Method and device for capturing two-stage search of spread frequency hopping signals

Abstract

The present invention provides a capture method and device for two-stage search of spread frequency hopping signals, the method comprising: receiving spread frequency hopping signals, and performing down-conversion processing on the spread frequency hopping signals to obtain processed signals; performing first-stage Doppler search on the processed signals based on a first preset search number of times to obtain a first search signal; despreading the first search signal to obtain a despread signal; performing intra-hop coherent accumulation on the despread signal to obtain a first accumulated signal; performing second-stage Doppler search on the first accumulated signal based on a second preset search number of times to obtain a second search signal; performing inter-hop phase compensation on the second search signal to obtain a compensated signal; performing inter-hop coherent accumulation on the compensated signal to obtain a second accumulated signal; determining a peak value of the second accumulated signal; comparing the magnitude relationship between the peak value and a preset threshold value, and determining a capture result of the spread frequency hopping signal based on the magnitude relationship, thereby reducing resource occupation.

Description

Technical Field

[0001] The present invention relates to the field of wireless communication technology, and in particular to a method and device for capturing a spread frequency hopping signal in two-stage search. Background Art

[0002] Spread-hop signals are widely used due to their excellent anti-interference performance. The capture of spread-hop signals is a key step in the communication synchronization process, and its purpose is to accurately identify and track the frequency hopping mode and spread spectrum code of the transmitter at the receiving end.

[0003] The acquisition method of the spread-hop system signal needs to complete the Doppler search. The Doppler search is used to compensate for the frequency offset caused by relative motion. The existing Doppler search method needs to search the spread-hop system signal multiple times to determine the best frequency compensation value, which usually involves searching for each possible Doppler offset of the spread-hop system signal, resulting in a large amount of calculation, occupying too many resources, and failing to meet actual needs. Summary of the invention

[0004] The present invention provides a two-stage search capture method and device for spread hopping frequency signals, which are used to solve the technical problem of large resource occupation when capturing spread hopping system signals in the prior art.

[0005] On the one hand, the present invention provides a method for capturing a spread frequency hopping signal by two-stage search, comprising:

[0006] receiving a frequency-hopping spread signal, and performing down-conversion processing on the frequency-hopping spread signal to obtain a processed signal;

[0007] Based on a first preset search number, performing a first level Doppler search on the processed signal to obtain a first search signal;

[0008] Despreading the first search signal to obtain a despread signal;

[0009] Performing intra-hop coherent accumulation on the despread signal to obtain a first accumulated signal;

[0010] Based on a second preset search number, performing a second level Doppler search on the first accumulated signal to obtain a second search signal; wherein the second preset search number is a ratio of a preset number to the first preset search number, and the preset number is greater than the first preset search number;

[0011] performing inter-hop phase compensation on the second search signal to obtain a compensated signal;

[0012] Performing inter-hop coherent accumulation on the compensation signal to obtain a second accumulated signal;

[0013] determining a peak value of the second accumulated signal;

[0014] The magnitude relationship between the peak value and a preset threshold value is compared, and based on the magnitude relationship, a capture result of the spread hopping frequency signal is determined.

[0015] According to a two-stage search acquisition method for a spread frequency hopping signal provided by the present invention, before despreading the first search signal to obtain a despread signal, the method further includes:

[0016] The data integration of the first search signal is down-speeded to 2 times the code rate.

[0017] According to a two-stage search acquisition method for a spread frequency hopping signal provided by the present invention, despreading the first search signal to obtain a despread signal includes:

[0018] performing correlation processing on the first search signal using a predefined spread spectrum code;

[0019] determining a frequency hopping pattern in a current frequency hopping period in the first search signal based on the spreading code;

[0020] Applying a frequency hopping pattern to the first search signal to perform frequency hopping compensation based on the frequency hopping pattern;

[0021] The first search signal after frequency hopping compensation is despread to obtain a despread signal.

