Anti-interference acquisition method of satellite direct sequence spread spectrum signal under high dynamic Doppler channel

Abstract

The invention discloses an anti-interference acquisition method for a satellite direct sequence spread spectrum signal under a high dynamic Doppler channel. The method comprises the following steps: S1, performing down-conversion processing on a received intermediate frequency signal; s2, performing segmented parallel multiple correlation operation according to the AC spread spectrum sequence and the down-conversion signal; s3, comparing the maximum module value of the FFT operation result with a preset judgment threshold, and executing the step S4 or returning to the step S2 according to the relationship between the maximum module value and the preset judgment threshold; s4, obtaining a residual frequency offset estimation value according to the captured frequency offset coarse estimation values corresponding to each frame of signal to be compensated and the previous frame of signal to be compensated and the AC spread spectrum sequence; and S5, performing frequency offset compensation on each frame of to-be-compensated signal according to the coarse frequency offset estimation value and the residual frequency offset estimation value to obtain a compensated signal. According to the method, the frequency offset of the signal can be accurately compensated before de-spreading, so that correct de-spreading is completed, the spread spectrum gain is released, and finally the de-spread signal is subjected to phase locking.

Description

Technical Field

[0001] The present invention belongs to the technical field of signal processing in wireless communication systems, and particularly relates to an anti-interference acquisition method for satellite direct-sequence spread-spectrum signals in a high-dynamic Doppler channel. Background Art

[0002] In the satellite communication scenario, due to the satellite rotating around the earth at a very high speed, significant Doppler frequency offsets will occur in the satellite-ground link and the inter-satellite link. The magnitude of the Doppler frequency offset depends on the relative speed between the satellite and the ground station. The high-speed movement of low-earth orbit satellites results in a large frequency offset range. In a high-dynamic environment, the Doppler frequency offset changes rapidly, which poses challenges to satellite communication. Especially in a low signal-to-noise ratio environment, it is difficult to accurately estimate the frequency offset, affecting signal acquisition, despreading, and demodulation. To address these challenges, the communication system needs to have stronger frequency offset estimation and compensation capabilities to ensure a reliable communication link in a high-dynamic environment.

[0003] Spread-spectrum technology has been widely used in satellite-ground link communication, especially for improving anti-interference ability and enhancing information concealment. Spread-spectrum communication transmits narrowband signals by expanding them into a wider frequency spectrum range, making it more difficult to detect and identify the received signals in noise and interference. This technology can significantly improve the anti-interference performance of communication, especially in a low signal-to-noise ratio environment. In satellite-ground link communication, the high-speed movement of the satellite relative to the ground will cause Doppler frequency offset, which will introduce certain challenges. Especially in the reception and demodulation of spread-spectrum communication signals, the frequency offset will prevent the receiver from accurately despreading, affecting the acquisition and demodulation accuracy of the signal.

[0004] The frequency offset acquisition technology combining the partial match filter (PMF) and the fast Fourier transform (FFT) is often used to estimate the frequency offset in the satellite-ground link. However, traditional methods face some limitations in dealing with large frequency offsets. Especially in a low signal-to-noise ratio environment, the remaining frequency offset is still large, which will still cause the signal to be unable to be correctly despread. In an environment with a large Doppler frequency offset and a low signal-to-noise ratio, a more accurate frequency offset estimation method needs to be adopted to improve the frequency offset compensation accuracy to ensure the reliability of signal despreading and subsequent processing. Summary of the Invention

[0005] In order to solve the above problems existing in the prior art, the present invention provides an anti-interference acquisition method for satellite direct-sequence spread-spectrum signals in a high-dynamic Doppler channel.

