CN113452405B - Signal processing method and device of satellite-borne receiver, electronic equipment and storage medium - Google Patents
Signal processing method and device of satellite-borne receiver, electronic equipment and storage medium Download PDFInfo
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- H04B1/707—Spread spectrum techniques using direct sequence modulation
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- H04B1/7087—Carrier synchronisation aspects
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Abstract
The application provides a signal processing method and device of a satellite-borne receiver, electronic equipment and a storage medium. The method comprises the following steps: capturing a spread spectrum signal transmitted by a user; estimating and roughly compensating frequency offset and local code phase offset of the spread spectrum signal according to a pilot frequency band of the spread spectrum signal, tracking the code phase offset of the spread spectrum signal after rough compensation, and finely adjusting the local code phase; after the spread spectrum signal is tracked stably, dividing the service segment of the spread spectrum signal sent by each user into a plurality of sub-service segments for caching, and demodulating the cached sub-service segment data in sequence; determining the communication rate of the user according to the user transmission service indicated by the service segment of the user; dividing the data segment of the user with the communication rate deviation value within the preset threshold value range into a plurality of sub-data segments for caching, and demodulating the cached sub-service segment data in sequence. The method and the device can realize low-delay processing of different communication service signals, are suitable for multi-rate signal demodulation of different services, and are low in complexity.
Description
Technical Field
The present application relates to the field of satellite communications technologies, and in particular, to a method and an apparatus for processing a signal of a satellite-borne receiver, an electronic device, and a storage medium.
Background
Low earth orbit satellite communication systems are one of the more and more widely used communication systems in recent years. Compared with high and medium orbit satellites, the low orbit satellite communication system has shorter transmission distance than other communication systems, thereby not only reducing the transmitter power of the ground terminal, but also ensuring the low time delay of information transmission.
Different satellite services correspond to different information rates. Generally, the transmission rate required for the message is low, and the transmission of voice, image and video information often requires a high transmission rate to ensure low latency of the information. However, the conventional low-earth orbit satellite communication system only provides a single service, and cannot realize low-delay processing of signals with multiple services and different rates. In addition, because the volume, the weight and the power consumption of the low-earth-orbit satellite communication load need to be strictly controlled, on-satellite operation resources, storage resources and energy supply are severely limited, and the off-line demodulation algorithm adopted in the prior art not only occupies a large amount of storage resources and increases the processing time delay, but also has low frequency offset estimation precision performance, and loses the remarkable advantages of low time delay and high throughput of a low-earth-orbit satellite communication system.
Disclosure of Invention
Due to the above problems of the existing methods, embodiments of the present application provide a signal processing method and apparatus for a satellite-borne receiver, an electronic device, and a storage medium.
Specifically, the embodiment of the present application provides the following technical solutions:
in a first aspect, an embodiment of the present application provides a signal processing method for a satellite-borne receiver, including:
capturing a spread spectrum signal transmitted by a user;
estimating and roughly compensating frequency offset and local code phase offset of the spread spectrum signal according to the pilot frequency band of the spread spectrum signal, continuously tracking the code phase offset of the spread spectrum signal after rough compensation in a preset search range, and finely adjusting the local code phase so as to realize fine synchronization of the code phase of the received spread spectrum signal and the local code phase;
after the spread spectrum signal is tracked stably, dividing the service segment of the spread spectrum signal sent by each user into a plurality of sub-service segments for caching, and demodulating the cached sub-service segment data in sequence;
after the data demodulation of the service segment of the user is finished, determining the communication rate of the user according to the user transmission service indicated by the service segment of the user;
dividing the data segment of the user with the communication rate deviation value within the preset threshold value range into a plurality of sub-data segments for caching, and demodulating the cached sub-data segments in sequence.
Optionally, the acquiring the spread spectrum signal sent by the user includes:
and performing full coherent acquisition on spread spectrum signals sent by a user in a plurality of frequency offset channels based on a serial-parallel combined search mode.
Optionally, demodulating the cached sub-service segment data, and demodulating the cached sub-service segment data includes:
and demodulating the sub-service segment data and the sub-service segment data cached by the user by adopting a mode of searching the frequency offset and the phase of the user by a local template.
Optionally, the spread spectrum signal is sent after performing frequency offset and code phase offset pre-compensation according to the read ephemeris information by the user equipment.
