Satellite time service device anti-interference method and system and electronic equipment

Abstract

The invention belongs to the technical field of satellite time service, and particularly relates to an anti-interference method and system for a satellite time service device and electronic equipment. The method comprises the following steps: expanding a space-time signal into a two-dimensional space-time signal; interference deception signals in the two-dimensional space-time signals are detected and filtered out, so that safe space-time signals are obtained and sent to a satellite time service device; the method for expanding the space-time signals into the two-dimensional space-time signals adopts any one of the following two methods: the first method: enabling a satellite receiving antenna to continuously collect the signals for multiple times at a preset time interval, giving a weight to the signals collected each time, and carrying out weighted summation; according to the second method, the satellite receiving antennas are spaced by a preset angle so as to collect a plurality of signals at different antenna angles at the same moment, and each signal is endowed with a weight and weighted summation is carried out. By adopting the method provided by the invention, the anti-interference performance of the satellite time service device can be greatly improved, and safe and stable operation of a communication system is further ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of satellite timing, and in particular relates to an anti-interference method, system and electronic equipment for a satellite timing device. Background Art

[0002] With the rapid development of my country's satellite navigation system and its wide application in military and civilian fields, the problem of user receivers being susceptible to interference has become increasingly prominent. Due to the extremely high orbit of the satellite, the satellite signal level received by the receiver is very weak. Its power is only about one-tenth of the power of the broadcast signal we listen to in our lives, which makes the receiver extremely susceptible to interference. Satellite timing is the main means for achieving time synchronization for major national infrastructure such as electricity and mobile communications. In the civilian field, satellite timing uses civilian signals with public formats. The satellite timing receiving module is easily attacked by counterfeit deception signals and outputs incorrect time information, which brings great hidden dangers to the safe and stable operation of power, communication and other systems. In order to prevent counterfeit deception signal attacks, it is necessary to identify and filter out the deception signals received by the satellite receiving antenna. The existing anti-interference method of the satellite timing module is to directly identify and filter out the deception interference signal. However, since the satellite signals received by the satellite receiving antenna are one-dimensional space-time signals, the signal redundancy is poor and the space-time signal information is less, the accuracy of identifying interference and deception signals is low. If the interference and deception signals are not identified, the satellite timing device will output incorrect time information, posing a huge hidden danger to the safe and stable operation of power, communication and other systems. Summary of the invention

[0003] The purpose of the present invention is to provide an anti-interference method, system and electronic equipment for a satellite timing device, so as to solve the problem in the prior art that the accuracy of identifying deceptive interference signals received by a satellite receiving antenna is low, resulting in the satellite timing device outputting erroneous time information, which in turn brings great hidden dangers to the safe and stable operation of power, communication and other systems.

[0004] In order to solve the above technical problems, the present invention provides a satellite timing device anti-interference method, comprising the following steps:

[0005] 1) Expanding the space-time signal into a two-dimensional space-time signal, and the expansion method is any of the following:

[0006] The first method is to make the satellite receiving antenna continuously collect multiple signals at a preset time interval, assign weights to each collected signal and perform weighted summation, and the obtained signal is used as the two-dimensional space-time signal corresponding to the first collected signal;

[0007] The second method is to collect multiple signals from different antenna angles at the same time by setting the satellite receiving antennas at preset angles, assign weights to each signal and perform weighted summation to obtain the signal as the two-dimensional space-time signal at that moment;

[0008] 2) Detect and filter out interference and deception signals in the two-dimensional space-time signal, thereby obtaining a safe space-time signal and sending the safe space-time signal to a satellite timing device.

[0009] The beneficial effects are as follows: the satellite signal received by the satellite receiving antenna is a one-dimensional space-time signal, the signal redundancy is poor, and the space-time signal information is less. The anti-interference method of the satellite timing device of the present invention expands the one-dimensional space-time signal to two dimensions, thereby greatly increasing the redundancy of the space-time signal, making the information of the space-time signal richer, and making it easier to identify interference deception signals, thereby ensuring that the interference deception signals in the space-time signal can be accurately identified. The method of the present invention can greatly improve the accuracy of identifying deception signals, thereby greatly improving the anti-interference performance of the satellite timing device, ensuring the accuracy of the time information it outputs, and then ensuring the safe and stable operation of power, communication and other systems.

[0010] Preferably, the method for determining whether a two-dimensional space-time signal is an interference and deception signal includes:

[0011] The signal is subjected to multi-peak detection to obtain the number of correlation peaks of the signal exceeding the capture threshold; if the number of correlation peaks of the signal exceeding the capture threshold is greater than 1 and the power of the signal is abnormal, the signal is determined to be an interference deception signal; the number of correlation peaks exceeding the capture threshold is obtained from the multi-peak detection experimental results of the signal.

