GNSS weak signal capturing method and device under satellite power enhancement condition
By reconstructing and canceling co-channel multiple access interference caused by satellite power enhancement, the weak signal acquisition capability of GNSS receiver terminals under satellite power enhancement conditions is improved, solving the problem of interference with weak GNSS signals in satellite power enhancement scenarios, and achieving efficient positioning and timing performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-23
- Publication Date
- 2026-04-17
AI Technical Summary
Under conditions of enhanced satellite power, weak GNSS signals are susceptible to interference from multiple access on the same frequency, leading to a decrease in acquisition success rate. Existing technologies cannot effectively solve this problem.
By acquiring the signal processed by the GNSS receiving terminal, the amplitude and phase of co-channel multiple access interference are estimated, the co-channel multiple access interference is reconstructed and canceled, detection statistics are constructed and a time-frequency two-dimensional search is performed, and a threshold decision is made to determine whether the target signal is captured.
It significantly improves the weak signal acquisition capability of GNSS receiver terminals under enhanced satellite power conditions, increases positioning success rate and timing accuracy, and requires no additional hardware to adapt to existing terminals, resulting in low hardware complexity.
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Figure CN121878731A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of satellite navigation technology, and in particular to a method and apparatus for acquiring weak GNSS signals under conditions of enhanced satellite power. Background Technology
[0002] Global Navigation Satellite Systems (GNSS), represented by GPS and BeiDou, are airborne radio navigation systems that provide three-dimensional position and time information to ground, air, and even low- and medium-Earth orbit satellite users. They offer advantages such as wide coverage, high precision, and all-weather capability. As a universal, convenient, and economical navigation and positioning method, GNSS has been widely applied in aircraft, ships, automobiles, smartphones, drones, and various smart wearable devices. However, electromagnetic interference remains a major threat hindering the widespread application of GNSS in key civilian sectors.
[0003] To improve the anti-interference capability of GNSS receivers, anti-interference array antennas can be installed on GNSS receivers. Existing research shows that by installing anti-interference array antennas, the anti-interference capability of GNSS receivers can be improved by more than 60 decibels compared to ordinary antennas, and they can simultaneously combat electromagnetic interference from multiple directions, making it a very effective solution to the electromagnetic interference problem. However, installing anti-interference array antennas significantly increases the size, weight, and power consumption of GNSS receivers, and also greatly increases costs. These drawbacks limit its application scenarios and scope.
[0004] At the system level, power enhancement strategies can be employed to increase the broadcast power of navigation signals on satellites. This method can improve the anti-interference capability of all GNSS receiving terminals within the target area. Currently, GPS third-generation satellites can enhance signal power by 20 decibels through spot beam technology, and BeiDou-3 satellites also possess power enhancement capabilities. Power enhancement capability has become a core functional indicator for navigation satellites and will be further improved in the future.
[0005] While power enhancement can improve the anti-interference capability of GNSS terminals, the strong navigation signals broadcast by power-enhanced satellites (hereinafter referred to as strong GNSS signals) will cause co-channel multiple access interference to the weak navigation signals broadcast by ordinary satellites (i.e., satellites that do not employ power enhancement strategies) (hereinafter referred to as weak GNSS signals), affecting the reception of weak GNSS signals. Existing research shows that when the power enhancement reaches 30 dB or more, the co-channel multiple access interference caused by strong GNSS signals will make it difficult to acquire weak GNSS signals. We know that GNSS terminals need to receive signals from four or more satellites to calculate position and time information, and generally, the more satellites, the higher the positioning and timing accuracy. In satellite power enhancement mode, strong GNSS signals can be acquired and received normally due to their high power, but the success rate of acquiring weak GNSS signals will decrease due to interference from strong GNSS signals at the same frequency. If weak GNSS signals cannot be acquired and received, the GNSS receiving terminal may fail to position or experience deterioration in positioning accuracy due to insufficient received satellite signals. How to achieve the acquisition of weak GNSS signals under satellite power enhancement conditions is a technical challenge in this field. Summary of the Invention
[0006] Therefore, it is necessary to provide a method and apparatus for acquiring weak GNSS signals under satellite power enhancement conditions, which can effectively eliminate co-channel multiple access interference caused by satellite power enhancement and improve the ability to acquire weak GNSS signals, in order to address the above-mentioned technical problems.