[0022] According to a two-stage search acquisition method for spread frequency hopping signals provided by the present invention, the intra-hop coherent accumulation is to accumulate signals within the same frequency hopping period;

[0023] The inter-hop coherent accumulation is to accumulate signals within multiple frequency hopping periods.

[0024] A two-stage search acquisition method for a spread frequency hopping signal provided by the present invention also includes:

[0025] When performing a first-level Doppler search on the processed signal, determining a conversion relationship between carrier Doppler and code Doppler;

[0026] Based on the conversion relationship, the code chip slide is controlled not to exceed 0.25 code chip period.

[0027] According to a two-stage search acquisition method for a spread frequency hopping signal provided by the present invention, the threshold value is set in the following manner:

[0028] The threshold value is set according to the characteristics of the spread hopping frequency signal and / or noise.

[0029] According to a two-stage search acquisition method for a spread frequency hopping signal provided by the present invention, the threshold value is set according to the characteristics of the spread frequency hopping signal and / or noise, comprising:

[0030] If it is detected that the noise level of the spread frequency hopping signal increases, or if no valid signal peak of the spread frequency hopping signal is detected within a preset time period, the threshold value is increased;

[0031] If the characteristics of the spread frequency hopping signal indicate that the signal strength exceeds a preset strength, or if a signal peak value is continuously detected within a preset time period, the threshold value is lowered.

[0032] According to a two-stage search capture method for a spread frequency hopping signal provided by the present invention, determining the capture result of the spread frequency hopping signal based on the size relationship includes:

[0033] When the magnitude relationship is such that the peak value exceeds the threshold value, it is confirmed that the spread frequency hopping signal is captured successfully;

[0034] When the magnitude relationship is that the peak value is lower than the threshold, it is confirmed that the spread hopping signal is not captured successfully, and the process returns to the step of performing a first-level Doppler search on the processed signal based on the first preset search times to obtain a first search signal.

[0035] According to a two-stage search acquisition method for a spread frequency hopping signal provided by the present invention, after receiving the spread frequency hopping signal, the method may further include:

[0036] The received spread frequency hopping signal is buffered.

[0037] On the other hand, the present invention also provides a capture device for two-stage search of spread frequency hopping signals, comprising:

[0038] A down-conversion module is used to receive the spread-hopping frequency signal and perform down-conversion processing on the spread-hopping frequency signal to obtain a processed signal;

[0039] A first-level search module, configured to perform a first-level Doppler search on the processed signal based on a first preset search number to obtain a first search signal;

[0040] A despreading module, used for despreading the first search signal to obtain a despread signal;

[0041] A first accumulation module, used for performing intra-hop coherent accumulation on the despread signal to obtain a first accumulated signal;

[0042] A second-level search module, used to perform a second-level Doppler search on the first accumulated signal based on a second preset search number to obtain a second search signal; wherein the second preset search number is a ratio of the preset number to the first preset search number, and the preset number is greater than the first preset search number;

[0043] A compensation module, used for performing inter-hop phase compensation on the second search signal to obtain a compensated signal;

[0044] A second accumulation module, used for performing inter-hop coherent accumulation on the compensation signal to obtain a second accumulated signal;

[0045] A peak value determination module, used to determine the peak value of the second accumulated signal;

[0046] The capture result module is used to compare the magnitude relationship between the peak value and the preset threshold value, and determine the capture result of the spread hopping frequency signal based on the magnitude relationship.

[0047] On the other hand, the present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the capture method of the two-stage search for spread hopping signals as described above is implemented.

