digital signal is multiplied point by point with the in-phase local carrier signal to obtain a first mixed signal, and the spread spectrum digital signal is multiplied point by point with the quadrature local carrier signal to obtain a second mixed signal; The first mixed signal is multiplied point by point with the local pseudo code to obtain a first despreading signal, and the second mixed signal is multiplied point by point with the local pseudo code to obtain a second despreading signal; All sample values of the first despreading signal are accumulated and summed within a preset coherent integration time to obtain the in-phase components, and all sample values of the second despreading signal are accumulated and summed to obtain the quadrature components.

5. The method of claim 1, wherein, The mixing of the spread spectrum digital signal with the corrected local carrier to obtain a baseband signal, the application of an adjustable fractional delay to the baseband signal, and the determination of a target fractional delay by calculating the instantaneous correlation energy under different fractional delays to obtain code phase error information, include: The spread spectrum digital signal is subjected to mixing processing with the corrected local carrier to generate a complex baseband signal; A search interval of the fractional delay is set, and an adjustable fractional delay digital filter is used to iteratively perform the following operations: a selected fractional delay within the search interval is applied to the baseband signal to generate a delayed baseband signal, and the delayed baseband signal is subjected to correlation integration operation with the local pseudo code to generate the instantaneous correlation energy corresponding to the selected fractional delay. According to the instantaneous correlation energy, the fractional delay selected in the search range in the next iteration is adjusted until the instantaneous correlation energy reaches a peak value; The fractional delay corresponding to the peak value of the instantaneous correlation energy is determined as the target fractional delay, and the target fractional delay is taken as the code phase error information.

6. The method of claim 1, wherein, The code phase error information is used to correct the local pseudo-code to obtain a corrected local pseudo-code, and after the corrected local carrier and the corrected local pseudo-code are used to initialize a narrow-band frequency-locked loop, a phase-locked loop and a delay-locked loop, the spread spectrum modulated signal is tracked, including: According to the code phase error information, a phase control word of a numerically controlled oscillator used to generate the local pseudo-code is determined to generate the corrected local pseudo-code aligned with the code phase of the spread spectrum digital signal; The frequency parameter of the corrected local carrier is set as the initial state parameter of the narrow-band frequency-locked loop, and the phase parameter of the corrected local carrier is set as the initial state parameter of the narrow-band phase-locked loop; The phase parameter of the corrected local pseudo-code is set as the initial state parameter of the narrow-band delay-locked loop, and the frequency-locked loop, the phase-locked loop and the delay-locked loop are started to perform closed-loop tracking on the spread spectrum modulated signal.

7. A fast and accurate tracking system for spread spectrum signals, characterized in that, The system comprises: An acquisition module is configured to acquire a spread spectrum modulated signal and oversample the spread spectrum modulated signal at a preset sampling rate to generate a spread spectrum digital signal comprising a plurality of sampling points in each chip period; A calculation module is configured to mix the spread spectrum digital signal with a local carrier, despread and coherent integrate the mixed spread spectrum digital signal with a local pseudo-code to generate in-phase and quadrature components; A correction module is configured to calculate frequency error information and phase error information based on the in-phase and quadrature components at consecutive time instants, and correct the frequency and phase of the local carrier using the frequency error information and the phase error information to obtain a corrected local carrier. The correction module is specifically configured to generate the frequency error information by calculating a plurality of instantaneous frequency deviation values in a preset statistical period and performing arithmetic averaging, wherein each instantaneous frequency deviation value is obtained by cross-multiplying, dot product operation and arctangent operation on a group of in-phase and quadrature components acquired at consecutive time instants in the preset statistical period; correct the frequency of the local carrier using the frequency error information; generate the phase error information by calculating a plurality of instantaneous phase deviation values in the next preset statistical period and performing arithmetic averaging, wherein each instantaneous phase deviation value is obtained by arctangent operation on a group of in-phase and quadrature components acquired at consecutive time instants in the next preset statistical period; The phase of the local carrier after frequency correction is corrected using the phase error information to obtain the corrected local carrier; a delay module, configured to mix the spread spectrum digital signal with the corrected local carrier to obtain a baseband signal, apply an adjustable fractional delay to the baseband signal, and determine a target fractional delay by calculating instantaneous correlation energies under different fractional delays to obtain code phase error information; a tracking module, configured to correct the local pseudo code using the code phase error information to obtain a corrected local pseudo code, and initialize a narrow bandwidth frequency locked loop, phase locked loop and delay locked loop using the corrected local carrier and the corrected local pseudo code, and then track the spread spectrum modulated signal.

8. An electronic device, comprising: The device comprises a processor and a memory storing computer program instructions; The processor executes the computer program instructions to implement the fast and accurate tracking method of the spread spectrum signal according to any one of claims 1-6.

9. A computer-readable storage medium, characterized in that, The computer readable storage medium stores computer program instructions, and the computer program instructions are executed by the processor to implement the fast and accurate tracking method of the spread spectrum signal according to any one of claims 1-6.

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