Optionally, the sequentially demodulating the cached sub-service segment data includes:
and sequentially demodulating the sub-service segment data of each user according to the sequence of the current sub-service segment cache by the user.
Optionally, the sequentially demodulating the cached sub-data segment data includes:
and sequentially demodulating the sub-data segment data of each user according to the sequence of the current sub-data segment cache by the user.
In a second aspect, an embodiment of the present application provides a signal processing apparatus of a satellite-borne receiver, including:
the acquisition module is used for acquiring a spread spectrum signal sent by a user;
the first processing module is used for estimating and roughly compensating frequency offset and local code phase offset of the spread spectrum signal according to the pilot frequency band of the spread spectrum signal, continuously tracking the code phase offset of the spread spectrum signal after rough compensation in a preset search range, and finely adjusting the local code phase so as to realize fine synchronization of the code phase of the received spread spectrum signal and the local code phase;
the second processing module is used for dividing the service segment of the spread spectrum signal sent by each user into a plurality of sub-service segments for caching after the spread spectrum signal is tracked and stabilized, and demodulating the cached sub-service segment data in sequence;
the third processing module is used for determining the communication rate of the user according to the user transmission service indicated by the service segment of the user after the demodulation of the service segment data of the user is finished;
and the fourth processing module is used for dividing the data segment of the user with the communication rate deviation value within the preset threshold range into a plurality of sub-data segments for caching, and demodulating the cached sub-data segments in sequence.
In a third aspect, an embodiment of the present application further provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, where the processor implements the steps of the signal processing method of the satellite receiver according to the first aspect when executing the program.
In a fourth aspect, the present application further provides a non-transitory computer-readable storage medium, on which a computer program is stored, where the computer program, when executed by a processor, implements the steps of the signal processing method of the satellite based receiver according to the first aspect.
In a fifth aspect, the present application further provides a computer program product, which includes a computer program, and when the computer program is executed by a processor, the steps of the signal processing method of the satellite-borne receiver according to the first aspect described above are implemented.
According to the technical scheme, in the embodiment of the application, in the capturing stage: capturing a spread spectrum signal transmitted by a user; in the tracking phase: estimating and roughly compensating frequency offset and local code phase offset of the spread spectrum signal according to the pilot frequency band of the spread spectrum signal, continuously tracking the code phase offset of the spread spectrum signal after rough compensation in a preset search range, and finely adjusting the local code phase so as to realize fine synchronization of the code phase of the received spread spectrum signal and the local code phase; in the demodulation stage: dividing the service segment of the spread spectrum signal sent by each user into a plurality of sub-service segments for caching, and demodulating the cached sub-service segment data in sequence; after the data demodulation of the service segment of the user is finished, determining the communication rate of the user according to the user transmission service indicated by the service segment of the user; dividing the data segment of the user with the communication rate deviation value within the preset threshold value range into a plurality of sub-data segments for caching, and demodulating the cached sub-data segments in sequence. Therefore, the embodiment of the application can realize low-delay processing of signals with different services and different rates. Meanwhile, the embodiment of the application has the characteristic of low complexity, so that the situation that the resource and the power consumption of the satellite communication receiver are limited is met.
Drawings
Fig. 1 is a flowchart illustrating steps of a signal processing method of a satellite-borne receiver according to an embodiment of the present application;
fig. 2 is a schematic structural diagram of a user frame provided in an embodiment of the present application;
fig. 3 is a signal processing flow chart of a satellite-borne receiver provided by an embodiment of the present application;
fig. 4 is a schematic diagram of acquiring a spread spectrum signal provided by an embodiment of the present application;
FIG. 5 is a schematic diagram of a demodulation process provided in an embodiment of the present application;
FIG. 6 is a schematic diagram of terminal ephemeris pre-compensation provided by an embodiment of the application;
fig. 7 is a schematic structural diagram of a signal processing apparatus of a satellite-borne receiver according to an embodiment of the present application;
fig. 8 is a schematic structural diagram of an electronic device according to an embodiment of the present application.