[0007] A method for acquiring weak GNSS signals under enhanced satellite power conditions, the method comprising: Acquire the signal to be processed, which is the signal preprocessed by the GNSS receiving terminal; Based on the signal to be processed and the corresponding signal envelope, estimate the amplitude and phase of the co-channel multiple access interference, and reconstruct the co-channel multiple access interference based on the amplitude and phase of the co-channel multiple access interference. The co-frequency multiple access interference obtained from reconstruction is used to cancel the co-frequency multiple access interference in the signal to be processed, resulting in a signal after interference cancellation. A detection statistic is constructed based on the interference-cancelled signal, and a time-frequency two-dimensional search is performed on the detection statistic. Based on the time-frequency two-dimensional search results, a threshold decision is made to determine whether the target signal has been captured, and the parameters of the target signal are estimated when the target signal is captured.
[0008] In one embodiment, the signal to be processed is a complex sequence obtained by amplifying, filtering, orthogonal downconverting, and sampling quantizing the electromagnetic signal received by the GNSS receiving terminal.
[0009] In one embodiment, the amplitude of co-channel multiple access interference is estimated based on the signal envelope of the signal to be processed using the following formula:
[0010] In the above formula, This represents the signal envelope. Represents a positive integer, indicating the data length used to estimate the amplitude of co-channel multiple access interference.
[0011] In one embodiment, the phase of co-channel multiple access interference is estimated based on the signal to be processed using the following formula:
[0012] In the above formula, This indicates the phase take operation.
[0013] In one embodiment, the reconstructed co-channel multiple access interference is represented as:
[0014] In the above formula, , These represent the amplitude and phase of co-channel multiple access interference, respectively.
[0015] In one embodiment, the step of constructing a detection statistic based on the interference-cancelled signal is expressed as:
[0016] In the above formula, For the test statistic, the value is taken from curly braces. The maximum value of the expression in the curly braces. The value of the expression in the expression is determined by frequency. and latency Sure, This refers to the signal after eliminating co-channel multiple access interference. For weak GNSS signals, a pseudo-random code sequence. The length of the relevant integral operation.
[0017] In one embodiment, when performing a time-frequency two-dimensional search on the detection statistic, the time-frequency two-dimensional search result is when the detection statistic reaches its maximum value, as represented by:
[0018] In the above formula, frequency and latency At that time, the detection statistic reached its maximum value.
[0019] In one embodiment, the step of determining whether a target signal has been captured based on a threshold decision using a time-frequency two-dimensional search result, and estimating the parameters of the target signal when it has been captured, includes: A decision threshold is determined based on a preset false alarm probability, and the time-frequency two-dimensional search result is compared with the decision threshold. If the time-frequency two-dimensional search result is greater than the decision threshold, it is determined that the target GNSS weak signal has been successfully captured. At the same time, the frequency and time delay corresponding to the maximum value of the detection statistics during the time-frequency two-dimensional search process are extracted. The frequency is used as the Doppler frequency estimate of the target GNSS weak signal, and the time delay is used as the pseudo-code phase estimate of the target GNSS weak signal. If the detection statistic is not greater than the decision threshold, it is determined that the target GNSS weak signal was not captured.
[0020] This application also provides a GNSS weak signal acquisition device under satellite power enhancement conditions, the device comprising: The signal acquisition module is used to acquire the signal to be processed, which is the signal preprocessed by the GNSS receiving terminal. The co-channel multiple access interference reconstruction module is used to estimate the amplitude and phase of the co-channel multiple access interference based on the signal to be processed and the corresponding signal envelope, and to reconstruct the co-channel multiple access interference based on the amplitude and phase of the co-channel multiple access interference. The interference cancellation module is used to cancel the co-frequency multiple access interference in the signal to be processed using the reconstructed co-frequency multiple access interference, so as to obtain the interference-cancelled signal. A time-frequency two-dimensional search module is used to construct a detection statistic based on the interference-cancelled signal and to perform a time-frequency two-dimensional search on the detection statistic. The target signal acquisition module is used to determine whether a target signal has been acquired based on the time-frequency two-dimensional search results and through threshold decision, and to estimate the parameters of the target signal when it is acquired.
