Satellite mobile communication system multi-broadcast frequency point parallel search method and device

Abstract

The invention discloses a satellite mobile communication system multi-broadcast frequency point parallel search method and device, and the method comprises the steps: obtaining a satellite digital intermediate frequency signal containing a plurality of target frequency bands, carrying out the digital down-conversion processing of the intermediate frequency signal through employing multiple channels, obtaining a baseband signal corresponding to each target frequency band, and transmitting the baseband signal to a receiver; performing cross-correlation operation on the baseband signal after downsampling and filtering processing and a local broadcast signal; and performing frequency domain transformation on a cross-correlation operation result, determining the maximum amplitude and the signal-to-noise ratio in the frequency domain data of each channel, screening the effectiveness of each channel according to the signal-to-noise ratio, and determining the position of the satellite by taking the beam direction corresponding to the maximum amplitude in the effective channel as the incoming wave direction of the broadcast signal. The real-time performance of signal searching in the multi-frequency-point environment is improved, the high signal detection capacity and anti-interference performance are shown in the complex electromagnetic environment, and the method has the advantages of being small in resource consumption, high in operation speed, stable in searching result and good in universality.

Description

Technical Field

[0001] This invention relates to the field of signal search in satellite mobile communication systems, and more specifically to a method and apparatus for parallel search of multiple broadcast frequencies in a satellite mobile communication system. Background Technology

[0002] Traditional satellite broadcast signal search methods rely on field strength measurement, determining the satellite's position by searching for the broadcast signal strength in the airspace where the satellite terminal is located. Field strength measurement generally includes two methods: one involves down-converting the satellite broadcast signal to tens or hundreds of kHz using a double-conversion scheme, then detecting the signal with a logarithmic detector to obtain a voltage value corresponding to the signal strength, and determining the satellite's position based on the magnitude of the voltage value obtained; the other method involves directly sampling the radio frequency analog signal, calculating the signal amplitude in the frequency domain, and identifying the direction of the maximum amplitude as the direction of the satellite signal's arrival. The disadvantage of traditional field strength measurement methods is their weak anti-interference capability. If there are interference signals of similar frequencies in the surrounding environment, such as Wideband Code Division Multiple Access (WCDMA) public network communication signals, it becomes difficult to determine the actual direction of the satellite signal's arrival. Furthermore, traditional broadcast search schemes use a serial frequency point search method, which significantly limits the search speed when there are too many signal frequencies.

[0003] Therefore, there is a need to provide a parallel search method for multiple broadcast frequencies in satellite mobile communication systems to address the shortcomings of traditional satellite broadcast search technology, such as weak anti-interference capability and slow satellite search speed. Summary of the Invention

[0004] In view of this, the present invention provides a method and apparatus for parallel search of multiple broadcast frequencies in a satellite mobile communication system, in order to solve the technical problems of weak anti-interference capability and slow satellite search speed of traditional satellite broadcast search technology.

[0005] In a first aspect, the present invention provides a parallel search method for multiple broadcast frequencies in a satellite mobile communication system, comprising: The control antenna beam scans within a predetermined airspace, traversing multiple beam directions, and acquiring satellite digital intermediate frequency signals containing multiple target frequency bands under each beam direction; According to the preset frequency configuration, the satellite digital intermediate frequency signal is digitally down-converted using multiple channels to obtain the baseband signal corresponding to each target frequency band; The baseband signals of each channel are downsampled and filtered to obtain the data stream to be detected; The data stream to be detected is cross-correlated with a preset local reference signal, and the result is frequency domain transformed to obtain the frequency domain data of each channel. Determine the maximum amplitude and signal-to-noise ratio in the frequency domain data of each channel to obtain the characteristic parameter set of each channel corresponding to the beam pointing; The system summarizes the characteristic parameter set corresponding to all beam directions traversed during the scanning process, filters the effectiveness of each channel based on the signal-to-noise ratio of the characteristic parameter set, and uses the beam direction corresponding to the largest amplitude in the effective channel as the incoming wave direction of the broadcast signal to determine the satellite's position.

