CN107994921B - Signal capturing method under high-dynamic low-signal-to-noise-ratio environment - Google Patents
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- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/69—Spread spectrum techniques
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/69—Spread spectrum techniques
- H04B1/707—Spread spectrum techniques using direct sequence modulation
- H04B1/709—Correlator structure
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/69—Spread spectrum techniques
- H04B1/713—Spread spectrum techniques using frequency hopping
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/69—Spread spectrum techniques
- H04B1/713—Spread spectrum techniques using frequency hopping
- H04B1/7156—Arrangements for sequence synchronisation
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/69—Spread spectrum techniques
- H04B2001/6904—Spread spectrum techniques using code hopping
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/69—Spread spectrum techniques
- H04B1/713—Spread spectrum techniques using frequency hopping
- H04B1/7156—Arrangements for sequence synchronisation
- H04B2001/71563—Acquisition
Abstract
The invention provides a signal capturing method under the environment of high dynamic and low signal-to-noise ratio, which is suitable for a spread spectrum or spread frequency hopping system, and comprises the following steps: s1: decomposing long-time data into N sub-data sections, and performing coherent integration on the sub-data sections and local codes with corresponding lengths through a correlator to obtain N groups of integral values, wherein N is a power number of 2; s2: determining K groups of time domain interpolation values according to the frequency analysis range of the FFT and the required frequency domain analysis range, and carrying out interpolation operation on N groups of integral values of the correlator on the time domain to obtain K groups of segment coherent interpolation value data for eliminating time domain gradient characteristics; s3: and performing coherent accumulation on each group of segmented coherent interpolation data to obtain the number of points required by FFT operation aiming at the obtained K groups of data, and performing K times of FFT operation according to the accumulation result to obtain frequency domain information. At least greatly reducing resource consumption.
Description
Technical Field
The invention relates to a spread spectrum frequency hopping communication and spread spectrum communication technology of aerospace products, in particular to a signal capture method under the environment of high dynamic and low signal to noise ratio.
Background
In the 70 s of the twentieth century, research on spread spectrum communication began domestically, and deeper theoretical research on direct sequence spread spectrum and frequency hopping technologies has been conducted until now. The military communication system in China is gradually changed from narrow-band communication and common frequency hopping to a more advanced direct sequence spread spectrum/frequency hopping mixed anti-interference technology system.
In terms of satellite communication and measurement and control, the spread spectrum technology is the most basic anti-interference technology in satellite communication. At present, the spread spectrum frequency hopping technology is widely applied to military and civil use, and particularly, the direct spread spectrum technology is widely applied to satellite communication systems, such as spread spectrum measurement signals in a navigation system and a spread spectrum measurement and control system.
The direct sequence spread/frequency hopping measurement and control system which is finished at present in China improves the anti-interference capability of the system by one level, and the technical indexes have certain precedence at home and abroad. The method mainly adopts a sliding correlation algorithm and a matched filtering algorithm to realize the capture synchronization of the spread-hopping mixed signal. Because the correlator of the spread spectrum frequency hopping and spread spectrum system has higher complexity, and simultaneously, the correlation event is longer due to the purpose of anti-interference communication, and under the condition that processing resources are limited, in order to obtain high coherent integral gain, the high dynamic application scene of the system cannot be considered.
Disclosure of Invention
The invention aims to provide a signal capturing method under the environment with high dynamic and low signal-to-noise ratio, thereby greatly reducing resource consumption.
In order to solve the above problems, the present invention provides a signal capturing method under the environment of high dynamic and low signal-to-noise ratio, which is suitable for a spread spectrum or spread frequency hopping system, and the method comprises the following steps:
s1: decomposing long-time data into N sub-data sections, and performing coherent integration on the sub-data sections and local codes with corresponding lengths through a correlator to obtain N groups of integral values, wherein N is a power number of 2;
s2: determining K groups of time domain interpolation values according to the frequency analysis range of the FFT and the required frequency domain analysis range, and carrying out interpolation operation on N groups of integral values of the correlator on the time domain to obtain K groups of segment coherent interpolation value data for eliminating time domain gradient characteristics;
s3: and performing coherent accumulation on each group of segmented coherent interpolation data to obtain the number of points required by FFT operation aiming at the obtained K groups of data, and performing K times of FFT operation according to the accumulation result to obtain frequency domain information.