[0048] The invention provides a capture method and device for two-stage search of a spread frequency hopping signal. Based on a first preset search number, a first-stage Doppler search is performed on a processed signal to obtain a first search signal; the first search signal is despread to obtain a despread signal; the despread signal is coherently accumulated within a hop to obtain a first accumulated signal; based on a second preset search number, a second-stage Doppler search is performed on the first accumulated signal to obtain a second search signal; inter-hop phase compensation is performed on the second search signal to obtain a compensated signal; inter-hop coherent accumulation is performed on the compensated signal to obtain a second accumulated signal; a peak value of the second accumulated signal is determined; the magnitude relationship between the peak value and a preset threshold value is compared, and based on the magnitude relationship, a capture result of the spread frequency hopping signal is determined, thereby reducing the occupation of resources in the signal capture process, thereby optimizing system performance and improving system operation efficiency. In addition, through two-stage Doppler search and coherent accumulation, the capture performance and accuracy of the spread frequency hopping signal are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0050] Figure 1 It is a flow chart of a two-stage search acquisition method for a spread frequency hopping signal provided by an embodiment of the present invention;

[0051] Figure 2 is a waveform diagram of a spread frequency hopping signal provided by an embodiment of the present invention;

[0052] Figure 3 is a schematic diagram of a spread frequency hopping signal acquisition process provided by an embodiment of the present invention;

[0053] Figure 4It is a structural schematic diagram of a capture device for two-stage search of spread frequency hopping signals provided by an embodiment of the present invention;

[0054] Figure 5 It is a schematic diagram of the structure of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0055] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0056] Figure 1 The figure is a flow chart of the capture method of the two-stage search of the spread frequency hopping signal provided by the embodiment of the present invention. The spread frequency hopping signal can also be regarded as a spread frequency hopping system signal. The present invention is also applicable to the fast frequency hopping signal of the continuous phase, that is, the present invention can replace the spread frequency hopping signal with the fast frequency hopping signal of the continuous phase.

[0057] See also Figure 1 The acquisition method of the two-stage search for the spread frequency hopping signal may include the following steps 101 to 109.

[0058] 101. Receive a spread frequency hopping signal, and perform down-conversion processing on the spread frequency hopping signal to obtain a processed signal.

[0059] In this step, down-conversion processing is to convert the spread-hop signal into a baseband signal so that it is compatible with subsequent signal processing hardware and algorithms for further processing and analysis. After the spread-hop signal is down-converted, the frequency of the signal is reduced, making it easier to demodulate, for example, easier to despread and de-hop.

[0060] 102. Based on a first preset search number, perform a first level Doppler search on the processed signal to obtain a first search signal.

[0061] In this step, the first-level Doppler search may specifically include Doppler search, frequency slotting and signal processing.

[0062] Doppler search: This step involves estimating the Doppler shift of the received signal. The purpose of the Doppler search is to determine the frequency offset of the signal, which is usually caused by the relative motion between the signal source and the receiver. In the first level of Doppler search, the system will search the signal frequency according to the first preset search number (i.e. K2 times) to find possible Doppler shift values.

[0063] Frequency slotting: In the first level search, the system may test multiple frequency points within a certain range, which are called "frequency slotting". The system will perform correlation operations on each frequency point to determine whether the signal exists at these frequency points.

[0064] Signal processing: After finding the possible Doppler frequency shift, the system will perform corresponding frequency compensation on the signal to eliminate or reduce the influence of the Doppler effect, thereby obtaining the first search signal.

[0065] 103. Despread the first search signal to obtain a despread signal.

[0066] In this step, despreading the first search signal to obtain a despread signal may include:

[0067] Performing correlation processing on the first search signal using a predefined spread spectrum code; wherein the correlation length of the correlation processing may be 1 bit length;

[0068] determining a frequency hopping pattern in a current frequency hopping period in the first search signal based on the spread spectrum code;

[0069] Applying a frequency hopping pattern to the first search signal to perform frequency hopping compensation based on the frequency hopping pattern;

[0070] The first search signal after frequency hopping compensation is despread to obtain a despread signal.

[0071] The accuracy and reliability of the despread signal are improved by using predefined spread spectrum codes for correlation processing and frequency hopping compensation.