[0006] The technical problems to be solved by the present invention are realized through the following technical solutions:

[0007] In a first aspect, the present invention provides an anti-interference acquisition method for satellite direct-sequence spread-spectrum signals in a high-dynamic Doppler channel, and the method includes:

[0008] S1. Down-convert the received intermediate frequency signal to obtain a down-converted signal;

[0009] S2. Perform segmented parallel complex correlation operations on the AC spreading sequence stored locally in the receiver and the down-converted signal to obtain a complex correlation operation result;

[0010] S3. Perform an FFT operation on the complex correlation operation result, compare the maximum modulus value of the FFT operation result with a preset decision threshold. When the maximum modulus value is greater than or equal to the preset decision threshold, capture the signal to be compensated in the current frame of the down-converted signal, calculate a coarse frequency offset estimate value according to the start position index of the signal to be compensated in the current frame, and execute step S4; when the maximum modulus value is less than the preset decision threshold, cyclically shift the down-converted signal to the right and return to step S2;

[0011] S4. Obtain a residual frequency offset estimate value according to the coarse frequency offset estimate values corresponding to the signal to be compensated in each captured frame and the signal to be compensated in the previous frame, and the AC spreading sequence;

[0012] S5. Perform frequency offset compensation on the signal to be compensated in each frame according to the coarse frequency offset estimate value and the residual frequency offset estimate value to obtain a compensated signal.

[0013] Optionally, S2 includes:

[0014] Spread the AC sequence by a Gold sequence to obtain the AC spreading sequence;

[0015] Perform segmented parallel complex correlation operations on the AC spreading sequence and the down-converted signal to obtain a complex correlation operation result.

[0016] Optionally, when the index corresponding to the maximum modulus value of the FFT operation result is greater than or equal to half of the FFT operation points, the coarse frequency offset estimate value is expressed as follows:

[0017] f d '=(index - N - 1) / (N×K×T s );

[0018] Wherein, f d ' represents the coarse frequency offset estimate value, index represents the index corresponding to the maximum modulus value of the FFT operation result of the signal to be compensated in the current frame, N is the number of FFT operation points, K is the length of the matched filter, T s Sampling period.

[0019] Optionally, when the index corresponding to the maximum modulus value of the FFT operation result is less than half of the FFT operation points, the coarse frequency offset estimate value is expressed as follows:

[0020] f d ' = (index - 1) / (N × K × T s )。

[0021] Optionally, S4 includes:

[0022] Subtracting the coarse frequency offset estimation values respectively corresponding to each frame of signal to be compensated and the previous frame of signal to be compensated to obtain an estimation value difference;

[0023] Preprocessing each frame of signal to be compensated according to the estimation value difference and the coarse frequency offset estimation value to obtain a preprocessed signal;

[0024] Performing a residual frequency offset estimation search on the preprocessed signal by using the AC spreading sequence to obtain the residual frequency offset estimation value.

[0025] Optionally, S5 includes:

[0026] Adding the coarse frequency offset estimation value and the residual frequency offset estimation value to obtain a total Doppler frequency offset estimation value;

[0027] Performing frequency offset compensation on each frame of signal to be compensated according to the total Doppler frequency offset estimation value to obtain a compensated signal.

[0028] Optionally, the method further includes:

[0029] Despreading the compensated signal to release the spreading gain to obtain a despread signal;

[0030] Performing phase locking on the despread signal through a phase-locked loop to eliminate the frequency offset and obtain an output signal with the frequency offset eliminated.

[0031] In a second aspect, the present invention provides an anti-jamming acquisition device for satellite direct spread signals in a high-dynamic Doppler channel. The device includes:

[0032] A down-conversion module for performing down-conversion processing on the received intermediate-frequency signal to obtain a down-converted signal;

[0033] A parallel operation module for performing segmented parallel complex correlation operations according to the AC spreading sequence stored locally in the receiver and the down-converted signal to obtain a complex correlation operation result;