According to an embodiment of the present invention, after obtaining the frequency domain information through the FFT operation in step S3, recording the maximum value, and recording the pseudo code phase and the carrier doppler value of the maximum value;
the method further includes step S4: repeating steps S1-S3 to complete the search after traversing the time uncertainty of the spread spectrum or spread frequency hopping system, comparing the obtained maximum values, and determining the pseudo code phase and the carrier Doppler value.
According to an embodiment of the present invention, the method further includes step S5, using the result captured in step S4, to narrow down both the time domain and frequency domain feature quantities to a smaller range, and performing secondary capture.
According to an embodiment of the present invention, the step S1 is preceded by the following steps:
s11: storing the sampled data in a local cache;
s12: after capture starts, a high-speed clock is adopted to read data from the local cache in a segmented and parallel manner, the data is read in at least two segments in a parallel manner, and the read data and a carrier are mixed to obtain down-conversion data; wherein the high speed clock ensures that the segment time is below the signal acquisition time.
According to an embodiment of the present invention, after the step S12 and before the step S1, the method further includes the following steps:
s13: and extracting the down-converted data according to a half chip to reduce the sampling rate, and taking the obtained reduced sampling rate as the long-time data.
According to an embodiment of the present invention, in the step S1, a corresponding number of correlators are selected according to the number of segment reads in the step S12, and the fractional data segment is coherently integrated with the local code of the corresponding length.
According to an embodiment of the present invention, in step S1, the integration length T of each fractional data segment is m half chips, m is a positive integer, where the integration length T satisfies T × N ═ T; in coherent integration, each fractional data segment is stepped through a half-chip search.
According to an embodiment of the present invention, in step S1, the maximum time domain offset of the signal in the full integration period is calculated according to the dynamic range of the signal, and the length range of the correlation integral of each fractional data segment is set to be expanded on the basis of m half chips according to the maximum time domain offset.
According to an embodiment of the present invention, in the step S2, during the interpolation operation, a phase rotation of the correlation peak is compensated, where the phase rotation is Δ f × Δ t, where Δ f is a doppler frequency offset, and Δ t is a time domain offset of the interpolation point.
According to an embodiment of the present invention, in step S3, according to the number I required by the FFT operation, a certain number of segmented coherent interpolation data is selected for coherent accumulation operation, and in each group of data, coherent accumulation is performed every N/I.
After the technical scheme is adopted, compared with the prior art, the invention has the following beneficial effects:
1. long-time coherent integration is decomposed into multi-segment segmented integration to ensure the correlation gain in each segment, meanwhile, the residence time of each search is reduced through parallel reading of data, and the search speed is increased;
2. by adopting a method of combining segmented integration with time domain interpolation, the time domain gradient characteristic of the signal can be compensated in the time domain, so that the problem that the output of a correlator drifts along with time due to the time domain Doppler characteristic of the signal is solved;
3. the segmented coherent output of the cancellation frequency domain gradual change characteristic is further segmented and accumulated, FFT time domain analysis is carried out, frequency domain information and coherent integral output are obtained, and equivalent frequency domain correlator expansion is achieved;
4. in order to avoid the influence of signal dynamic introduction under the condition of long-time integration, the receiver firstly carries out quick coarse acquisition and carries out fine acquisition of a second stage by using a result of the coarse acquisition stored locally so as to adapt to the dynamic change of the signal in the acquisition process.
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Fig. 1 is a schematic flow chart of a signal acquisition method under a high dynamic low snr environment according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a signal processing flow according to an embodiment of the present invention;
FIG. 3 is a schematic flow chart illustrating a signal acquisition method under a high dynamic low SNR environment according to another embodiment of the present invention;
fig. 4 is a schematic diagram of a position shift of a time domain correlation peak according to an embodiment of the invention.
Detailed Description
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, but rather construed as limited to the embodiments set forth herein.