[0021] A computer device includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program to implement the steps in the above-described method for capturing weak GNSS signals under enhanced satellite power conditions.
[0022] A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps in the above-described method for capturing weak GNSS signals under enhanced satellite power conditions.
[0023] The aforementioned GNSS weak signal acquisition method and apparatus under enhanced satellite power conditions acquires the signal to be processed by the GNSS receiving terminal, estimates the amplitude and phase of co-channel multiple access interference based on the signal to be processed and its corresponding signal envelope, reconstructs the co-channel multiple access interference based on the amplitude and phase of the interference, uses the reconstructed co-channel multiple access interference to cancel the interference in the signal to be processed, obtains the interference-cancelled signal, constructs a detection statistic based on the interference-cancelled signal, performs a time-frequency two-dimensional search on the detection statistic, determines whether the target signal has been acquired based on the time-frequency two-dimensional search result through a threshold decision, and estimates the parameters of the target signal when the target signal is acquired.
[0024] This method effectively solves the technical problem of weak signals being overwhelmed by strong interference in power-enhanced scenarios by targeting reconstruction and canceling co-channel multiple access interference generated by satellite power enhancement. It significantly improves the sensitivity and success rate of GNSS receiver terminals in acquiring weak signals. It does not require additional hardware equipment, is compatible with the signal processing flow of existing GNSS receiver terminals, has low hardware complexity, and is easy to promote. At the same time, it can accurately estimate the parameters of the acquired weak signals, providing reliable support for improving the positioning success rate and timing accuracy of GNSS terminals, and achieving compatibility between satellite power enhancement services and weak signal acquisition. Attached Figure Description
[0025] Figure 1 This is a flowchart illustrating a method for acquiring weak GNSS signals under enhanced satellite power conditions in one embodiment. Figure 2 This is a schematic diagram illustrating the effect of co-frequency multiple access interference cancellation before and after the satellite power enhancement condition obtained using this method in an experiment. Figure 3 This is a schematic diagram of the correlation peak acquisition results of weak GNSS signals under satellite power enhancement conditions obtained using this method in an experiment. Figure 4 This is a structural block diagram of a GNSS weak signal acquisition device under satellite power enhancement conditions in one embodiment; Figure 5 This is an internal structural diagram of a computer device in one embodiment. Detailed Implementation
[0026] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.
[0027] In view of the shortcomings of existing technologies, such as the tendency of strong signals to cause co-channel multiple access interference in satellite power enhancement scenarios, leading to the submergence and difficulty in capturing weak GNSS signals, and the poor adaptability of existing anti-interference methods, which cannot simultaneously provide power enhancement services and weak signal acquisition, this application addresses these shortcomings. Figure 1 As shown, a method for acquiring weak GNSS signals under enhanced satellite power conditions is provided, which specifically includes the following steps: Step S100: Obtain the signal to be processed, which is the signal preprocessed by the GNSS receiving terminal.
[0028] Step S110: Estimate the amplitude and phase of the co-channel multiple access interference based on the signal to be processed and the corresponding signal envelope, and reconstruct the co-channel multiple access interference based on the amplitude and phase of the co-channel multiple access interference.
[0029] Step S120: Using the reconstructed co-frequency multiple access interference, the co-frequency multiple access interference in the signal to be processed is cancelled to obtain the interference-cancelled signal.
[0030] Step S130: Construct a detection statistic based on the signal after interference cancellation, and perform a time-frequency two-dimensional search on the detection statistic.
[0031] Step S140: Based on the time-frequency two-dimensional search results, determine whether the target signal has been captured by threshold decision, and estimate the parameters of the target signal when the target signal is captured.
[0032] Unlike traditional methods, this method employs co-channel multiple access interference reconstruction and cancellation techniques to reconstruct and eliminate strong GNSS signals broadcast by power-enhanced satellites, i.e., co-channel multiple access interference, which greatly improves the ability of GNSS receivers to acquire weak GNSS signals under satellite power enhancement conditions.