[0072] 104. Perform intra-hop coherent accumulation on the despread signal to obtain a first accumulated signal.

[0073] In this step, intra-hop coherent accumulation is to accumulate the signals within the same frequency hopping period. Through intra-hop coherent accumulation, the energy of the signal can be enhanced and the influence of noise can be reduced. The accumulation is based on the phase and frequency information of the signal to ensure that the accumulated signal is coherent.

[0074] 105. Based on a second preset search number, perform a second level Doppler search on the first accumulated signal to obtain a second search signal, wherein the second preset search number is a ratio of the preset number to the first preset search number, and the preset number is greater than the first preset search number.

[0075] In this step, in the second-level Doppler search, frequency slotting can be used, that is, within the frequency range determined by the first-level search, the frequency points are further subdivided for search, so that the signal can be tested at a smaller frequency interval to determine a more accurate Doppler shift. The preset number can be represented by K1, that is, the second preset search number is K1 / K2.

[0076] The second-level Doppler search is performed after the despread signal is coherently accumulated within a hop, which can significantly reduce the amount of data processing.

[0077] 106. Perform inter-hop phase compensation on the second search signal to obtain a compensated signal.

[0078] In this step, after the second level Doppler search, the second search signal is obtained. Since the signal may experience different Doppler frequency shifts during the frequency hopping process, phase compensation is required for these signals. The purpose of phase compensation is to adjust the phase of the signal to ensure the continuity and consistency of the signal.

[0079] 107. Perform inter-hop coherent accumulation on the compensation signal to obtain a second accumulated signal.

[0080] In this step, the inter-hop coherent accumulation is to accumulate the signals within multiple frequency hopping periods.

[0081] 108. Determine a peak value of the second accumulated signal.

[0082] In this step, the peak usually represents the strongest part of the signal and is also the most likely location for the signal to exist.

[0083] 109. Compare the magnitude relationship between the peak value and a preset threshold value, and determine the capture result of the spread hopping frequency signal based on the magnitude relationship.

[0084] In this embodiment, based on a first preset search number, a first-level Doppler search is performed on the processed signal to obtain a first search signal; the first search signal is despread to obtain a despread signal; the despread signal is coherently accumulated within a hop to obtain a first accumulated signal; based on a second preset search number, a second-level Doppler search is performed on the first accumulated signal to obtain a second search signal; inter-hop phase compensation is performed on the second search signal to obtain a compensated signal; inter-hop coherent accumulation is performed on the compensated signal to obtain a second accumulated signal; the peak value of the second accumulated signal is determined; the magnitude relationship between the peak value and the preset threshold value is compared, and based on the magnitude relationship, the capture result of the spread hopping signal is determined, thereby reducing the resource occupation in the signal capture process, thereby optimizing system performance and improving the system operation efficiency. In addition, through two-level Doppler search and coherent accumulation, the capture performance and accuracy of the spread hopping signal are improved.

[0085] In an embodiment of the present specification, before despreading the first search signal to obtain a despread signal, the method may further include:

[0086] The data integration of the first search signal is down-speeded to 2 times the code rate.

[0087] In this embodiment, by reducing the data integration speed to 2 times the code rate, the amount of processed data is reduced, and the processing speed and efficiency are improved.

[0088] In an embodiment of the present specification, the acquisition method of the two-stage search for the spread frequency hopping signal may further include:

[0089] When performing the first level Doppler search on the processed signal, the conversion relationship between the carrier Doppler and the code Doppler is determined;

[0090] Based on the conversion relationship, the code chip slide is controlled not to exceed 0.25 code chip period.

[0091] In this embodiment, there is a conversion relationship between carrier Doppler and code Doppler. When the carrier Doppler search accuracy is higher, the code Doppler accuracy is higher. Generally, code Doppler can be calculated by carrier Doppler and the rate of spread spectrum code. Code Doppler affects the code chip sliding and causes despreading loss. According to theoretical analysis, when the maximum code chip sliding reaches 0.25 code chip period during the accumulation time, the despreading loss is about 1dB. By determining the conversion relationship between carrier Doppler and code Doppler and controlling the code chip sliding not to exceed 0.25 code chip period, the despreading loss is reduced and the accuracy of signal despreading is improved.