[0006] Furthermore, the satellite digital intermediate frequency signal undergoes digital down-conversion processing, including: A digital local oscillation signal with the same frequency as the intermediate frequency signal is generated by a numerically controlled oscillator. The numerically controlled oscillator calculates the frequency control word based on the intermediate frequency, sampling frequency, and bit width of the phase accumulator, and addresses the lookup table based on the frequency control word to output the local carrier data required for down-conversion.

[0007] Furthermore, addressing in the lookup table based on the frequency control word includes: M high-order bits are truncated from the phase accumulation result of N bits as effective addressing bits, where M <N; The M bits are divided into a first address component and a second address component, and the corresponding first and second storage units are indexed to obtain the first phase data and the second phase data, respectively. The local carrier data is obtained by combining the first phase data and the second phase data through trigonometric function operations.

[0008] Furthermore, the downsampling and filtering process includes: When extracting data according to a preset downsampling rate, the sampling points of multiple consecutive baseband signals within each extraction interval are summed; wherein, the preset downsampling rate satisfies the Nyquist sampling theorem; The summation result is output as the data stream to be detected in the current channel.

[0009] Furthermore, the step of performing a cross-correlation operation between the data stream to be detected and a preset local reference signal includes: A baseband discrete sequence is constructed based on the modulation characteristics of the satellite broadcast signal to obtain a preset local reference signal; The system utilizes dual storage spaces for alternating read / write control. While writing the current data stream to be detected to the first storage space, it reads the data stream cached in the previous time period from the second storage space and periodically switches the read / write states of the first and second storage spaces. A data segment is extracted from the storage space in the reading state by sliding a window, and the cross-correlation value between the data segment and the local reference signal sequence is calculated in real time.

[0010] Furthermore, determining the maximum amplitude and signal-to-noise ratio in the frequency domain data of each channel includes: Within a broadcast signal multiframe period, frequency domain data of a specified number of points are output through Fourier transform operation period, the amplitude of frequency domain data at each point is calculated, and the maximum amplitude value in the frequency domain data is determined. In the frequency domain data, determine the signal energy region consisting of the point corresponding to the maximum amplitude and a predetermined number of surrounding points, and use the total energy in this region as the signal component. The signal energy region is removed from the frequency domain data, and the average energy of the remaining frequency band is used as the noise component. The signal-to-noise ratio of the current channel is determined based on the ratio of the signal component to the noise component.

[0011] Furthermore, the effectiveness of each channel is screened based on the maximum signal-to-noise ratio of the feature parameter set, including: The signal-to-noise ratio (SNR) of each channel is compared with a preset SNR threshold. Channel data with an SNR lower than the preset SNR threshold are discarded, and the remaining channels are considered valid channels.

[0012] Furthermore, the beam pointing to the largest amplitude value in the effective channel is used as the direction of arrival of the broadcast signal to determine the satellite's position, including: The amplitudes of each channel with a signal-to-noise ratio higher than the threshold are sorted to determine the maximum amplitude and its corresponding frequency information; The antenna array pointing vector at the corresponding time of the frequency point information is obtained, and combined with the attitude information of the antenna array carrier at the time, the azimuth information of the broadcast satellite in the coordinate system relative to the carrier is calculated.

[0013] Secondly, the present invention provides a parallel search device for multiple broadcast frequencies in a satellite mobile communication system, comprising: The signal acquisition module controls the antenna beam to scan within a predetermined airspace, traversing multiple beam directions, and acquiring satellite digital intermediate frequency signals containing multiple target frequency bands under each beam direction; The multi-channel processing module is used to perform digital down-conversion processing on the satellite digital intermediate frequency signal using multiple channels according to a preset frequency point configuration, so as to obtain the baseband signal corresponding to each target frequency band. The optimization module is used to downsample and filter the baseband signals of each channel to obtain the data stream to be detected; The correlation analysis module is used to perform cross-correlation calculations between the data stream to be detected and a preset local reference signal, and to perform frequency domain transformation on the calculation results to obtain frequency domain data for each channel. The parameter calculation module is used to determine the maximum amplitude and signal-to-noise ratio in the frequency domain data of each channel, and to obtain the characteristic parameter set of each channel corresponding to the beam pointing. The satellite positioning module is used to summarize the characteristic parameter set corresponding to all beam directions traversed during the scanning process, filter the validity of each channel based on the signal-to-noise ratio of the characteristic parameter set, and take the beam direction corresponding to the largest amplitude in the valid channel as the incoming wave direction of the broadcast signal to determine the satellite's position.