Detailed Description
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
It should be noted that the present application is mainly applied to short frame burst communication of a low earth orbit satellite, and the communication system is direct sequence spread spectrum + BPSK, which is suitable for a communication system that needs to process multiple services and multiple communication rates and has severely limited resources. For a low-orbit satellite communication system, a user frame structure needs to be designed for realizing multi-service, low-complexity and multi-rate reception. As shown in fig. 2. The frame structure includes a pilot segment, a service segment, and a data segment. The pilot frequency band and the service band adopt fixed spread spectrum ratio, and the spread spectrum ratio of the data band is adjusted according to the communication rate of the user data. The pilot frequency band does not contain modulation information, and a capturing and tracking module in a receiver algorithm uses the pilot frequency band signal to carry out frequency offset and code phase offset estimation and carries out frequency compensation on the signal. The service segment includes frame start mark, user address, transmission service and communication rate. The data segment is information transmitted by a user. That is, before the user terminal arrives, the demodulation and decoding of the service segment are completed, and the communication rate information is fed back to the despreading module and the demodulation module in time, the despreading module prepares to switch spreading code words and perform data segment despreading, and the demodulation module prepares to switch the data rate and perform data segment demodulation.
Fig. 1 is a flowchart of steps of a signal processing method of a satellite-borne receiver according to an embodiment of the present application, fig. 2 is a schematic diagram of a structure of a user frame according to the embodiment of the present application, fig. 3 is a flowchart of signal processing of the satellite-borne receiver according to the embodiment of the present application, fig. 4 is a schematic diagram of acquiring a spread spectrum signal according to the embodiment of the present application, fig. 5 is a schematic diagram of demodulation processing according to the embodiment of the present application, and fig. 6 is a schematic diagram of terminal ephemeris pre-compensation according to the embodiment of the present application. The signal processing method of the satellite-borne receiver provided by the embodiment of the present application is explained and explained in detail with reference to fig. 1 to 6.
As shown in fig. 1, a method for processing a signal of a satellite-borne receiver provided in an embodiment of the present application includes:
step 101: capturing a spread spectrum signal transmitted by a user;
in this step, a search mode based on serial-parallel combination is used to perform full coherent acquisition on spread spectrum signals sent by users in multiple frequency offset channels. Specifically, the full coherent acquisition of serial and parallel combined channel search is used, the baseband data and the local spread spectrum code are correlated, and the time-frequency two-dimensional plane search is performed. And after the two-dimensional plane search is completed, performing peak detection, judging with a threshold, and if the two-dimensional plane search exceeds the threshold, performing frequency offset coarse compensation and local code phase coarse adjustment on the signal. If the threshold is not exceeded, the signal search is restarted. In the acquisition stage, because of the existence of the parallel processing of multiple acquisition channels, if a plurality of parallel processing channels respectively store the local spreading code sequence, a large amount of hardware storage resources are consumed. Therefore, the method for multiplexing the local spreading code sequences is adopted, namely only 1 local spreading code sequence storage module is used for multiplexing among a plurality of parallel processing channels, so that a large amount of hardware storage resources can be saved. In addition, the method and the device adopt a full coherent acquisition algorithm, the frequency offset searching precision is high, the complexity of a subsequent algorithm module is reduced, and meanwhile, the method and the device can work under a lower signal-to-noise ratio.
It should be noted that, in the full coherent acquisition mode combining serial and parallel and channel search provided in the embodiment of the present application, compared with the conventional method (full parallel search or full serial search), the full coherent acquisition of a direct sequence spread spectrum signal can be completed under the condition of limited time and hardware resources.
Step 102: estimating and roughly compensating frequency offset and local code phase offset of the spread spectrum signal according to the pilot frequency band of the spread spectrum signal, continuously tracking the code phase offset of the spread spectrum signal after rough compensation in a preset search range, and finely adjusting the local code phase so as to realize fine synchronization of the code phase of the received spread spectrum signal and the local code phase;
in this step, optionally, a continuous search with a precision of 0.5Chip and a search range of ± 1Chip is performed on the signal subjected to the coarse frequency offset compensation and the coarse local code phase adjustment to finely adjust the local code phase, so that the code phase of the received signal is synchronized with the local code phase in real time, and the fine synchronization of the local code phase is completed. Specifically, the front and back shifts of the same spreading code are used as different channels locally, and a plurality of channels simultaneously perform related despreading operation with input signals. After accumulating several symbols, making decision, the channel with maximum correlation value is decided as intermediate channel, and using said channel as reference to make regulation so as to implement fine regulation of local code phase and at the same time can implement despreading of signal. After the tracking is started, the frame header synchronization module continuously correlates the despreading result, and after the correlation result is higher than the threshold, namely when the frame is received, the demodulation module starts to work.