[0092] In an embodiment of the present specification, determining a capture result of a spread frequency hopping signal may include:

[0093] When the magnitude relationship is that the peak value exceeds the threshold, it is confirmed that the spread hopping signal is captured successfully;

[0094] When the peak value is lower than the threshold value, it is confirmed that the spread hopping signal is not captured successfully, and the process returns to the step of performing a first-level Doppler search on the processed signal based on the first preset search times to obtain a first search signal.

[0095] In one embodiment of the present specification, the threshold value is set in the following manner:

[0096] The threshold value is set according to the characteristics of the spread hopping frequency signal and / or noise.

[0097] In this embodiment, the threshold value is a dynamic value, which can change with the characteristics and noise of the spread hopping signal, so that the capture rule can be adjusted according to the actual situation, thereby improving the flexibility and accuracy of the capture. In general, the noise level in the received spread hopping signal can be estimated before the process of capturing the spread hopping signal begins or during the capture process, and the noise estimation can be achieved by measuring the background noise power in the spread hopping signal. The characteristics of the spread hopping signal can also be analyzed, such as the average power, bandwidth, hopping mode, etc. of the spread hopping signal, which can help determine the significance of the spread hopping signal in the noise background.

[0098] In an embodiment of the present specification, setting a threshold value according to the characteristics of the spread hopping signal and / or noise may include:

[0099] If it is detected that the noise level of the spread frequency hopping signal increases, or if no valid signal peak of the spread frequency hopping signal is detected within a preset time period, the threshold value is increased;

[0100] If the characteristics of the spread frequency hopping signal indicate that the signal strength exceeds a preset strength, or if a signal peak value is continuously detected within a preset time period, the threshold value is lowered.

[0101] In an embodiment of the present specification, after receiving the spread frequency hopping signal, the method may further include:

[0102] The received spread frequency hopping signal is buffered.

[0103] In this embodiment, by caching the received spread hopping signal, the access efficiency of the spread hopping signal can be improved and the spread hopping signal can be quickly processed. Generally, the received spread hopping signal can be cached in memory, and of course, it can also be cached in hardware or data structure.

[0104] The application scenario of the present invention is introduced as follows. The present invention is applicable to a fast frequency hopping signal with a continuous phase, and the fast frequency hopping signal can be expressed by the following formula (1).

[0105] (1); among which,

[0106] is the average power of the transmitted signal, Indicates the frequency hopping frequency; represents the RF reference frequency of the frequency hopping point, then the actual RF frequency hopping frequency is ; is the duration of a frequency hopping frequency; To take the real part operation; Indicates The spreading code within the frequency hopping frequency, , Indicates the pseudo code rate is Direct sequence spread spectrum code.

[0107] The frequency hopping waveform of the frequency hopping signal applicable to the present invention is as follows: Figure 2 As shown, the information rate of the spread frequency hopping signal transmission is Rb, and the duration of each information bit is Tb; the hopping rate of the frequency hopping signal is Rh, and the duration of each hop is Th; the rate of the spread spectrum code chip is Rc, and the duration of each code chip is Tc. It can be assumed that each information bit contains N frequency hops, and each hop signal has M code chips.

[0108] Capture principle: Since the receiving end does not know the frequency hopping code, spread spectrum code and Doppler of the current signal, it is necessary to complete the search for the spread spectrum code and Doppler through capture. The received signal can be expressed by the following formula (2).

[0109] (2); among which, is the received signal power, Indicates the presence of a spreading code with code Doppler, Indicates the time difference between sending and receiving signals. Indicates Doppler jump, Indicates The frequency hopping frequency. and carrier Doppler. Frequency Hopping Doppler Both code Doppler and signal Doppler can be calculated from carrier Doppler.