Referring to fig. 1, in one embodiment, a signal acquisition method in a high dynamic low snr environment is applied to a spread spectrum or spread frequency hopping system, and the method includes the following steps:
s1: decomposing long-time data into N sub-data sections, and performing coherent integration on the sub-data sections and local codes with corresponding lengths through a correlator to obtain N groups of integral values, wherein N is a power number of 2;
s2: determining K groups of time domain interpolation values according to the frequency analysis range of the FFT and the required frequency domain analysis range, and carrying out interpolation operation on N groups of integral values of the correlator on the time domain to obtain K groups of segment coherent interpolation value data for eliminating time domain gradient characteristics;
s3: and performing coherent accumulation on each group of segmented coherent interpolation data to obtain the number of points required by FFT operation aiming at the obtained K groups of data, and performing K times of FFT operation according to the accumulation result to obtain frequency domain information.
In high dynamic operating conditions, large-scale parallel expansion in the frequency domain is often required for the requirements of spread spectrum frequency hopping communication (or spread spectrum communication) under weak signal or interference conditions. Especially for the requirement of low-rate anti-interference communication in a severe communication environment, coherent integration is often required to be performed on a millisecond time length to ensure the communication capability, so that a plurality of correlators need to be deployed in a frequency domain to ensure the correlation gains of signals on different frequencies, and the signals are ensured to be captured quickly. The invention is suitable for a spread spectrum frequency hopping communication system in a high dynamic environment, a pure spread spectrum communication system under a weak signal or interference condition and the like, realizes high-efficiency parallel expansion on a frequency domain through a related post-interpolation algorithm so as to compress resource consumption, and reduces the resource consumption by at least 1 order of magnitude compared with the traditional parallel expansion mode.
In step S1, the long time data, which has of course been stored in the local cache, is broken down into N partial data segments; after decomposition, the partial data segment and the local code with the corresponding length are subjected to coherent integration through a correlator to obtain N groups of integral values, wherein N is a power number of 2. The local code is a short code or a long code preset by the receiver, and the length of the selected local code is consistent with that of the corresponding sub data segment during coherent integration calculation. After the correlation integral is calculated, N groups of integral values with the same number as the sub data segments are obtained.
In step S2, K sets of time domain interpolation are determined according to the frequency analysis range of FFT (fast fourier transform) and the required frequency analysis range, which is set as needed and is larger than the frequency analysis range of FFT, so that the desired interpolation effect can be obtained, for example, K is a/b and rounded, a is the required frequency analysis range, and b is the frequency analysis range of FFT; and carrying out interpolation operation on N groups of integral values of the correlator on a time domain to obtain K groups of segment coherent interpolation value data for eliminating time domain gradient characteristics. The specific interpolation operation can refer to the interpolation operation process in the existing signal processing mode.
Considering the time domain gradient characteristic under the high dynamic condition, the correlation range of each segment of coherent integration needs to additionally consider time domain redundancy; and aiming at each frequency range in the dynamic range, performing interpolation operation on the correlator output in the time domain to obtain the segmented coherent output for eliminating the time domain gradient characteristic.
In step S3, for the K sets of obtained data, performing coherent accumulation on each set of segmented coherent interpolation data to obtain the number of points required for FFT operation, and performing K times of FFT operations according to the accumulation result to obtain frequency domain information.
Of course, the present invention can be further extended based on steps S1-S3, such as preprocessing of long-time data, compensation of signals, etc., and can be adjusted appropriately according to different systems or conditions.
The following describes embodiments of the present invention in more detail, and takes an anti-interference communication system using an aperiodic long code as a spreading code and performing communication in cooperation with high-speed frequency hopping as an example, and develops with reference to fig. 1-4.
The embodiment of the invention can divide the capturing and searching process into two stages, wherein the first stage is a quick coarse capturing stage, and the frequency and the time domain characteristic quantity of signals possibly drift in the coarse capturing and searching process, so that the related information of coarse capturing cannot be directly used for tracking, and therefore, the fine capturing is preferably carried out on the basis of the prior information.