[0033] In step S100, the signal to be processed is an electromagnetic signal broadcast by a satellite first received by the GNSS receiving terminal. This signal contains a strong signal broadcast by a power-enhanced satellite, i.e., co-channel multiple access interference, as well as a weak GNSS signal to be acquired. The receiving terminal sequentially amplifies, filters, performs quadrature down-conversion, and samples and quantizes the electromagnetic signal to convert the analog signal into a digital signal, thus obtaining the signal to be processed. This signal to be processed is in the form of a complex sequence, which can accurately characterize the amplitude and phase information of the original signal.
[0034] Specifically, the signal to be processed is represented as ,in It is a sequence of complex numbers. n = 1, 2, … are the time indices of the complex number sequence.
[0035] In step S110, firstly, the signal envelope of the signal to be processed is calculated to highlight the amplitude characteristics of co-channel multiple access interference. Then, based on this signal envelope, the amplitude of the co-channel multiple access interference is accurately estimated through statistical calculations using multiple sets of data. Simultaneously, based on the signal to be processed itself, the phase of the co-channel multiple access interference is obtained through phase taking operations. Finally, combining the estimated interference amplitude and phase, a co-channel multiple access interference signal consistent with the actual interference characteristics is reconstructed using a complex exponential form, laying the foundation for subsequent interference cancellation.
[0036] In this embodiment, the envelope of the signal is represented as:
[0037] In the above formula, Represents the envelope of the signal. This indicates the absolute value operation. Specifically, based on the signal envelope of the signal to be processed, the amplitude of co-channel multiple access interference is estimated using the following formula:
[0038] In the above formula, This represents the signal envelope. Represents a positive integer, indicating the data length used to estimate the amplitude of co-channel multiple access interference.
[0039] Specifically, based on the signal to be processed, the phase of co-channel multiple access interference is estimated using the following formula:
[0040] In the above formula, This indicates the phase take operation.
[0041] Furthermore, after estimating the amplitude and phase of the co-channel multiple access interference, the co-channel multiple access interference can be reconstructed using the following formula:
[0042] In the above formula, , These represent the amplitude and phase of co-channel multiple access interference, respectively.
[0043] In step S120, the reconstructed co-channel multiple access interference is used to cancel the co-channel multiple access interference in the signal to be processed, resulting in a canceled signal. The co-channel multiple access interference signal reconstructed in step S110 is then used in reverse cancellation with the signal to be processed obtained in step S100, i.e., the reconstructed interference signal is subtracted from the signal to be processed, thereby specifically eliminating the co-channel multiple access interference in the signal to be processed, retaining the weak GNSS signal to be captured, and obtaining a canceled signal, thus improving the signal-to-noise ratio of the weak signal.
[0044] Specifically, the following formula is used to eliminate co-channel multiple access interference:
[0045] In the above formula, This is to eliminate the signal after multiple access interference on the same frequency.
[0046] In step S130, a detection statistic is constructed based on the interference-cancelled signal, and a two-dimensional time-frequency search is performed on the detection statistic. First, based on the interference-cancelled signal and combined with the publicly available pseudo-random code sequence of the weak GNSS signal, a detection statistic is constructed. This statistic can effectively characterize the relevant features of the weak signal. Since the weak GNSS signal has Doppler frequency offset and pseudo-code phase offset, a two-dimensional traversal search of the detection statistic in terms of frequency and time delay is required. During the traversal, the detection statistic values under different frequency and time delay combinations are calculated, and the parameter combination corresponding to the maximum value of the statistic is selected.
[0047] In this embodiment, a detection statistic is constructed based on the signal after interference cancellation, and is expressed as:
[0048] In the above formula, For the test statistic, the value is taken from curly braces. The maximum value of the expression in the curly braces. The value of the expression in the expression is determined by frequency. and latency Therefore, the calculation process of the above formula requires the frequency to be determined. and latency Perform a two-dimensional time-frequency search. It is a pseudo-random code sequence for weak GNSS signals, and its parameters are publicly known. The length of the relevant integral operation is a positive integer.