Step 103: after the spread spectrum signal is tracked stably, dividing the service segment of the spread spectrum signal sent by each user into a plurality of sub-service segments for caching, and demodulating the cached sub-service segment data in sequence;
in this step, as shown in fig. 5, the service segment of each user is divided into a plurality of sub-service segments and cached. When a user completes the buffer storage of the current sub-service segment, the data of the sub-service segment is demodulated, and the time delay for processing the data is considered to be short, and the processing speed is far faster than the speed for fully storing the buffer data. For a plurality of users, after each user caches a segment of data, the user needs to wait for a certain time to store the next segment of data to be processed. Therefore, during the period, one receiver can be time division multiplexed, and the buffered data of a plurality of users can be demodulated in sequence. It should be noted that the whole process of demodulating the user data needs to be completed before all sub-segment data of the next segment of data of the user is received, so that it is ensured that when the sub-service segment data currently cached by each user is processed, the buffer is not fully stored in the next segment of data, and the current segment of data is processed, thereby avoiding the problem that the demodulation result is caused by data overflow and loss in the demodulation process.
Step 104: after the data demodulation of the service segment of the user is finished, determining the communication rate of the user according to the user transmission service indicated by the service segment of the user;
in this step, after the demodulation of the service segment data of the user is completed, the demodulation of the user data segment is ready to be started, and the data segment rate and the length are different because the transmission service of each user is different. Therefore, data segments for different users are firstly grouped according to the user transmission service indicated by the service segments, users with similar or same rate are grouped, and a demodulation receiver is shared.
Step 105: dividing the data segment of the user with the communication rate deviation value within the preset threshold value range into a plurality of sub-data segments for caching, and demodulating the cached sub-data segments in sequence.
In this step, for users with the same or similar communication rate, the data segment is divided into a plurality of sub-data segments for buffering, and after a user completes the data buffering of one sub-data segment, the sub-data segment is demodulated. It should be noted that the whole process of demodulating the user data needs to be completed before all sub-segment data of the next segment of data of the user is received, so that it is ensured that when sub-segment data currently cached by each user is processed, the buffer is not filled with the next segment of data, and the current segment of data is processed, thereby avoiding the problem that the demodulation result occurs due to data overflow and loss in the demodulation process. The preset threshold range is [250SPS, 256KSPS ], i.e. both the two endpoint values 250SPS and 256KSPS and the intermediate value are included.
It should be noted that, in the conventional demodulation method, all user data needs to be cached offline, and then the offline cached data is compensated according to the frequency offset and the phase estimated by the local search or FFT method, and a large amount of resources are consumed for demodulation of a single user by using the method. For multi-user demodulation, it is not preferable that the conventional method directly adopts a method of adding a demodulation module. According to the demodulation method and the device, for each user, the local template is adopted to carry out parallel search on the frequency deviation and the phase of the user, so that the satellite resources and the time loss are greatly saved, and compared with the traditional demodulation method for searching the frequency deviation and the phase through the local FFT, the demodulation method and the device are higher in precision and less in resource consumption.
According to the technical scheme, in the embodiment of the application, in the capturing stage: capturing a spread spectrum signal transmitted by a user; in the tracking phase: estimating and roughly compensating frequency offset and local code phase offset of the spread spectrum signal according to the pilot frequency band of the spread spectrum signal, continuously tracking the code phase offset of the spread spectrum signal after rough compensation in a preset search range, and finely adjusting the local code phase so as to realize the fine synchronization of the code phase of the received spread spectrum signal and the local code phase; in the demodulation stage: dividing the service segment of the spread spectrum signal sent by each user into a plurality of sub-service segments for caching, and demodulating the cached sub-service segment data in sequence; after the data demodulation of the service segment of the user is finished, determining the communication rate of the user according to the user transmission service indicated by the service segment of the user; dividing the data segment of the user with the same or similar communication speed into a plurality of sub data segments for caching, and demodulating the cached sub service segment data in sequence. Therefore, the embodiment of the application can realize low-delay processing of signals with different services and different rates. Meanwhile, the embodiment of the application has the characteristic of low complexity, so that the situation that the resource and the power consumption of the satellite communication receiver are limited is met.