The fast coarse acquisition is described first:
step S11 is executed first, and the data sampled by the ADC is stored in the local buffer, for example, the data with the data length T equal to 10ms is stored. The sampled data may be an intermediate frequency input signal received by the receiver, and the local buffer is a buffer module of the receiver.
Step S12 is executed, after the capture starts, a high-speed clock is adopted to read data from the local cache in a segmented and parallel mode, the data are read in at least two segments in a parallel mode, and the read data and a carrier wave are mixed to obtain down-conversion data; the high-speed clock ensures that the segmentation time is lower than the signal acquisition time, divides the data into at least two segments, and ensures that the processing time is lower than the signal acquisition time, otherwise, the capture time cannot be effectively reduced. And after frequency mixing with a debounce complex carrier generated according to local time, I, Q two paths of fundamental frequency data after orthogonal down-conversion are obtained.
To reduce the sampling rate, step S13 may be executed next, the down-converted data is decimated by half chip to reduce the sampling rate, and the resulting reduced sampling rate is used as the long-time data.
Of course, in the case where long-time data has been obtained, the steps S11-S13 are also not necessary. After the segmentation is performed in step S12, the number of segments divided in the subsequent processing may still be used, for example, in the correlation, a correlator may be selected according to the number of segments divided in step S12, and the correlator is spread in parallel by a plurality of correlators, so as to reduce the time overhead of a single operation and reduce the dwell time of a single scan.
Step S1 is executed to divide the down-sampled data into N segments, correlate the N segments with the local codes of consecutive corresponding lengths, and obtain N groups of integrated values, where N is 1024 in this embodiment. Preferably, in step S1, the integration length T of each fractional data segment is m half chips, m is a positive integer, where the integration length T satisfies T × N ═ T; in coherent integration, if the system is a frequency hopping system, the signal in the integration length should not be affected by frequency hopping.
In order to meet the subsequent time domain interpolation requirement, the range of each small segment of coherent integration should be extended. Preferably, in step S1, the time domain maximum offset of the signal in the full integration period is calculated according to the dynamic range of the signal, and the length range of the correlation integral of each fractional data segment is set to be expanded on the basis of m half chips according to the time domain maximum offset.
The maximum time domain offset of the signal in the full integration period can be calculated according to the dynamic state, and if the maximum time domain offset is n half chips, the correlation output range of each small segment should include [ -n-m + n ]]So that the correlation output per bin is calculated as m +2 n. Since the entire correlation time T includes N segments, a total of (m +2N) × N correlation output values are calculated for each segment (time uncertainty is m half chips), and a total of (m +2N) × N correlation output values are calculated for each segment. For high-speed frequency hopping system, 1/5T is requiredFHStep by step, step N is 5T/TFHThen, the search within each segment is stepped by a half-chip search, and each segment has m half-chips, which is also (m +2N) × N outputs in total.
In order to increase the processing speed, the data should be processed in parallel in combination with the segmented parallel processing manner of step S12, that is, in step S1, a corresponding number of correlators are selected according to the number of segmented reads in step S12, and the fractional data segment and the local code of the corresponding length are coherently integrated in parallel.
Next, step S2 is executed to perform time-domain interpolation on the obtained result according to the time-domain drift calculation of the correlation position in the range where the frequency domain is required to be expanded. Since the integration period T is short, it is assumed that the influence of the doppler change on the integration is not considered (or only the mean value thereof is considered) during the full integration period, and only the inherent frequency offset is considered. Due to the influence of the doppler effect in the time domain, the position of the correlation peak in the segment correlation output is shifted with time in the integration period. The time domain drift is shown in fig. 4, and due to the drift of the correlation peak position along with time, coherent accumulation gain in the full integration period cannot be obtained by directly performing coherent accumulation on the N groups of correlation peaks. Therefore, the time domain needs to be interpolated according to the frequency domain analysis, and the interpolation preferably adopts two-point linear interpolation. The result of the time domain linear interpolation is equivalent to spreading out a plurality of correlators in the frequency domain, thereby greatly reducing the resource consumption.