[0110] The locally generated signal can be expressed by the following formula (3).

[0111] (3). Among them, Indicates that the locally generated delay is The spread frequency hopping signal, is a locally generated spreading code with code Doppler and delay, is the delay of the locally generated signal, is the Doppler of the locally generated signal.

[0112] The locally generated signal and the received signal are correlated, and the correlation length may be 1 bit length. The result of the correlation operation can be referred to in the following formula (4). (4) Among them, It is the correlation operation result of the received signal and the locally generated signal.

[0113] To further illustrate, Figure 3 The received signal and the local signal exist for a certain period of time. The deviation is used to search for the local signal (with 0.5 chip as the step). After that, the received code chip is aligned with the local code chip, and a relatively large peak value will be obtained. At the same time, Doppler search is performed. When the local signal Doppler search value is consistent with the received Doppler, the correlation peak is the largest. Each code chip search and Doppler search will obtain a correlation value. The maximum value is found among all the correlation values. The code chip and Doppler corresponding to the maximum value are the capture results. The design of the spread spectrum code is coherent with the frequency hopping pattern, that is, the current frequency hopping pattern can be known according to the spread spectrum code, such as Figure 3 As shown in the figure, during the local pseudo code mobile search, the frequency hopping points move in sequence, so that the code chips c1~c MThe corresponding frequency hopping point is always f1, code c M+1 ~c 2M The corresponding frequency hopping frequency is always f2.

[0114] The following is an analysis of the performance loss caused by carrier Doppler search accuracy:

[0115] In order to achieve high-performance capture, coherent accumulation is used, and the accumulation length is 1 information bit. The Doppler search accuracy is mainly affected by the following two aspects.

[0116] Aspect 1: Phase change causes coherent accumulation loss. According to theoretical calculations, the carrier phase change caused by carrier Doppler causes coherent accumulation loss (dB) as follows (5):

[0117] (5).

[0118] The higher the frequency search accuracy, the smaller the coherent accumulation loss. In particular, when the frequency search accuracy reaches one-quarter of the information rate (causing a 90° carrier phase change), that is, , the capture loss is less than 1dB, so according to Frequency search is performed with high accuracy, thus achieving high performance capture accuracy. b It can represent the information bit rate or symbol rate, that is, the number of symbols transmitted per second.

[0119] Aspect 2: Carrier Doppler and code Doppler have a conversion relationship. The higher the carrier Doppler search accuracy, the higher the code Doppler accuracy. Code Doppler affects the chip slippage and causes despreading loss. According to theoretical analysis, when the maximum chip slippage reaches 0.25 chip cycles during the accumulation time, the despreading loss is about 1dB. Therefore, when searching for Doppler, it is necessary to ensure that the chip slippage is less than 0.25 chip cycles.

[0120] That is to say, the Doppler search accuracy is related to the accumulation time. The longer the accumulation time, the more performance loss will be caused by phase change and code chip sliding.

[0121] Generally speaking, carrier phase changes require higher Doppler search accuracy. For example, if a phase change of 90° requires K1 Doppler searches, and a chip slip of 0.25 requires K2 Doppler searches, then K1 will be tens to hundreds of times greater than K2. Therefore, according to the traditional Doppler search scheme, Doppler needs to search K1 times. When K1 is large, the capture resources increase dramatically.

[0122] Comparison of schemes: Assuming that the signal sampling rate is 2 times the code rate, 1 information bit contains 2×N×M data. Other schemes need to perform K1 Doppler searches on 2×N×M data, and the total amount of data to be processed is 2×N×M×K1; the scheme of the present invention performs K2 Doppler searches on 2×N×M data, and then performs intra-hop accumulation, and then performs K1 / K2 Doppler searches, so the total amount of data to be processed is 2×N×M×K2+N×K1. For example, in a typical scenario application, K1 is 100 times K2, K2 needs to be searched 50 times, each information bit contains 100 hops (ie, N=100), and each hop contains 500 chips (ie, M=500), so the amount of data processed by the scheme of the present invention is reduced by about 100 times.