[0014] Thirdly, the present invention also provides a computer-readable storage medium storing a computer program, wherein when the computer program is executed by a processor, it implements the parallel search method for multiple broadcast frequencies of a satellite mobile communication system as described in any of the above technical solutions.

[0015] Compared with existing technologies, the parallel search method and apparatus for multiple broadcast frequencies in satellite mobile communication systems proposed in this invention have the following advantages: (1) The satellite broadcast signal is down-converted to low-intermediate frequency through a single frequency conversion scheme, and then the low-intermediate frequency signal is processed by AD conversion. According to the different broadcast frequency points, different FPGA channels are used to receive ADC data in parallel, which solves the disadvantage of slow satellite search speed in the traditional broadcast search scheme. (2) Based on the calculation formula and frame characteristics of satellite broadcast signals, a local original satellite broadcast baseband signal (chirp signal) is generated. The local baseband signal and the received broadcast baseband signal are cross-correlated. Only signals related to the local reference signal will be correctly demodulated and received. It can resist various interferences and clutters that are not related to the reference signal and has strong anti-interference and clutter suppression capabilities in complex electromagnetic environments. Attached Figure Description

[0016] Figure 1 A flowchart illustrating the parallel search method for multiple broadcast frequencies in a satellite mobile communication system provided by this invention; Figure 2 This is a schematic diagram of the structure of the parallel search device for multiple broadcast frequencies in a satellite mobile communication system provided by the present invention. Detailed Implementation

[0017] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0018] Please see Figure 1 This embodiment provides a parallel search method for multiple broadcast frequencies in a satellite mobile communication system, including: Step S101: Control the antenna beam to scan within a predetermined airspace, traverse multiple beam directions, and acquire satellite digital intermediate frequency signals containing multiple target frequency bands under each beam direction; Step S102: According to the preset frequency configuration, the satellite digital intermediate frequency signal is digitally down-converted using multiple channels to obtain the baseband signal corresponding to each target frequency band; Step S103: Downsample and filter the baseband signal of each channel to obtain the data stream to be detected; Step S104: Perform cross-correlation operation on the data stream to be detected and the preset local reference signal, and perform frequency domain transformation on the operation result to obtain the frequency domain data of each channel; Step S105: Determine the maximum amplitude and signal-to-noise ratio in the frequency domain data of each channel to obtain the characteristic parameter set of each channel corresponding to the beam pointing; Step S106: Summarize the feature parameter sets corresponding to all beam directions traversed during the scanning process, filter the effectiveness of each channel based on the signal-to-noise ratio of the feature parameter sets, and take the beam direction corresponding to the largest amplitude in the effective channel as the incoming wave direction of the broadcast signal to determine the satellite's position.

[0019] The parallel search method for multiple broadcast frequencies in a satellite mobile communication system provided in this embodiment first downconverts the input satellite digital intermediate frequency signal, then downsamples and filters the downconverted data, then cross-correlates it with the local beacon signal, then performs a Fourier transform on the cross-correlated data, then calculates the amplitude and signal-to-noise ratio based on the frequency domain data, and finally determines the satellite's position information based on the amplitude and signal-to-noise ratio.

[0020] In a preferred embodiment, in step S101, the amplitude and phase of the antenna array (TR component) are controlled by the beam control unit at certain intervals and with a certain strategy, so that the receiving direction of the antenna is deflected in space and the upper half-space of the terminal is scanned.