[0049] Furthermore, when performing a time-frequency two-dimensional search on the detection statistics, it is assumed that the curly braces... The expression in , If the maximum value is taken at time, the detection statistic can be expressed as:
[0050] In the above formula, frequency and latency At that time, the detection statistic reached its maximum value.
[0051] In step S140, based on the time-frequency two-dimensional search results, a threshold decision is made to determine whether the target signal has been captured, and the parameters of the target signal are estimated when it is captured. First, a decision threshold is determined according to a preset false alarm probability to ensure the reliability of the decision result. The maximum value of the detection statistics obtained in step S130 (i.e., the time-frequency two-dimensional search results) is compared with this decision threshold. If the statistics are greater than the decision threshold, it is determined that the target GNSS weak signal has been successfully captured. Simultaneously, the frequency and time delay corresponding to the maximum value of the statistics during the search process are extracted and used as the Doppler frequency estimate and pseudo-code phase estimate of the target weak signal, respectively. If the statistics are not greater than the decision threshold, it is determined that the target GNSS weak signal has not been captured.
[0052] It should be noted that the GNSS weak signal acquisition method under satellite power enhancement conditions proposed in this paper is not a simple superposition of existing satellite power enhancement technology, GNSS anti-interference technology and weak signal acquisition technology, nor is it a conventional reuse of existing co-frequency multiple access interference reconstruction and cancellation technology. Rather, it is an exclusive innovative design for the special application scenario of satellite power enhancement, and its technical ideas and implementation path are not obvious to those skilled in the art.
[0053] It should be clarified that co-channel multiple access interference reconstruction and cancellation technology is an existing technology with a foundation in fields such as communications, radar, and satellite navigation. In communications and radar scenarios, this technology requires known signal structure and format, and reconstructs a "clean copy" of the signal by estimating parameters such as time delay and Doppler to achieve cancellation. However, in civilian satellite navigation scenarios, this technology can only be used for civilian signals with publicly available pseudo-random codes, reconstructing and canceling the signal by capturing and tracking strong signals, estimating parameters such as time delay and carrier phase, and cannot be adapted to licensed signals encrypted with pseudo-random codes. Furthermore, in existing technologies, this type of interference cancellation technology has never been applied to the specific scenario of satellite power enhancement, nor has it been used to solve the core technical challenge of strong signal co-channel multiple access interference and weak signal acquisition mutual exclusion in this scenario.
[0054] Current satellite power enhancement strategies focus solely on increasing navigation signal power in specific areas to improve anti-interference capabilities, neglecting the side effects of strong co-channel multiple access interference caused by power enhancement. This results in weak GNSS signals being overwhelmed and difficult to acquire in such scenarios. Existing GNSS anti-interference technologies either rely on multi-antenna arrays (high hardware complexity and poor adaptability) or target common interference types such as broadband noise and deception interference, without designing solutions specifically for strong co-channel multiple access interference generated by satellite power enhancement. Existing weak signal acquisition technologies only optimize thresholds and improve sensitivity, failing to address the problem of suppressing strong interference in satellite power enhancement environments. In summary, existing technologies and conventional applications of existing co-channel multiple access interference reconstruction and cancellation techniques cannot solve the technical challenge of the mutual exclusion between satellite power enhancement and weak GNSS signal acquisition.