[0123] In summary, the present invention has multiple beneficial effects. For example, before the code chip search, the integration speed is reduced to 2 times the code rate to reduce the data processing volume; considering that the influence of Doppler on the code element sliding is smaller than the influence on the phase, a two-level Doppler search is designed. During despreading, the frequency difference is required to be small, that is, the first-level frequency search is designed to be K2 times; the second-level frequency search is designed to be K1 / K2 times. Although the total number of two-level frequency searches is K1 times, the second-level frequency search is run after the integration speed reduction (intra-hop accumulation), which can significantly reduce the data processing volume; the capture algorithm is based on sliding correlation to complete the frequency hopping carrier stripping and direct spread code stripping, and then phase correction and coherent accumulation are performed. The success of the capture is judged based on the comparison of the accumulation result with the preset capture threshold, and the judgment result is relatively accurate. The present invention occupies less resources for Doppler search and has high efficiency.

[0124] Based on the same general inventive concept, the present invention also protects a capture device for two-stage search of spread frequency hopping signals, such as Figure 4 As shown, Figure 4 The structure diagram of the capture device for two-stage search of spread frequency hopping signals provided by an embodiment of the present invention is as follows. The capture device for two-stage search of spread frequency hopping signals provided by the present invention is described below. The capture device for two-stage search of spread frequency hopping signals described below and the capture method for two-stage search of spread frequency hopping signals described above can be referred to each other.

[0125] The capture device for two-stage search of spread hopping signals may include a down-conversion module 401, a first-stage search module 402, a despreading module 403, a first accumulation module 404, a second-stage search module 405, a compensation module 406, a second accumulation module 407, a peak determination module 408, and a capture result module 409.

[0126] The down-conversion module 401 is used to receive the spread frequency hopping signal and perform down-conversion processing on the spread frequency hopping signal to obtain a processed signal;

[0127] The first-stage search module 402 is used to perform a first-stage Doppler search on the processed signal based on a first preset search number to obtain a first search signal;

[0128] The despreading module 403 is used to despread the first search signal to obtain a despread signal;

[0129] The first accumulation module 404 is used to perform intra-hop coherent accumulation on the despread signal to obtain a first accumulated signal;

[0130] The second-stage search module 405 is used to perform a second-stage Doppler search on the first accumulated signal based on a second preset search number to obtain a second search signal; wherein the second preset search number is a ratio of the preset number to the first preset search number, and the preset number is greater than the first preset search number;

[0131] The compensation module 406 is used to perform inter-hop phase compensation on the second search signal to obtain a compensated signal;

[0132] The second accumulation module 407 is used to perform inter-hop coherent accumulation on the compensation signal to obtain a second accumulated signal;

[0133] The peak value determination module 408 is used to determine the peak value of the second accumulated signal;

[0134] The capture result module 409 is used to compare the magnitude relationship between the peak value and a preset threshold value, and determine the capture result of the spread hopping frequency signal based on the magnitude relationship.

[0135] Figure 5 Schematic diagram of the structure of an electronic device provided by an embodiment of the present invention. Figure 5 As shown, the electronic device may include: a processor 510, a communication interface 520, a memory 530 and a communication bus 540, wherein the processor 510, the communication interface 520 and the memory 530 communicate with each other via the communication bus 540. The processor 510 may call the logic instructions in the memory 530 to execute the acquisition method of the two-stage search of the spread hopping signal.

[0136] In addition, the logic instructions in the above-mentioned memory 530 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when it is sold or used as an independent product. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc. Various media that can store program codes.