Based on the content of the foregoing embodiment, in this embodiment, the capturing a spread spectrum signal sent by a user includes:
and performing full coherent acquisition on spread spectrum signals sent by a user in a plurality of frequency offset channels based on a serial-parallel combined search mode.
In this embodiment, it should be noted that, in the acquisition stage, a plurality of frequency offset channels need to be searched, and the existing method is full parallel search or full serial search. In the design, the chip rate is high, the number of frequency offset channels is large, and the time sequence requirement of full serial search is not met; meanwhile, the hardware resource consumption of the full parallel search is not enough due to the limitation of the satellite load hardware resource. Therefore, the full-coherent acquisition method combining serial and parallel and channel search is adopted, parallel search can be inserted into serial search meeting the time sequence requirement, and full-coherent acquisition of direct sequence spread spectrum signals is completed under the condition that time and hardware resources are limited.
Based on the content of the foregoing embodiment, in this embodiment, demodulating the cached sub service segment data and demodulating the cached sub service segment data includes:
and demodulating the sub-service segment data and the sub-service segment data cached by the user by adopting a mode of searching the frequency offset and the phase of the user by a local template.
In this embodiment, it should be noted that the present application can adapt to demodulation of multi-rate signals of different services. Compared with constant-rate demodulation of a traditional algorithm, the method and the device can perform frequency offset phase estimation with different precision on different rates, select the optimal template suitable for the rate to perform frequency offset search, and have the characteristics of high efficiency and low resource consumption.
Based on the content of the foregoing embodiment, in this embodiment, the spread spectrum signal is sent after performing frequency offset and code phase offset pre-compensation based on the ephemeris information read by the user equipment.
In this embodiment, it should be noted that, because the low-earth satellite communication system has a high dynamic characteristic, the doppler range between the satellite and the ground is large, and as the acquisition range increases, the resources consumed by acquisition continuously increase. Therefore, the method and the device read the ephemeris information through the ground terminal, and calculate the relative Doppler effect according to the ephemeris information, so as to pre-compensate the frequency offset and the code offset of the signal. Therefore, the method and the device solve the problems of large search range and huge resource consumption caused by code bias compensation of the traditional acquisition module by means of ephemeris precompensation, and greatly reduce the complexity of the receiver. Therefore, the method and the device can adapt to the scene that the computing resources, the storage resources and the energy supply on the satellite are severely limited. The low-complexity satellite-borne receiver is realized by multiplexing modules, improving an algorithm and pre-compensating ephemeris.
Based on the content of the foregoing embodiment, in this embodiment, the sequentially demodulating the cached sub-service segment data includes:
and sequentially demodulating the sub-service segment data of each user according to the sequence of the current sub-service segment cache by the user.
Based on the content of the foregoing embodiment, in this embodiment, the sequentially demodulating the cached sub-data segments includes:
and sequentially demodulating the sub-data segment data of each user according to the sequence of the current sub-data segment cache by the user.
Based on the content of the above embodiment, in this embodiment, the application supports low-earth-orbit satellite communication services of multiple services such as messages and voice, and is suitable for multiple different data rates. Compared with the traditional single-service communication load satellite, the satellite has comprehensive functions, can select proper communication speed according to service types, and can realize more reasonable power distribution.
Based on the same inventive concept, another embodiment of the present invention provides a signal processing apparatus of a satellite-borne receiver, as shown in fig. 7, the apparatus including:
an acquisition module 1, configured to acquire a spread spectrum signal sent by a user;
the first processing module 2 is configured to perform estimation and coarse compensation of frequency offset and local code phase offset on the spread spectrum signal according to the pilot frequency band of the spread spectrum signal, continuously track the code phase offset of the spread spectrum signal after the coarse compensation within a preset search range, and finely adjust the local code phase, so as to achieve fine synchronization between the code phase of the received spread spectrum signal and the local code phase;
the second processing module 3 is configured to divide the service segment of the spread spectrum signal sent by each user into a plurality of sub-service segments for caching after the spread spectrum signal is tracked and stabilized, and demodulate the cached sub-service segment data in sequence;
the third processing module 4 is used for determining the communication rate of the user according to the user transmission service indicated by the service segment of the user after the demodulation of the service segment data of the user is finished;
and the fourth processing module 5 is configured to divide the data segment of the user with the communication rate deviation value within the preset threshold range into a plurality of sub-data segments for caching, and sequentially demodulate the cached sub-data segments.