[0055] This method addresses the core shortcomings of existing technologies by applying co-frequency multiple access interference reconstruction and cancellation techniques to satellite power enhancement scenarios for the first time. It innovatively modifies and adapts the technology to suit the interference characteristics and technical requirements of this scenario. This method explicitly defines the strong signals broadcast by power-enhanced satellites as co-frequency multiple access interference requiring targeted elimination. It abandons the reliance of traditional co-frequency multiple access interference reconstruction and cancellation techniques on known signal structures and formats (such as communication / radar self-transmission and reception, and publicly available pseudo-random codes for civilian satellite navigation signals). Instead, it innovatively utilizes the constant envelope property of satellite navigation signals (the signal envelope is constant and estimable) to design a complete closed-loop technical path encompassing signal envelope calculation, interference amplitude / phase estimation, interference reconstruction, interference cancellation, time-frequency two-dimensional search, and threshold decision. This technical approach is not a simple application of existing co-frequency multiple access interference reconstruction and cancellation techniques, but rather a unique innovation specifically for satellite power enhancement scenarios. It accurately extracts strong signal interference features through signal envelope calculation, and achieves blind reconstruction and blind cancellation without the need for signal structure / format prediction based on amplitude and phase estimation. This avoids the damage to weak signals caused by traditional broad-spectrum suppression algorithms and solves the technical bottleneck that traditional co-frequency multiple access interference cancellation techniques cannot adapt to satellite navigation licensed signals (pseudo-random code encryption). Furthermore, after targeted interference elimination, it accurately captures GNSS weak signals through time-frequency two-dimensional search and threshold decision, ultimately achieving compatibility between satellite power enhancement services and weak signal acquisition. This fills the technical gap in GNSS weak signal acquisition in satellite power enhancement scenarios, significantly differing from existing technologies and conventional application modes of existing interference cancellation techniques, and fully demonstrating outstanding substantive features and significant technological progress.
[0056] Furthermore, the effectiveness of this method was demonstrated through experiments. For example... Figure 2 As shown, this is a diagram illustrating the effect of co-channel multiple access interference cancellation before and after using this method under enhanced satellite power conditions. Figure 3 The figure shown is a correlation peak result of GNSS weak signal acquisition under satellite power enhancement conditions obtained by this method.
[0057] In the experiment, the satellite signal was the BeiDou B3I signal, with a center frequency of 1268.52MHz and a pseudocode rate of 10.23Mcps. Satellite 1 did not undergo power enhancement, and its signal power at ground was the nominal value of -163dBW. Satellite 2 underwent power enhancement by 30 dB, resulting in a signal power at ground of -133dBW. The data length K used to estimate the amplitude of co-channel multiple access interference was 20000, and the length N of the correlation integration operation was also 20000. From... Figure 2 As can be seen, after the co-channel multiple access interference is cancelled, the power spectrum of the signal is close to flat, similar to the power spectrum of the noise. The power spectrum amplitude before and after cancellation decreased by an average of 30 dB, indicating that the co-channel multiple access interference was fully cancelled. Figure 3(a) shows the result of acquiring satellite 1 (i.e. weak GNSS signal) using the traditional method. There is no obvious correlation peak in the figure, indicating that the signal acquisition failed. Figure 3 (b) shows the result of capturing satellite 1 using the method of the present invention. There is a very obvious correlation peak in the figure, indicating that the signal was successfully captured. Figure 2 and Figure 3 The results show that this method can significantly improve the ability of GNSS receivers to acquire weak GNSS signals under enhanced satellite power conditions.
[0058] In the above-mentioned method for acquiring weak GNSS signals under enhanced satellite power conditions, the co-frequency multiple access interference reconstruction and cancellation technology reconstructs and eliminates the strong GNSS signals broadcast by the enhanced satellite, i.e., co-frequency multiple access interference. This greatly improves the ability of the GNSS receiving terminal to acquire weak GNSS signals under enhanced satellite power conditions, enabling the GNSS receiving terminal to acquire and receive weak GNSS signals while receiving strong GNSS signals. This provides support for improving the positioning success rate and positioning and timing accuracy of the GNSS terminal.
[0059] It should be understood that, although Figure 1 The steps in the flowchart are shown sequentially as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order in which these steps are executed, and they can be performed in other orders. Furthermore, Figure 1 At least some of the steps in the process may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least some of the sub-steps or stages of other steps.
[0060] In one embodiment, such as Figure 4 As shown, a GNSS weak signal acquisition device under enhanced satellite power conditions is provided, comprising: a signal acquisition module 200, a co-frequency multiple access interference reconstruction module 210, an interference cancellation module 220, a time-frequency two-dimensional search module 230, and a target signal acquisition module 240, wherein: The signal acquisition module 200 is used to acquire the signal to be processed, which is the signal after preprocessing by the GNSS receiving terminal.