[0021] During each beam pointing dwell period, the FPGA receives the satellite digital intermediate frequency signal input from the AD conversion circuit. Based on the data generation principle of the AD chip, the falling edge of the clock is used to acquire the input signal to obtain I-channel data for subsequent processing. During the same dwell period, the FPGA does not search for only one frequency point, but divides the received broadband signal into multiple parallel channels, each channel independently responsible for a specific broadcast frequency point. In the traditional serial method, the FPGA needs to switch frequencies sequentially and search for each frequency point one by one. The total search time = single frequency point processing time × number of frequency points. However, this solution adopts a parallel multi-channel method: all target frequencies are processed simultaneously, and the search time is approximately the single frequency point processing time, significantly improving the satellite search speed.

[0022] In a preferred embodiment, in step S102, the satellite digital intermediate frequency signal is digitally down-converted to baseband (zero intermediate frequency) through multiple channels according to different frequency points, with one channel corresponding to one broadcast frequency point.

[0023] Digital downconversion is mainly achieved through a numerically controlled oscillator (NCO). A digital local oscillation signal with the same frequency as the intermediate frequency signal is generated by a numerically controlled oscillator. The numerically controlled oscillator calculates the frequency control word based on the intermediate frequency, sampling frequency, and bit width of the phase accumulator, and addresses the lookup table based on the frequency control word to output the local carrier data required for down-conversion.

[0024] Specifically: Assume the intermediate frequency is M and the sampling frequency is f. s If the bit width of the phase accumulator is N, then the formula for calculating the frequency control word NCO is: Since the ROM resources occupied by the lookup table will be very large when the data width N is large, the low bits of NCO are discarded and only the high bits are addressed in order to save resources.

[0025] In some embodiments, the high-order bits can be split into two smaller ROMs for processing. In this case, addressing in the lookup table based on the frequency control word includes: M high-order bits are truncated from the phase accumulation result of N bits as effective addressing bits, where M <N; The M bits are divided into a first address component and a second address component, and the corresponding first and second storage units are indexed to obtain the first phase data and the second phase data, respectively. The local carrier data is obtained by combining the first phase data and the second phase data through trigonometric function operations.

[0026] To reduce hardware resource consumption while ensuring frequency synthesis accuracy, this scheme employs a phase splitting algorithm. The M-bit addressing bits are split into high-order address bits. and low address The sine and cosine components of the corresponding phase are obtained through a pre-stored small-scale trigonometric function table, and based on... and The expansion of the expression is combined by complex multiplication to achieve high-fidelity restoration of the local carrier.

[0027] In a preferred embodiment, in step S103, each channel performs downsampling and filtering on the baseband signal. Downsampling reduces the data transmission rate. Frequency aliasing can occur during downsampling; filters can be used to reduce distortion caused by aliasing, ensuring the Nyquist sampling theorem still holds. In this method, downsampling and low-pass filtering are performed simultaneously. While downsampling satisfies the Nyquist sampling theorem, the data is accumulated according to a certain ratio to obtain the downsampled data. This achieves both downsampling and low-pass filtering. The filter formed by accumulation is also a type of low-pass filter, equivalent to all coefficients being 1, forming an average filter.

[0028] As a specific example, if the highest frequency of the broadcast signal is 16kHz, and the 60MHz sample is downsampled to 38.4kHz (38.4kHz > 16kHz * 2, satisfying the Nyquist sampling theorem), then during downsampling, the data is not extracted individually, but accumulated in a ratio (60000 / 38.4≈1563):1 to form the downsampled data (i.e., 1563 60MHz data points are accumulated to obtain 1 38.4kHz data point), thus realizing the function of a low-pass filter.

[0029] In a preferred embodiment, step S104, which involves performing a cross-correlation operation between the data stream to be detected and a preset local reference signal, includes: A baseband discrete sequence is constructed based on the modulation characteristics of the satellite broadcast signal to obtain a preset local reference signal; The system utilizes dual storage spaces for alternating read / write control. While writing the current data stream to be detected to the first storage space, it reads the data stream cached in the previous time period from the second storage space and periodically switches the read / write states of the first and second storage spaces. A data segment is extracted from the storage space in the reading state by sliding a window, and the cross-correlation value between the data segment and the local reference signal sequence is calculated in real time.