[0034] A capture module is used to perform FFT operation on the complex correlation operation result, compare the maximum modulus value of the FFT operation result with a preset decision threshold. When the maximum modulus value is greater than or equal to the preset decision threshold, the current frame of the signal to be compensated in the down-converted signal is captured, the coarse frequency offset estimation value is calculated according to the starting position index of the current frame of the signal to be compensated, and the estimation value calculation module is executed; when the maximum modulus value is less than the preset decision threshold, the down-converted signal is cyclically shifted to the right and then returned to the parallel operation module;

[0035] An estimation value calculation module is used to obtain the remaining frequency offset estimation value according to the coarse frequency offset estimation values corresponding to each captured frame of the signal to be compensated and the previous frame of the signal to be compensated, and the AC spreading sequence;

[0036] A signal compensation module is used to perform frequency offset compensation on each frame of the signal to be compensated according to the coarse frequency offset estimation value and the remaining frequency offset estimation value to obtain the compensated signal.

[0037] The technical solution provided by the embodiment of the present invention may include the following beneficial effects:

[0038] In the above technical solution, the present invention estimates the frequency offset of each frame of the signal to be compensated in an accurate estimation manner according to the AC spreading sequence, and then searches for the remaining frequency offset estimation value by using the strong autocorrelation of the AC spreading sequence for the preprocessed signal according to the change rate of the frequency offset estimation values between each frame of the signal to be compensated. Based on the coarse frequency offset estimation value and the remaining frequency offset estimation value, actual frequency offset compensation is performed to ensure correct despreading of the signal under low signal-to-noise ratio. Finally, the phase-locked loop is used to perform phase locking on the despread signal, and the phase-locked signal is output after compensating the frequency offset. The present invention can accurately compensate the frequency offset of the signal before despreading under low signal-to-noise ratio conditions and release the spreading gain.

[0039] The following will further describe the present invention in detail with reference to the drawings and embodiments. Description of the Drawings

[0040] Figure 1 is a flowchart of an anti-jamming capture method for satellite direct spread signals in a high-dynamic Doppler channel provided by an embodiment of the present invention;

[0041] Figure 2 is a specific implementation flowchart of an anti-jamming capture method for satellite direct spread signals in a high-dynamic Doppler channel provided by an embodiment of the present invention;

[0042] Figure 3 is a schematic diagram of signal capture provided by an embodiment of the present invention;

[0043] Figure 4It is a schematic diagram of the residual frequency offset of input and output signals provided by an embodiment of the present invention;

[0044] Figure 5 It is a schematic diagram of error comparison provided by an embodiment of the present invention;

[0045] Figure 6 It is a block diagram of an anti-jamming acquisition device for satellite direct-sequence spread spectrum signals in a high-dynamic Doppler channel provided by an embodiment of the present invention. Specific embodiments

[0046] The following further describes the present invention in detail with reference to specific embodiments, but the implementation manners of the present invention are not limited thereto.

[0047] Figure 1 It is a flowchart of an anti-jamming acquisition method for satellite direct-sequence spread spectrum signals in a high-dynamic Doppler channel provided by an embodiment of the present invention. As Figure 1 shown, the method may include:

[0048] S1. Perform down-conversion processing on the received intermediate-frequency signal to obtain a down-converted signal.

[0049] It can be understood that before S1, the data at the sending end is continuous. Each frame of signal consists of three parts: a synchronization header, data, and a guard interval. The total length of each frame of signal is H. Among them, the synchronization header, valid data, and guard interval use different Gold spreading sequences to spread the data to form a direct-sequence spread spectrum signal. The frequency offset of each bit codeword of the signal changes continuously. Among them, the frequency offset of the first codeword in the first frame to the Xth frame is f1, f2, f3, …, f X , then the frequency offset of the mth codeword in the nth frame is expressed as: f n +(m - 1)×(f n+1 -f n ) / H. Before S1, root-raised cosine filtering is applied to the signal through matched filtering for pulse shaping, which helps to reduce inter-symbol interference. Then, the down-sampling of the filtered signal is performed to reduce the sampling rate of the signal for subsequent processing. And it is necessary to correctly capture the starting position index of each frame of signal in the coarse frequency offset estimation stage to ensure the correctness of subsequent signal processing.