[0061] The co-channel multiple access interference reconstruction module 210 is used to estimate the amplitude and phase of the co-channel multiple access interference based on the signal to be processed and the corresponding signal envelope, and to reconstruct the co-channel multiple access interference based on the amplitude and phase of the co-channel multiple access interference.
[0062] The interference cancellation module 220 is used to cancel the co-frequency multiple access interference in the signal to be processed by using the reconstructed co-frequency multiple access interference to obtain the interference-cancelled signal.
[0063] The time-frequency two-dimensional search module 230 is used to construct a detection statistic based on the interference-cancelled signal and perform a time-frequency two-dimensional search on the detection statistic.
[0064] The target signal acquisition module 240 is used to determine whether a target signal has been acquired based on the time-frequency two-dimensional search results and through threshold decision, and to estimate the parameters of the target signal when the target signal is acquired.
[0065] Specific limitations regarding the GNSS weak signal acquisition device under enhanced satellite power conditions can be found in the above-mentioned limitations on the GNSS weak signal acquisition method under enhanced satellite power conditions, and will not be repeated here. Each module in the aforementioned GNSS weak signal acquisition device under enhanced satellite power conditions can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in hardware or independently of the processor in a computer device, or stored in software in the memory of a computer device, so that the processor can call and execute the corresponding operations of each module.
[0066] In one embodiment, a computer device is provided, which may be a terminal, and its internal structure diagram may be as follows: Figure 5 As shown, the computer device includes a processor, memory, network interface, display screen, and input devices connected via a system bus. The processor provides computing and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The network interface is used for communication with external terminals via a network connection. When executed by the processor, the computer program implements a method for capturing weak GNSS signals under enhanced satellite power conditions. The display screen can be an LCD screen or an e-ink screen. The input devices can be a touch layer covering the display screen, buttons, a trackball, or a touchpad on the computer device's casing, or an external keyboard, touchpad, or mouse.
[0067] Those skilled in the art will understand that Figure 5 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.
[0068] In one embodiment, a computer device is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to perform the following steps: Acquire the signal to be processed, which is the signal preprocessed by the GNSS receiving terminal; Based on the signal to be processed and the corresponding signal envelope, estimate the amplitude and phase of the co-channel multiple access interference, and reconstruct the co-channel multiple access interference based on the amplitude and phase of the co-channel multiple access interference. The co-frequency multiple access interference obtained from reconstruction is used to cancel the co-frequency multiple access interference in the signal to be processed, resulting in a signal after interference cancellation. A detection statistic is constructed based on the interference-cancelled signal, and a time-frequency two-dimensional search is performed on the detection statistic. Based on the time-frequency two-dimensional search results, a threshold decision is made to determine whether the target signal has been captured, and the parameters of the target signal are estimated when the target signal is captured.
[0069] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon, the computer program performing the following steps when executed by a processor: Acquire the signal to be processed, which is the signal preprocessed by the GNSS receiving terminal; Based on the signal to be processed and the corresponding signal envelope, estimate the amplitude and phase of the co-channel multiple access interference, and reconstruct the co-channel multiple access interference based on the amplitude and phase of the co-channel multiple access interference. The co-frequency multiple access interference obtained from reconstruction is used to cancel the co-frequency multiple access interference in the signal to be processed, resulting in a signal after interference cancellation. A detection statistic is constructed based on the interference-cancelled signal, and a time-frequency two-dimensional search is performed on the detection statistic. Based on the time-frequency two-dimensional search results, a threshold decision is made to determine whether the target signal has been captured, and the parameters of the target signal are estimated when the target signal is captured.
[0070] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in a variety of forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), RAMbus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.
[0071] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0072] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.
Claims
1. A GNSS weak signal acquisition method under satellite power enhancement conditions, characterized in that, The method package: Acquire the signal to be processed, which is the signal preprocessed by the GNSS receiving terminal; Based on the signal to be processed and the corresponding signal envelope, estimate the amplitude and phase of the co-channel multiple access interference, and reconstruct the co-channel multiple access interference based on the amplitude and phase of the co-channel multiple access interference. The co-frequency multiple access interference obtained from reconstruction is used to cancel the co-frequency multiple access interference in the signal to be processed, resulting in a signal after interference cancellation. A detection statistic is constructed based on the interference-cancelled signal, and a time-frequency two-dimensional search is performed on the detection statistic. Based on the time-frequency two-dimensional search results, a threshold decision is made to determine whether the target signal has been captured, and the parameters of the target signal are estimated when the target signal is captured.