[0030] As a specific implementation, the downsampled and filtered satellite broadcast signal baseband data and the local broadcast signal baseband data are cross-correlated. The local broadcast signal baseband data is generated using MATLAB simulation software. The satellite broadcast signal baseband data is processed in real-time using a ping-pong operation, and a segment of the local broadcast signal baseband data is selected for cross-correlation based on the length of the ping-pong processing time window.

[0031] In a specific application scenario, for the chirp broadcast signal transmitted by the Tiantong-1 satellite system, the mathematical expression of chirp is fixed. The ideal waveform of the signal is generated in advance in MATLAB according to the standard protocol of the satellite, and then discretized. The discretized digital file is stored through FPGA. When cross-correlation calculation is required, FPGA can directly read this fixed string of numbers from ROM.

[0032] After cross-correlation between the chirp signal and the local chirp signal, a very obvious peak value will appear in the frequency domain. The direction of arrival can be determined based on this peak value. (If there is no chirp signal in the received signal, there will be no obvious peak value in the frequency domain after cross-correlation between the received signal and the local chirp signal, and it will be at the same level as the noise.)

[0033] A data segment is extracted from the storage space in the reading state using a sliding window, and the cross-correlation value between the data segment and the local reference signal sequence is calculated in real time. Specifically: The data segment is captured using a sliding window of length 32. Multiply each point in the window by the corresponding point of the local reference signal; The window moves backward by 32 sampling points, and the above process is repeated to traverse all received data.

[0034] The points within the window are multiplied one-to-one with the corresponding number of points in the local reference signal, and then the results are subjected to Fourier transforms.

[0035] Furthermore, the IP core is directly invoked to perform a Fourier transform on the cross-correlation results, with the FFT point count set to 256, to obtain the frequency domain data for each channel.

[0036] In a preferred embodiment, in step S104, 256 frequency domain data points are output in each operation cycle during the Fourier transform process. The amplitude of these 256 frequency domain data points is calculated, and the maximum value is found from these 256 amplitude values. Based on the characteristics of the Tiantong-1 broadcast signal frame, multiple linear frequency modulated signals are broadcast at certain time slot intervals within a broadcast signal multiframe cycle. The amplitude received by all channels within a broadcast signal cycle is calculated, and the maximum amplitude received by each channel is found.

[0037] Furthermore, the signal-to-noise ratio (SNR) is calculated based on the amplitude. The SNR for all channels is calculated using the following formula: In the formula: k represents the frequency domain subscript, x(k) 2 This represents the frequency domain amplitude, where m is the index of the maximum frequency domain amplitude, and N represents the number of frequency domain data.

[0038] Similar to the amplitude calculation mentioned above, multiple effective signal-to-noise ratios are generated within a broadcast signal period. The signal-to-noise ratio of the received signal for each channel within a broadcast signal period is calculated.

[0039] In some embodiments, after the FPGA completes the calculation of one broadcast signal cycle, it obtains the characteristic parameter set of each channel, which needs to be passed to the beam control unit for subsequent processing. In terms of hardware design, the data is transmitted from the FPGA to the beam control unit through a serial port. Therefore, the data on the FPGA side needs to be converted into a bit stream, and then the data is transmitted to the beam control unit one by one through the serial port at a certain baud rate to enter the next beam pointing characteristic set calculation process.

[0040] In a preferred embodiment, step S106 involves filtering the effectiveness of each channel based on the maximum signal-to-noise ratio of the feature parameter set, including: The signal-to-noise ratio (SNR) of each channel is compared with a preset SNR threshold. Channel data with an SNR lower than the preset SNR threshold are discarded, and the remaining channels are considered valid channels.

[0041] The step of determining the satellite's position by pointing the beam corresponding to the largest amplitude value in the effective channel as the direction of arrival of the broadcast signal includes: The amplitudes of each channel with a signal-to-noise ratio higher than the threshold are sorted to determine the maximum amplitude and its corresponding frequency information; The antenna array pointing vector at the corresponding time of the frequency point information is obtained, and combined with the attitude information of the antenna array carrier at the time, the azimuth information of the broadcast satellite in the coordinate system relative to the carrier is calculated.