Because the time domain drift caused by doppler also causes phase rotation of the correlation peak, compensation of phase rotation is required to be included in the interpolation operation. Preferably, in step S2, during the interpolation operation, the phase rotation of the correlation peak is compensated, where the phase rotation value is Δ f × Δ t, where Δ f is the doppler frequency offset and Δ t is the time domain offset of the interpolation point.
Preferably, in step S3, according to the number I of points required for FFT operation, a certain number of segmented coherent interpolation data is selected for coherent accumulation operation, and in each group of data, coherent accumulation is performed every N/I.
In a specific example, the full integration period is 10ms, the frequency domain analysis precision of the integrated output is 1/T-100 Hz, in this example, the final FFT analysis is 64 points, and the frequency analysis range is 6.4K. Meanwhile, in this example, if the frequency domain analysis range is required to be 100K, 16 sets of time domain interpolation (100/6.4 is 15.625, rounding) are required. The operation is equivalent to the expansion of 16 correlators in the frequency domain (a plurality of correlators are required to be expanded in the frequency domain according to the integration time length and the frequency domain analysis range in the traditional processing mode), and the storage and low-speed calculation (the half-chip calculation rate is reduced to one m-th from the half-chip calculation rate) are equivalent to the expansion of 16 high-speed correlators in the frequency domain, so that the order of magnitude is reduced, and the consumption of operation and logic resources is greatly reduced. In the application occasion with wider frequency domain analysis range, the resource optimization degree can be further improved.
In the interpolation process, phase compensation is required to be correspondingly performed according to the time domain shift of the interpolation point, the number of relevant points after interpolation is changed into 16 × m × N, and the number of points sent to frequency domain analysis is 16 × m × N × 64. If the system is a coherent frequency hopping system, the influence of doppler is not only considered in phase compensation, but also the influence of frequency hopping initial position deviation on the carrier wave needs to be compensated. Typically, an optimal sample point traversal is required to obtain an accuracy analysis of 1/32 chips, in this case a total of 16 sets of plus and minus 1/4 chip ranges. In this example, the integrated output for each set of bins is coherently accumulated every N/64 to yield 16 × m × N × 64 integrated values.
Next, step S3 is executed, and preferably, after obtaining the frequency domain information through the FFT operation in step S3, the maximum value is recorded, and the pseudo code phase and the carrier doppler value of the maximum value are recorded. Specifically, 16 times of 64-point FFT are performed on each of the obtained 16 groups of 64-point values, the maximum value is stored, and the maximum value pseudo code phase and the carrier doppler value are recorded.
Preferably, the method further includes step S4: repeating steps S1-S3 to complete the search after traversing the time uncertainty of the spread spectrum or spread frequency hopping system, comparing the obtained maximum values, and determining the pseudo code phase and the carrier Doppler value.
Preferably, the method further includes a step S5 of narrowing down both the time domain and frequency domain feature quantities to a smaller range by using the result of the capturing in the step S4, and performing secondary capturing. Because the frequency and the time domain characteristic quantity of the signal may drift in the course of coarse acquisition and search, the related information of coarse acquisition cannot be directly used for tracking, fine acquisition needs to be performed on the basis of the prior information, and at the moment, the time domain and the frequency domain characteristic quantity are both narrowed to a very small range, so that rapid acquisition can be performed, tracking is guided, and the fine acquisition of the second stage is realized.
The invention has good universality and good portability. The invention can be applied to the design and development of aerospace type single-machine products of the same type, reduces the development period of the single machine and meets the requirement of continuously improved reliability.
Although the present invention has been described with reference to the preferred embodiments, it is not intended to limit the scope of the claims, and those skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention.