In this embodiment, a search mode based on serial-parallel combination is used to perform full coherent acquisition on a spread spectrum signal sent by a user in multiple frequency offset channels. Specifically, the full coherent acquisition of serial and parallel combined channel search is used, the baseband data and the local spread spectrum code are correlated, and the time-frequency two-dimensional plane search is performed. And after the two-dimensional plane search is completed, performing peak detection, judging with a threshold, and if the two-dimensional plane search exceeds the threshold, performing frequency offset coarse compensation and local code phase coarse adjustment on the signal. If the threshold is not exceeded, the signal search is restarted. In the acquisition stage, because of the existence of the parallel processing of multiple acquisition channels, if a plurality of parallel processing channels respectively store the local spreading code sequence, a large amount of hardware storage resources are consumed. Therefore, the method for multiplexing the local spreading code sequences is adopted, namely only 1 local spreading code sequence storage module is used for multiplexing among a plurality of parallel processing channels, so that a large amount of hardware storage resources can be saved.
It should be noted that, in the full coherent acquisition mode combining serial and parallel and channel search provided in the embodiment of the present application, compared with the conventional method (full parallel search or full serial search), the full coherent acquisition of a direct sequence spread spectrum signal can be completed under the condition of limited time and hardware resources.
In this embodiment, optionally, a continuous search with a precision of 0.5Chip and a search range of ± 1Chip is performed on the signal subjected to the coarse frequency offset compensation and the coarse local code phase adjustment to perform code phase offset, and the local code phase is finely adjusted, so that the code phase of the received signal is synchronized with the local code phase in real time, and the fine synchronization of the local code phase is completed. While despreading the signal. After the tracking is started, the frame header synchronization module continuously correlates the despreading result, and after the correlation result is higher than the threshold, namely when the frame is received, the demodulation module starts to work.
In the present embodiment, as shown in fig. 5, the service segment of each user is divided into a plurality of sub-service segments and cached. When a user completes the buffer storage of the current sub-service segment, the data of the sub-service segment is demodulated, and the time delay for processing the data is considered to be short, and the processing speed is far faster than the speed for fully storing the buffer data. For a plurality of users, after each user caches a segment of data, the user needs to wait for a certain time to store the next segment of data to be processed. Therefore, during the period, one receiver can be time division multiplexed, and the buffered data of a plurality of users can be demodulated in sequence. It should be noted that the whole process of demodulating the user data needs to be completed before all sub-segment data of the next segment of data of the user is received, so that it is ensured that when the sub-service segment data currently cached by each user is processed, the buffer is not fully stored in the next segment of data, and the current segment of data is processed, thereby avoiding the problem that the demodulation result is caused by data overflow and loss in the demodulation process.
In this embodiment, after the demodulation of the service segment data of the user is completed, the demodulation of the user data segment is ready to be started, and the data segment rate and the length are different for each user due to the difference of the transmission service. Therefore, data segments for different users are firstly grouped according to the user transmission service indicated by the service segments, users with similar or same rate are grouped, and a demodulation receiver is shared.
In this embodiment, for users with the same or similar communication rate, the data segment of the user is first divided into a plurality of sub-data segments for buffering, and after a user completes the data buffering of one sub-data segment, the user demodulates the data segment. It should be noted that the whole process of demodulating the user data needs to be completed before all sub-segment data of the next segment of data of the user is received, so that it is ensured that when sub-segment data currently cached by each user is processed, the buffer is not filled with the next segment of data, and the current segment of data is processed, thereby avoiding the problem that the demodulation result occurs due to data overflow and loss in the demodulation process.
It should be noted that, in the conventional demodulation method, all user data needs to be cached offline, and then the offline cached data is compensated according to the frequency offset and the phase estimated by the local search or FFT method, and a large amount of resources are consumed for demodulation of a single user by using the method. For multi-user demodulation, it is not preferable that the conventional method directly adopts a method of adding a demodulation module. According to the demodulation method and the device, for each user, the local template is adopted to carry out parallel search on the frequency deviation and the phase of the user, so that the satellite resources and the time loss are greatly saved, and compared with the traditional demodulation method for searching the frequency deviation and the phase through the local FFT, the demodulation method and the device are higher in precision and less in resource consumption.