[0050] S2. Perform segmented parallel complex correlation operations on the AC spreading sequence stored locally in the receiver and the down-converted signal to obtain the result of the complex correlation operation.

[0051] Optionally, Figure 2 It is a specific implementation flowchart of an anti-jamming acquisition method for satellite direct-sequence spread spectrum signals in a high-dynamic Doppler channel provided by an embodiment of the present invention. As Figure 2 shown, S2 includes:

[0052] The AC sequence is spread-spectrum by a Gold sequence to obtain an AC spread-spectrum sequence;

[0053] According to the AC spread-spectrum sequence and the down-converted signal, a segmented parallel complex correlation operation is performed to obtain a complex correlation operation result.

[0054] It can be understood that the AC spread-spectrum sequence is obtained by directly spreading the AC sequence composed of "0" and "1" using a Gold sequence with good autocorrelation. The stored L spread-spectrum data are grouped into M groups, where M represents the number of parallel partial match filters in the complex correlation operation, and each group has K data, where K represents the length of each partial match filter, and L = M × K. According to the grouped spread-spectrum data, a parallel complex correlation operation is performed on the down-converted signal in segments.

[0055] S3. Perform an FFT operation on the complex correlation operation result, compare the maximum modulus value of the FFT operation result with a preset decision threshold. When the maximum modulus value is greater than or equal to the preset decision threshold, the signal to be compensated in the current frame of the down-converted signal is captured, and a coarse frequency offset estimate value is calculated according to the starting position index of the signal to be compensated in the current frame, and step S4 is executed; when the maximum modulus value is less than the preset decision threshold, the down-converted signal is circularly shifted to the right and then returned to step S2.

[0056] It can be understood that if the maximum modulus value of the FFT operation result is greater than the decision threshold, the signal to be compensated in the current frame of the down-converted signal is captured, and a coarse frequency offset estimate value is calculated according to the starting position index.

[0057] Optionally, when the index corresponding to the maximum modulus value of the FFT operation result is greater than or equal to half of the number of FFT operation points, the coarse frequency offset estimate value is expressed as follows:

[0058] f d '=(index - N - 1) / (N × K × T s );

[0059] where, f d ' represents the coarse frequency offset estimate value, index represents the index corresponding to the maximum modulus value of the FFT operation result, N is the number of FFT operation points, K is the length of the match filter, and T s is the sampling period.

[0060] Optionally, when the index corresponding to the maximum modulus value of the FFT operation result is less than half of the number of FFT operation points, the coarse frequency offset estimate value is expressed as follows:

[0061] f d '=(index - 1) / (N × K × T s );

[0062] It can be understood that if the index is greater than N / 2, the rough frequency offset estimate value is negative; if the index is less than or equal to N / 2, the rough frequency offset estimate value is positive.

[0063] S4. Obtain the remaining frequency offset estimate value according to the rough frequency offset estimate values corresponding to each frame of the signal to be compensated and the previous frame of the signal to be compensated, respectively, and the AC spread spectrum sequence.

[0064] Optionally, referring to Figure 2 , S4 includes:

[0065] Subtract the rough frequency offset estimate values corresponding to each frame of the signal to be compensated and the previous frame of the signal to be compensated, respectively, to obtain an estimate value difference;

[0066] Preprocess each frame of the signal to be compensated according to the estimate value difference and the rough frequency offset estimate value to obtain a preprocessed signal;

[0067] Use the AC spread spectrum sequence to perform a remaining frequency offset estimation search on the preprocessed signal to obtain the remaining frequency offset estimate value.