[0137] On the other hand, the present invention also provides a computer program product, which includes a computer program. The computer program can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the capture method of the two-stage search for spread-hopping signals provided by the above methods.

[0138] On the other hand, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which is implemented when the computer program is executed by a processor to execute the acquisition method of the two-stage search for spread frequency hopping signals provided by the above methods.

[0139] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0140] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0141] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A two-stage search acquisition method for a spread frequency hopping signal, characterized in that: include: receiving a frequency-hopping spread signal, and performing down-conversion processing on the frequency-hopping spread signal to obtain a processed signal; Based on a first preset search number, performing a first level Doppler search on the processed signal to obtain a first search signal; Despreading the first search signal to obtain a despread signal; Performing intra-hop coherent accumulation on the despread signal to obtain a first accumulated signal; Based on a second preset search number, performing a second level Doppler search on the first accumulated signal to obtain a second search signal; wherein the second preset search number is a ratio of a preset number to the first preset search number, and the preset number is greater than the first preset search number; performing inter-hop phase compensation on the second search signal to obtain a compensated signal; Performing inter-hop coherent accumulation on the compensation signal to obtain a second accumulated signal; determining a peak value of the second accumulated signal; Comparing the magnitude relationship between the peak value and a preset threshold value, and determining a capture result of the spread hopping frequency signal based on the magnitude relationship; The step of despreading the first search signal to obtain a despread signal includes: performing correlation processing on the first search signal using a predefined spread spectrum code; determining a frequency hopping pattern in a current frequency hopping period in the first search signal based on the spreading code; Applying a frequency hopping pattern to the first search signal to perform frequency hopping compensation based on the frequency hopping pattern; Despreading the first search signal after frequency hopping compensation to obtain a despread signal; The threshold value is set in the following way: Setting a threshold value according to characteristics of the spread frequency hopping signal and / or noise; The step of setting the threshold value according to the characteristics of the spread frequency hopping signal and / or the noise includes: If it is detected that the noise level of the spread frequency hopping signal increases, or if no valid signal peak of the spread frequency hopping signal is detected within a preset time period, the threshold value is increased; If the characteristics of the spread frequency hopping signal indicate that the signal strength exceeds a preset strength, or if a signal peak value is continuously detected within a preset time period, the threshold value is lowered.

2. The acquisition method of the two-stage search for spread frequency hopping signals according to claim 1, characterized in that: Before despreading the first search signal to obtain a despread signal, the method further includes: The data integration of the first search signal is down-speeded to 2 times the code rate.

3. The acquisition method of the two-stage search for spread frequency hopping signals according to claim 1, characterized in that: The intra-hop coherent accumulation is to accumulate the signals within the same frequency hopping period; The inter-hop coherent accumulation is to accumulate signals within multiple frequency hopping periods.

4. The acquisition method of the two-stage search for spread frequency hopping signals according to claim 1, characterized in that: Also includes: When performing a first-level Doppler search on the processed signal, determining a conversion relationship between carrier Doppler and code Doppler; Based on the conversion relationship, the code chip slide is controlled not to exceed 0.25 code chip period.

5. The acquisition method of the two-stage search for spread frequency hopping signals according to claim 1, characterized in that: The step of determining the capture result of the spread frequency hopping signal based on the magnitude relationship includes: When the magnitude relationship is such that the peak value exceeds the threshold value, it is confirmed that the spread frequency hopping signal is captured successfully; When the magnitude relationship is that the peak value is lower than the threshold, it is confirmed that the spread hopping signal is not captured successfully, and the process returns to the step of performing a first-level Doppler search on the processed signal based on the first preset search times to obtain a first search signal.

6. The acquisition method of the two-stage search for spread frequency hopping signals according to claim 1, characterized in that: After receiving the spread frequency hopping signal, the method may further include: The received spread frequency hopping signal is buffered.

7. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the program, the two-stage search acquisition method for spread frequency hopping signals as described in any one of claims 1 to 6 is implemented.

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