According to the technical scheme, in the embodiment of the application, in the capturing stage: capturing a spread spectrum signal transmitted by a user; in the tracking phase: estimating and roughly compensating frequency offset and local code phase offset of the spread spectrum signal according to the pilot frequency band of the spread spectrum signal, continuously tracking the code phase offset of the spread spectrum signal after rough compensation in a preset search range, and finely adjusting the local code phase so as to realize fine synchronization of the code phase of the received spread spectrum signal and the local code phase; in the demodulation stage: dividing the service segment of the spread spectrum signal sent by each user into a plurality of sub-service segments for caching, and demodulating the cached sub-service segment data in sequence; after the data demodulation of the service segment of the user is finished, determining the communication rate of the user according to the user transmission service indicated by the service segment of the user; dividing the data segment of the user with the communication rate deviation value within the preset threshold value range into a plurality of sub-data segments for caching, and demodulating the cached sub-data segments in sequence. Therefore, the embodiment of the application can realize low-delay processing of signals with different services and different rates. Meanwhile, the embodiment of the application has the characteristic of low complexity, so that the situation that the resource and the power consumption of the satellite communication receiver are limited is met.
Fig. 8 illustrates a physical structure diagram of an electronic device, and as shown in fig. 8, the electronic device may include: a processor (processor)810, a communication Interface 820, a memory 830 and a communication bus 840, wherein the processor 810, the communication Interface 820 and the memory 830 communicate with each other via the communication bus 840. The processor 810 may invoke logic instructions in the memory 830 to perform a method of signal processing for a satellite based receiver, the method comprising: capturing a spread spectrum signal transmitted by a user; estimating and roughly compensating frequency offset and local code phase offset of the spread spectrum signal according to the pilot frequency band of the spread spectrum signal, continuously tracking the code phase offset of the spread spectrum signal after rough compensation in a preset search range, and finely adjusting the local code phase so as to realize fine synchronization of the code phase of the received spread spectrum signal and the local code phase; after the spread spectrum signal is tracked stably, dividing the service segment of the spread spectrum signal sent by each user into a plurality of sub-service segments for caching, and demodulating the cached sub-service segment data in sequence; after the data demodulation of the service segment of the user is finished, determining the communication rate of the user according to the user transmission service indicated by the service segment of the user; dividing the data segment of the user with the communication rate deviation value within the preset threshold value range into a plurality of sub-data segments for caching, and demodulating the cached sub-data segments in sequence.
In addition, the logic instructions in the memory 830 may be implemented in software functional units and stored in a computer readable storage medium when the logic instructions are sold or used as independent products. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.
In another aspect, the present invention also provides a computer program product, the computer program product including a computer program, the computer program being storable on a non-transitory computer-readable storage medium, wherein when the computer program is executed by a processor, the computer is capable of executing the signal processing method of the satellite receiver provided by the above methods, and the method includes: capturing a spread spectrum signal transmitted by a user; estimating and roughly compensating frequency offset and local code phase offset of the spread spectrum signal according to the pilot frequency band of the spread spectrum signal, continuously tracking the code phase offset of the spread spectrum signal after rough compensation in a preset search range, and finely adjusting the local code phase so as to realize fine synchronization of the code phase of the received spread spectrum signal and the local code phase; after the spread spectrum signal is tracked stably, dividing the service segment of the spread spectrum signal sent by each user into a plurality of sub-service segments for caching, and demodulating the cached sub-service segment data in sequence; after the data demodulation of the service segment of the user is finished, determining the communication rate of the user according to the user transmission service indicated by the service segment of the user; dividing the data segment of the user with the communication rate deviation value within the preset threshold value range into a plurality of sub-data segments for caching, and demodulating the cached sub-data segments in sequence.
In yet another aspect, the present invention also provides a non-transitory computer-readable storage medium having stored thereon a computer program which, when executed by a processor, implements a method of signal processing for an on-board receiver provided by the above methods, the method comprising: capturing a spread spectrum signal transmitted by a user; estimating and roughly compensating frequency offset and local code phase offset of the spread spectrum signal according to the pilot frequency band of the spread spectrum signal, continuously tracking the code phase offset of the spread spectrum signal after rough compensation in a preset search range, and finely adjusting the local code phase so as to realize fine synchronization of the code phase of the received spread spectrum signal and the local code phase; after the spread spectrum signal is tracked stably, dividing the service segment of the spread spectrum signal sent by each user into a plurality of sub-service segments for caching, and demodulating the cached sub-service segment data in sequence; after the data demodulation of the service segment of the user is finished, determining the communication rate of the user according to the user transmission service indicated by the service segment of the user; dividing the data segment of the user with the communication rate deviation value within the preset threshold value range into a plurality of sub-data segments for caching, and demodulating the cached sub-data segments in sequence.