2. The GNSS weak signal acquisition method under satellite power enhancement conditions according to claim 1, characterized in that, The signal to be processed is a complex sequence obtained by amplifying, filtering, quadrature downconverting and sampling quantization of the electromagnetic signal received by the GNSS receiving terminal.
3. The GNSS weak signal acquisition method under satellite power enhancement conditions according to claim 1, characterized in that, Based on the signal envelope of the signal to be processed, the amplitude of co-channel multiple access interference is estimated using the following formula: In the above formula, This represents the signal envelope. Represents a positive integer, indicating the data length used to estimate the amplitude of co-channel multiple access interference.
4. The GNSS weak signal acquisition method under satellite power enhancement conditions according to claim 1, characterized in that, Based on the signal to be processed, the phase of co-channel multiple access interference is estimated using the following formula: In the above formula, This indicates the phase take operation.
5. The GNSS weak signal acquisition method under satellite power enhancement conditions according to claim 1, characterized in that, The reconstructed co-channel multiple access interference is represented as: In the above formula, , These represent the amplitude and phase of co-channel multiple access interference, respectively.
6. The GNSS weak signal acquisition method under satellite power enhancement conditions according to claim 1, characterized in that, The detection statistics constructed based on the interference-cancelled signal are expressed as follows: In the above formula, For the test statistic, the value is taken from curly braces. The maximum value of the expression in the curly braces. The value of the expression in the expression is determined by frequency. and latency Sure, This refers to the signal after eliminating co-channel multiple access interference. For weak GNSS signals, a pseudo-random code sequence. The length of the relevant integral operation.
7. The GNSS weak signal acquisition method under satellite power enhancement conditions according to claim 6, characterized in that, When performing a time-frequency two-dimensional search on the detection statistic, the time-frequency two-dimensional search result is when the detection statistic reaches its maximum value, as shown below: In the above formula, frequency and latency At that time, the detection statistic reached its maximum value.
8. The GNSS weak signal acquisition method under satellite power enhancement conditions according to claim 7, characterized in that, The time-frequency two-dimensional search result, which uses a threshold decision to determine whether a target signal has been captured, and estimates the parameters of the target signal when it is captured, includes: A decision threshold is determined based on a preset false alarm probability, and the time-frequency two-dimensional search result is compared with the decision threshold. If the time-frequency two-dimensional search result is greater than the decision threshold, it is determined that the target GNSS weak signal has been successfully captured. At the same time, the frequency and time delay corresponding to the maximum value of the detection statistics during the time-frequency two-dimensional search process are extracted. The frequency is used as the Doppler frequency estimate of the target GNSS weak signal, and the time delay is used as the pseudo-code phase estimate of the target GNSS weak signal. If the detection statistic is not greater than the decision threshold, it is determined that the target GNSS weak signal was not captured.
9. A GNSS weak signal acquisition device under satellite power enhancement conditions, characterized in that, The device includes: The signal acquisition module is used to acquire the signal to be processed, which is the signal preprocessed by the GNSS receiving terminal. The co-channel multiple access interference reconstruction module is used to estimate the amplitude and phase of the co-channel multiple access interference based on the signal to be processed and the corresponding signal envelope, and to reconstruct the co-channel multiple access interference based on the amplitude and phase of the co-channel multiple access interference. The interference cancellation module is used to cancel the co-frequency multiple access interference in the signal to be processed using the reconstructed co-frequency multiple access interference, so as to obtain the interference-cancelled signal. A time-frequency two-dimensional search module is used to construct a detection statistic based on the interference-cancelled signal and to perform a time-frequency two-dimensional search on the detection statistic. The target signal acquisition module is used to determine whether a target signal has been acquired based on the time-frequency two-dimensional search results and through threshold decision, and to estimate the parameters of the target signal when it is acquired.