[0042] In some embodiments, the beam control unit adjusts the antenna pointing at certain angular intervals, obtains the maximum signal-to-noise ratio and the maximum amplitude from the FPGA at each pointing direction, uses the signal-to-noise ratio as the basis for determining whether a broadcast signal is present, determines the direction of arrival of the broadcast signal based on the antenna pointing at the maximum amplitude, thereby determining the satellite's azimuth, and simultaneously sends the aforementioned determined broadcast frequency information to the baseband module, thus ending one search process.

[0043] like Figure 2 The present invention also provides a parallel search device 200 for multiple broadcast frequencies in a satellite mobile communication system, comprising: The signal acquisition module 201 controls the antenna beam to scan within a predetermined airspace, traversing multiple beam directions, and acquiring satellite digital intermediate frequency signals containing multiple target frequency bands under each beam direction; The multi-channel processing module 202 is used to perform digital down-conversion processing on the satellite digital intermediate frequency signal using multiple channels according to a preset frequency point configuration, so as to obtain a baseband signal corresponding to each target frequency band. The optimization module 203 is used to downsample and filter the baseband signals of each channel to obtain the data stream to be detected; The correlation analysis module 204 is used to perform cross-correlation operation on the data stream to be detected and a preset local reference signal, and to perform frequency domain transformation on the operation result to obtain frequency domain data of each channel; The parameter calculation module 205 is used to determine the maximum amplitude and signal-to-noise ratio in the frequency domain data of each channel, and to obtain the characteristic parameter set of each channel corresponding to the beam pointing. The satellite positioning module 206 is used to summarize the feature parameter set corresponding to all beam directions traversed during the scanning process, filter the validity of each channel according to the signal-to-noise ratio of the feature parameter set, and take the beam direction corresponding to the largest amplitude in the valid channel as the incoming wave direction of the broadcast signal to determine the satellite's position.

[0044] This embodiment also provides a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, it implements the parallel search method for multiple broadcast frequencies in a satellite mobile communication system as described in any of the above technical solutions.

[0045] The computer-readable storage medium and computing device provided in the above embodiments of the present invention can be implemented with reference to the content specifically described in the present invention for implementing the parallel search method for multiple broadcast frequencies of a satellite mobile communication system as described above, and have similar beneficial effects as the parallel search method for multiple broadcast frequencies of a satellite mobile communication system as described above, which will not be repeated here.

[0046] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for parallel search of multiple broadcast frequencies in a satellite mobile communication system, characterized in that, include: The control antenna beam scans within a predetermined airspace, traversing multiple beam directions, and acquiring satellite digital intermediate frequency signals containing multiple target frequency bands under each beam direction; According to the preset frequency configuration, the satellite digital intermediate frequency signal is digitally down-converted using multiple channels to obtain the baseband signal corresponding to each target frequency band; The baseband signals of each channel are downsampled and filtered to obtain the data stream to be detected; The data stream to be detected is cross-correlated with a preset local reference signal, and the result is frequency domain transformed to obtain the frequency domain data of each channel. Determine the maximum amplitude and signal-to-noise ratio in the frequency domain data of each channel to obtain the characteristic parameter set of each channel corresponding to the beam pointing; The system summarizes the characteristic parameter set corresponding to all beam directions traversed during the scanning process, filters the effectiveness of each channel based on the signal-to-noise ratio of the characteristic parameter set, and uses the beam direction corresponding to the largest amplitude in the effective channel as the incoming wave direction of the broadcast signal to determine the satellite's position.

2. The method according to claim 1, characterized in that, The digital down-conversion processing of the satellite digital intermediate frequency signal includes: A digital local oscillation signal with the same frequency as the intermediate frequency signal is generated by a numerically controlled oscillator. The numerically controlled oscillator calculates the frequency control word based on the intermediate frequency, sampling frequency, and bit width of the phase accumulator, and addresses the lookup table based on the frequency control word to output the local carrier data required for down-conversion.

3. The method according to claim 2, characterized in that, Addressing in the lookup table based on the frequency control word includes: M high-order bits are truncated from the phase accumulation result of N bits as effective addressing bits, where M <N; The M bits are divided into a first address component and a second address component, and the corresponding first and second storage units are indexed to obtain the first phase data and the second phase data, respectively. The local carrier data is obtained by combining the first phase data and the second phase data through trigonometric function operations.