Claims (9)
1. A signal capture method under the environment of high dynamic and low signal-to-noise ratio is suitable for a spread spectrum or spread frequency hopping system, and is characterized by comprising the following steps:
s1: decomposing long-time data into N sub-data sections, and performing coherent integration on the sub-data sections and local codes with corresponding lengths through a correlator to obtain N groups of integral values, wherein N is a power number of 2;
s2: determining K groups of time domain interpolation values according to the frequency analysis range of the FFT and the required frequency domain analysis range, and carrying out interpolation operation on N groups of integral values of the correlator on the time domain to obtain K groups of segment coherent interpolation value data for eliminating time domain gradient characteristics;
s3: for the obtained K groups of data, carrying out coherent accumulation on each group of segmented coherent interpolation data to obtain the number of points required by FFT operation, and carrying out K times of FFT operation according to the accumulation result to obtain frequency domain information;
in step S2, during the interpolation operation, the phase rotation of the correlation peak is compensated, where the rotation value of the phase is Δ f × Δ t, where Δ f is the doppler frequency offset, and Δ t is the time domain offset of the interpolation point;
after the FFT operation in step S3 obtains the frequency domain information, the maximum value is recorded, and the pseudo code phase and the carrier doppler value of the maximum value are recorded.
2. The method for signal acquisition under environment with high dynamic and low snr as recited in claim 1, further comprising step S4: repeating steps S1-S3 to complete the search after traversing the time uncertainty of the spread spectrum or spread frequency hopping system, comparing the obtained maximum values, and determining the pseudo code phase and the carrier Doppler value.
3. The signal capturing method under the environment of high dynamic and low snr as recited in claim 2, further comprising step S5, utilizing the capturing result of step S4 to narrow the time domain and frequency domain feature quantities to a smaller range for secondary capturing.
4. The method for signal acquisition under an environment with high dynamic and low signal-to-noise ratio as claimed in claim 1, wherein said step S1 is preceded by the steps of:
s11: storing the sampled data in a local cache;
s12: after capture starts, a high-speed clock is adopted to read data from the local cache in a segmented and parallel manner, the data is read in at least two segments in a parallel manner, and the read data and a carrier are mixed to obtain down-conversion data; wherein the high speed clock ensures that the segment time is below the signal acquisition time.
5. The method for signal acquisition under high dynamic low signal-to-noise ratio environment as claimed in claim 4, wherein after the step S12 and before the step S1, the method further comprises the steps of:
s13: and extracting the down-converted data according to a half chip to reduce the sampling rate, and taking the obtained reduced sampling rate as the long-time data.
6. The method for signal acquisition under high dynamic low SNR environment as claimed in claim 4, wherein in step S1, a corresponding number of correlators are selected according to the number of segmented reads in step S12, and the fractional data segment is coherently integrated with a local code of corresponding length.
7. The signal capturing method in high dynamic low snr environment according to any one of claims 1 to 6, wherein in step S1, an integral length T of each fractional data segment is m half chips, m is a positive integer, where the integral length T satisfies T × N ═ T, and T is a stored data length; in coherent integration, each fractional data segment is stepped through a half-chip search.
8. The signal acquisition method under high-dynamic low signal-to-noise ratio environment as claimed in claim 7, wherein in step S1, the maximum offset in time domain of the signal in the full integration period is calculated according to the dynamic range of the signal, and the length range of the correlation integral of each fractional data segment is set to be expanded according to the maximum offset in time domain on the basis of m half chips.
9. The method as claimed in any one of claims 1 to 6, wherein in step S3, according to the number of points I required for FFT operation, the segmented coherent interpolation data with a certain number of points is selected for coherent accumulation operation, and in each group of data, coherent accumulation is performed every N/I.
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| CN109752740A (en) * | 2018-12-28 | 2019-05-14 | 航天信息股份有限公司 | A kind of method and system carrying out signal capture using multi-access-like segment correlation and FFT |
| CN112865925A (en) * | 2021-02-01 | 2021-05-28 | 西安思丹德信息技术有限公司 | FPGA-based high-dynamic low-signal-to-noise ratio capture algorithm |
| CN113810080B (en) * | 2021-09-16 | 2022-07-01 | 中国电子科技集团公司第五十四研究所 | Low-carrier-to-noise-ratio large-capacity short-burst spread spectrum signal rapid capturing device |
| CN113972929B (en) * | 2021-10-26 | 2023-03-24 | 上海无线电设备研究所 | Method for capturing spread spectrum signal under high dynamic Doppler |
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