[0068] It can be understood that the strong autocorrelation of the AC spread spectrum sequence is used to perform a remaining frequency offset search estimation on the preprocessed signal to obtain the remaining frequency offset estimate value f d ”. Traverse all possible frequency offset values fsearch, correlate the sequence of the signal synchronization header part with the local pseudo-code. If the correlation value is the largest when the frequency offset is f s ' earch , then f d ” = f s ' earch is the best estimate value of the remaining frequency offset of the current frame.

[0069] S5. Perform frequency offset compensation on each frame of the signal to be compensated according to the rough frequency offset estimate value and the remaining frequency offset estimate value to obtain a compensated signal.

[0070] Optionally, referring to Figure 2 , S5 includes:

[0071] Add the rough frequency offset estimate value and the remaining frequency offset estimate value to obtain the total Doppler frequency offset estimate value;

[0072] Perform frequency offset compensation on each frame of the signal to be compensated according to the total Doppler frequency offset estimate value to obtain a compensated signal.

[0073] Optionally, the method may further include:

[0074] Perform despreading on the compensated signal to release the spreading gain to obtain a despread signal;

[0075] Perform phase locking on the despread signal through a phase-locked loop to eliminate the frequency offset and obtain an output signal with the frequency offset eliminated.

[0076] In one embodiment, Figure 3 is a schematic diagram of signal acquisition provided by an embodiment of the present invention, Figure 4 is a schematic diagram of the residual frequency offset of the input and output signals provided by an embodiment of the present invention. Combining Figure 3 and Figure 4 , the signal-to-noise ratio is set to -24 dB, Figure 3 represents the signal acquisition-related results of coarse frequency offset estimation, Figure 4 represents the residual frequency offset of the input and output signals of the present invention, where the input signal refers to the down-converted signal and the output signal refers to the output signal after frequency offset cancellation. Figure 5 is a schematic diagram of error comparison provided by an embodiment of the present invention. Combining Figure 5 , Figure 5 The results shown in represent the residual frequency offset before despreading, that is, the residual frequency offset of the signal compensated according to the coarse frequency offset estimation and the residual frequency offset estimation results. The signal-to-noise ratio is set in the range of -25 dB to 0 dB, the Doppler frequency offset range is set between -300 KHz and 300 KHz, the Doppler change rate is 30 - 40 KHz / s, 8 frames of signals are transmitted per second, and the sampling rate F s = 4.096e6; when the length K of the partial match filter is 8, the number of parallel partial match filters in the partial complex correlation operation is 1024. The Doppler frequency offset estimation resolution Δf of the coarse frequency offset estimation d = 1 / (NKT s ) = 500 Hz, that is, the remaining frequency offset estimation range after the compensation in the coarse frequency offset estimation step is within ±500 Hz, which is convenient for the next remaining frequency offset estimation search. After compensation according to the above frequency offset estimation results, correct despreading of the signal can be achieved at low signal-to-noise ratio, and the frequency offset is eliminated by phase locking through a phase-locked loop, thus ensuring the subsequent synchronization tracking work.

[0077] In the above technical solution, the present invention estimates the frequency offset of each frame of the signal to be compensated in an accurate estimation manner according to the AC spreading sequence, and then, according to the change rate of the frequency offset estimation values between each frame of the signal to be compensated, uses the strong autocorrelation of the AC spreading sequence to search for the remaining frequency offset of the preprocessed signal to obtain the remaining frequency offset estimation value. Based on the coarse frequency offset estimation value and the remaining frequency offset estimation value, actual frequency offset compensation is performed to ensure correct despreading of the signal at low signal-to-noise ratio. Finally, the despread signal is phase-locked through a phase-locked loop, and the phase-locked signal is output after compensating the frequency offset. The present invention can accurately compensate the frequency offset of the signal before despreading at low signal-to-noise ratio and release the spreading gain.