4. The method according to claim 1, characterized in that, The downsampling and filtering process includes: When extracting data according to a preset downsampling rate, the sampling points of multiple consecutive baseband signals within each extraction interval are summed; wherein, the preset downsampling rate satisfies the Nyquist sampling theorem; The summation result is output as the data stream to be detected in the current channel.

5. The method according to claim 1, characterized in that, The step of performing cross-correlation calculation between the data stream to be detected and a preset local reference signal includes: A baseband discrete sequence is constructed based on the modulation characteristics of the satellite broadcast signal to obtain a preset local reference signal; The system utilizes dual storage spaces for alternating read / write control. While writing the current data stream to be detected to the first storage space, it reads the data stream cached in the previous time period from the second storage space and periodically switches the read / write states of the first and second storage spaces. A data segment is extracted from the storage space in the reading state by sliding a window, and the cross-correlation value between the data segment and the local reference signal sequence is calculated in real time.

6. The method according to claim 1, characterized in that, Determining the maximum amplitude and signal-to-noise ratio in the frequency domain data of each channel includes: Within a broadcast signal multiframe period, frequency domain data of a specified number of points are output through Fourier transform operation period, the amplitude of frequency domain data at each point is calculated, and the maximum amplitude value in the frequency domain data is determined. In the frequency domain data, determine the signal energy region consisting of the point corresponding to the maximum amplitude and a predetermined number of surrounding points, and use the total energy in this region as the signal component. The signal energy region is removed from the frequency domain data, and the average energy of the remaining frequency band is used as the noise component. The signal-to-noise ratio of the current channel is determined based on the ratio of the signal component to the noise component.

7. The method according to claim 1, characterized in that, The effectiveness of each channel is screened based on the maximum signal-to-noise ratio of the feature parameter set, including: The signal-to-noise ratio (SNR) of each channel is compared with a preset SNR threshold. Channel data with an SNR lower than the preset SNR threshold are discarded, and the remaining channels are considered valid channels.

8. The method according to claim 1, characterized in that, The beam pointing to the largest amplitude in the effective channel is used as the direction of arrival of the broadcast signal to determine the satellite's position, including: The amplitudes of each channel with a signal-to-noise ratio higher than the threshold are sorted to determine the maximum amplitude and its corresponding frequency information; The antenna array pointing vector at the corresponding time of the frequency point information is obtained, and combined with the attitude information of the antenna array carrier at the time, the azimuth information of the broadcast satellite in the coordinate system relative to the carrier is calculated.

9. A parallel search device for multiple broadcast frequencies in a satellite mobile communication system, characterized in that, include: The signal acquisition module is used to control the antenna beam to scan within a predetermined airspace, traverse multiple beam directions, and acquire satellite digital intermediate frequency signals containing multiple target frequency bands under each beam direction; The multi-channel processing module is used to perform digital down-conversion processing on the satellite digital intermediate frequency signal using multiple channels according to a preset frequency point configuration, so as to obtain the baseband signal corresponding to each target frequency band. The optimization module is used to downsample and filter the baseband signals of each channel to obtain the data stream to be detected; The correlation analysis module is used to perform cross-correlation calculations between the data stream to be detected and a preset local reference signal, and to perform frequency domain transformation on the calculation results to obtain frequency domain data for each channel. The parameter calculation module is used to determine the maximum amplitude and signal-to-noise ratio in the frequency domain data of each channel, and to obtain the characteristic parameter set of each channel corresponding to the beam pointing. The satellite positioning module is used to summarize the characteristic parameter set corresponding to all beam directions traversed during the scanning process, filter the validity of each channel based on the signal-to-noise ratio of the characteristic parameter set, and take the beam direction corresponding to the largest amplitude in the valid channel as the incoming wave direction of the broadcast signal to determine the satellite's position.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, which, when executed by a processor, implements the parallel search method for multiple broadcast frequencies in a satellite mobile communication system as described in any one of claims 1-8.

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