The above-described embodiments of the apparatus are merely illustrative, and the units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.
Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware. With this understanding in mind, the above-described technical solutions may be embodied in the form of a software product, which can be stored in a computer-readable storage medium such as ROM/RAM, magnetic disk, optical disk, etc., and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the methods described in the embodiments or some parts of the embodiments.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (8)
1. A method for processing signals in a satellite-borne receiver, comprising:
capturing a spread spectrum signal transmitted by a user;
estimating and roughly compensating frequency offset and local code phase offset of the spread spectrum signal according to the pilot frequency band of the spread spectrum signal, continuously tracking the code phase offset of the spread spectrum signal after rough compensation in a preset search range, and finely adjusting the local code phase so as to realize fine synchronization of the code phase of the received spread spectrum signal and the local code phase;
after the spread spectrum signal is tracked stably, dividing the service segment of the spread spectrum signal sent by each user into a plurality of sub-service segments for caching, and demodulating the cached sub-service segment data in sequence;
after the data demodulation of the service segment of the user is finished, determining the communication rate of the user according to the user transmission service indicated by the service segment of the user;
dividing the data segment of the user with the communication rate deviation value within the preset threshold range into a plurality of sub-data segments for caching, and demodulating the cached sub-data segment data in sequence;
wherein the acquiring the spread spectrum signal transmitted by the user comprises:
and performing full coherent acquisition on spread spectrum signals sent by a user in a plurality of frequency offset channels based on a serial-parallel combined search mode.
2. The signal processing method of the satellite receiver according to claim 1, wherein demodulating the buffered sub-service segment data and demodulating the buffered sub-service segment data comprises:
and demodulating the sub-service segment data and the sub-service segment data cached by the user by adopting a mode of searching the frequency offset and the phase of the user by a local template.
3. The method as claimed in claim 1, wherein the spread spectrum signal is transmitted after being pre-compensated for frequency offset and code phase offset based on the ephemeris information read by the ue.
4. The signal processing method of the satellite receiver according to claim 1, wherein the sequentially demodulating the buffered sub-service segment data comprises:
and sequentially demodulating the sub-service segment data of each user according to the sequence of the current sub-service segment cache by the user.
5. The method for signal processing of a satellite-borne receiver according to claim 1, wherein the sequentially demodulating the buffered sub-data segments comprises:
and sequentially demodulating the sub-data segment data of each user according to the sequence of the current sub-data segment cache by the user.
6. A signal processing apparatus of a satellite-borne receiver, comprising:
the acquisition module is used for acquiring a spread spectrum signal sent by a user;
the first processing module is used for estimating and roughly compensating frequency offset and local code phase offset of the spread spectrum signal according to the pilot frequency band of the spread spectrum signal, continuously tracking the code phase offset of the spread spectrum signal after rough compensation in a preset search range, and finely adjusting the local code phase so as to realize fine synchronization of the code phase of the received spread spectrum signal and the local code phase;
the second processing module is used for dividing the service segment of the spread spectrum signal sent by each user into a plurality of sub-service segments for caching after the spread spectrum signal is tracked and stabilized, and demodulating the cached sub-service segment data in sequence;
the third processing module is used for determining the communication rate of the user according to the user transmission service indicated by the service segment of the user after the demodulation of the service segment data of the user is finished;
the fourth processing module is used for dividing the data segment of the user with the communication rate deviation value within the preset threshold value range into a plurality of sub-data segments for caching, and demodulating the cached sub-data segment data in sequence;
wherein, the capture module is specifically configured to:
and performing full coherent acquisition on spread spectrum signals sent by a user in a plurality of frequency offset channels based on a serial-parallel combined search mode.
7. An electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, characterized in that the processor, when executing the program, carries out the steps of the signal processing method of the on-board receiver according to any of claims 1 to 5.
8. A non-transitory computer-readable storage medium, on which a computer program is stored, which, when being executed by a processor, carries out the steps of the signal processing method of the on-board receiver according to any one of claims 1 to 5.
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