[0078] Figure 6 is a block diagram of an anti-jamming acquisition device for satellite direct spread signals in a high-dynamic Doppler channel provided by an embodiment of the present invention, as shown in Figure 6As shown, the device 600 includes:

[0079] A down-conversion module 601 for performing down-conversion processing on the received intermediate-frequency signal to obtain a down-converted signal;

[0080] A parallel operation module 602 for performing segmented parallel complex correlation operations based on the AC spreading sequence stored locally in the receiver and the down-converted signal to obtain a complex correlation operation result;

[0081] A capture module 603 for performing FFT operations on the complex correlation operation result, comparing the maximum modulus value of the FFT operation result with a preset decision threshold. When the maximum modulus value is greater than or equal to the preset decision threshold, the signal to be compensated in the current frame of the down-converted signal is captured, and a coarse frequency offset estimate value is calculated based on the starting position index of the signal to be compensated in the current frame, and the estimate value calculation module is executed; when the maximum modulus value is less than the preset decision threshold, the down-converted signal is cyclically shifted to the right and then returned to the parallel operation module;

[0082] An estimate value calculation module 604 for obtaining a remaining frequency offset estimate value based on the coarse frequency offset estimate values corresponding to the signal to be compensated in each captured frame and the signal to be compensated in the previous frame, respectively, and the AC spreading sequence;

[0083] A signal compensation module 605 for performing frequency offset compensation on the signal to be compensated in each frame based on the coarse frequency offset estimate value and the remaining frequency offset estimate value to obtain a compensated signal.

[0084] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine the different embodiments or examples described in this specification.

[0085] Although the present invention has been described in connection with various embodiments herein, however, in the process of implementing the claimed invention, those skilled in the art can understand and achieve other variations of the disclosed embodiments by viewing the drawings and the disclosure. In the description of the present invention, the term "including" does not exclude other components or steps, the term "one" or "a" does not exclude a plurality of cases, and the meaning of "a plurality" is two or more unless otherwise specifically defined. In addition, certain measures are described in different embodiments, but this does not mean that these measures cannot be combined to produce good results.

[0086] For the apparatus embodiments, since they are basically similar to the method embodiments, the description is relatively simple. For the relevant parts, please refer to the partial description of the method embodiments.

[0087] It should be noted that the apparatus in the embodiments of the present invention is an apparatus applying the anti-interference acquisition method for satellite direct spread signals in the above high-dynamic Doppler channel. All embodiments of the above anti-interference acquisition method for satellite direct spread signals in the high-dynamic Doppler channel are applicable to this apparatus, and all can achieve the same or similar beneficial effects.

[0088] The above content is a further detailed description of the present invention in combination with specific preferred embodiments. It cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For those of ordinary skill in the technical field to which the present invention pertains, without departing from the concept of the present invention, several simple deductions or substitutions can be made, and all should be regarded as belonging to the protection scope of the present invention.

Claims

1. A method for anti-interference capture of satellite direct spread signals in a high dynamic Doppler channel, characterized in that: The method comprises: S1, down-converting the received intermediate frequency signal to obtain a down-converted signal; S2, performing segmented parallel complex correlation operations on the AC spread spectrum sequence and the down-converted signal stored locally in the receiver to obtain complex correlation operation results; S3, performing FFT operation on the complex correlation operation result, taking the maximum modulus value of the FFT operation result and comparing it with the preset decision threshold, when the maximum modulus value is greater than or equal to the preset decision threshold, capturing the current frame to-be-compensated signal in the down-converted signal, calculating the coarse frequency offset estimation value according to the starting position index of the current frame to-be-compensated signal, and executing step S4; when the maximum modulus value is less than the preset decision threshold, cyclically shifting the down-converted signal to the right and returning to step S2; S4, obtaining a residual frequency offset estimation value according to the coarse frequency offset estimation values ​​corresponding to each captured frame of the signal to be compensated and the previous frame of the signal to be compensated and the AC spread spectrum sequence; S5. Perform frequency offset compensation on each frame of the signal to be compensated according to the rough frequency offset estimation value and the residual frequency offset estimation value to obtain a compensated signal.

2. The anti-interference capture method of satellite direct spread signal under high dynamic Doppler channel according to claim 1, characterized in that S2 include: Spreading the AC sequence by using the Gold sequence to obtain the AC spread spectrum sequence; A segmented and parallel complex correlation operation is performed on the AC spread spectrum sequence and the down-converted signal to obtain a complex correlation operation result.

3. The anti-interference capture method of satellite direct spread signal under high dynamic Doppler channel according to claim 1, characterized in that: When the index corresponding to the maximum modulus value of the FFT operation result is greater than or equal to half of the number of FFT operation points, the rough frequency offset estimate is expressed as follows: f d '=(index-N-1) / (N×K×T s ); Among them, f d ' represents the coarse frequency offset estimation value, index represents the index corresponding to the maximum modulus value of the FFT operation result of the signal to be compensated in the current frame, N is the number of FFT operation points, K is the length of the matched filter, T s Sampling period.

4. The anti-interference capture method of satellite direct spread signal in high dynamic Doppler channel according to claim 3, characterized in that: When the index corresponding to the maximum modulus value of the FFT operation result is less than half of the number of FFT operation points, the rough frequency offset estimate is expressed as follows: f d '=(index-1) / (N×K×T s )。 5. The anti-interference capture method of satellite direct spread signal under high dynamic Doppler channel according to claim 1, characterized in that S4 include: Subtracting the rough frequency offset estimation values ​​corresponding to each frame of the signal to be compensated and the signal to be compensated in the previous frame, respectively, to obtain an estimation value difference; Preprocessing each frame of the signal to be compensated according to the estimated value difference and the coarse estimated value of the frequency offset to obtain a preprocessed signal; The AC spread spectrum sequence is used to perform a residual frequency offset estimation search on the preprocessed signal to obtain the residual frequency offset estimation value.

6. The anti-interference capture method of satellite direct spread signal in high dynamic Doppler channel according to claim 1, characterized in that S5 include: Adding the rough frequency offset estimate and the residual frequency offset estimate to obtain a total Doppler frequency offset estimate; Frequency offset compensation is performed on each frame of the signal to be compensated according to the total Doppler frequency offset estimation value to obtain a compensated signal.

7. The anti-interference capture method of satellite direct spread signal in high dynamic Doppler channel according to claim 1, characterized in that: The method further comprises: Despreading the compensated signal to release the spread spectrum gain and obtain a despread signal; The despread signal is phase-locked by a phase-locked loop to eliminate the frequency deviation and obtain an output signal after the frequency deviation is eliminated.

8. An anti-interference capture device for satellite direct spread signals in a high dynamic Doppler channel, characterized in that: The device comprises: A down-conversion module is used to down-convert the received intermediate frequency signal to obtain a down-converted signal; A parallel operation module, used for performing segmented parallel complex correlation operation according to the AC spread spectrum sequence stored locally in the receiver and the down-converted signal to obtain a complex correlation operation result; A capture module, used for performing FFT operation on the complex correlation operation result, taking the maximum modulus value of the FFT operation result and comparing it with the preset decision threshold, when the maximum modulus value is greater than or equal to the preset decision threshold, capturing the current frame to-be-compensated signal in the down-converted signal, calculating the coarse frequency deviation estimation value according to the starting position index of the current frame to-be-compensated signal, and executing the estimation value calculation module; when the maximum modulus value is less than the preset decision threshold, the down-converted signal is cyclically shifted to the right and returned to the parallel operation module; An estimation value calculation module, used for obtaining a residual frequency offset estimation value according to the coarse frequency offset estimation values ​​corresponding to each captured frame of the signal to be compensated and the previous frame of the signal to be compensated and the AC spread spectrum sequence; The signal compensation module is used to perform frequency offset compensation on each frame of the signal to be compensated according to the rough frequency offset estimation value and the residual frequency offset estimation value to obtain a compensated signal.

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