[0012] Preferably, if the number of correlation peaks of the signal exceeding the capture threshold is equal to 1 and the half-peak width of the correlation peak is greater than the power detection threshold Vm, the signal is determined to be an interference deception signal.

[0013] Preferably, if the number of correlation peaks of the signal exceeding the capture threshold is equal to 1 and the half-peak width of the correlation peak is not greater than the power detection threshold Vm and the absolute value of the difference between the Doppler offset of the signal and the Doppler offset of the real navigation signal is greater than the first threshold, then the signal is determined to be an interference deception signal.

[0014] Preferably, if the number of correlation peaks of the signal that exceed the capture threshold is equal to 1 and the half-peak width of the correlation peak is not greater than the power detection threshold Vm and the absolute value of the difference between the Doppler offset of the signal and the Doppler offset of the true navigation signal is not greater than the first threshold and the Doppler change rate of the signal is inconsistent with the Doppler change rate of the true navigation signal, then the signal is determined to be an interference deception signal.

[0015] Preferably, the space-time signal is the space-time signal after filtering out interference noise signals.

[0016] The beneficial effect is that the anti-interference performance of the satellite timing device is further improved by filtering the noise signal.

[0017] Preferably, the method for filtering out interference noise signals in the space-time signal comprises the following steps:

[0018] 1.1) Delay the space-time signal by several time units;

[0019] 1.2) Convert the delayed space-time signal and the delayed space-time signal into frequency domain space-time signals respectively;

[0020] 1.3) The components in the frequency domain space-time signal that are greater than a preset power threshold are defined as interference noise signals, and the interference noise signals are filtered out after being identified;

[0021] 1.4) Restore the two signals obtained in step 1.3) to time-domain space-time signals respectively, and superimpose the two signals together.

[0022] The beneficial effects are as follows: signal interference will destroy the original spectrum distribution, and the uninterrupted part will maintain the Gaussian characteristic, resulting in different powers of the interference noise signal and the effective space-time signal. Therefore, the effective space-time signal and the interference noise signal can be effectively distinguished through this characteristic; reducing narrowband interference through frequency domain elimination can remove narrowband interference while keeping other frequency components unchanged, reducing strong narrowband interference, improving communication quality, and finally obtaining a good interference suppression effect; the method of filtering out the interference noise signal in the original space-time signal can effectively filter out the interference noise signal in the original space-time signal, thereby further improving the anti-interference performance of the satellite timing device.

[0023] Preferably, the number of time units for delaying the space-time signal is half.

[0024] The beneficial effect is that by delaying the space-time signal by half a time unit, the attenuation of the signal-to-noise ratio can be greatly reduced. Therefore, by delaying the space-time signal by half a time unit and superimposing the delayed space-time signal with the space-time signal before the delay, the loss of the signal-to-noise ratio of the space-time signal can be greatly reduced, thereby ensuring the fidelity of the space-time signal.

[0025] In order to solve the above technical problems, the present invention also provides a satellite timing device anti-interference system, characterized in that it includes:

[0026] The high-dimensional processing module of the space-time signal is used to expand the space-time signal into a two-dimensional space-time signal; and the space-time signal is expanded into a two-dimensional space-time signal by any one of the following two methods:

[0027] The first method is to make the satellite receiving antenna continuously collect multiple signals at a preset time interval, assign weights to each collected signal and perform weighted summation, and the obtained signal is used as the two-dimensional space-time signal corresponding to the first collected signal;

[0028] The second method is to collect multiple signals from different antenna angles at the same time by setting a preset angle between satellite receiving antennas, assign a weight to each signal and perform weighted summation to obtain the signal as the two-dimensional space-time signal at that moment.

[0029] A satellite deception interference signal identification module is used to detect and filter out interference deception signals in the two-dimensional space-time signal;

[0030] The signal sending module is used to send secure space-time signals to the satellite timing device.

[0031] The beneficial effects are as follows: the satellite signal received by the satellite receiving antenna is a one-dimensional space-time signal, the signal redundancy is poor, and the space-time signal information is less. The anti-interference system of the satellite timing device of the present invention expands the one-dimensional space-time signal to two dimensions, thereby greatly increasing the redundancy of the space-time signal, making the information of the space-time signal richer, and making it easier to identify interference deception signals, thereby ensuring that the interference deception signals in the space-time signal can be accurately identified. The system of the present invention can greatly improve the anti-interference performance of the satellite timing device, ensure the accuracy of the time information it outputs, and then ensure the safe and stable operation of power, communication and other systems.

[0032] To solve the above technical problems, the present invention further provides an electronic device, including a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the anti-interference method of the satellite timing device of the present invention is implemented. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is a flow chart of the method steps of the present invention;

[0034] Figure 2 is a flow chart of a method for filtering out interference noise signals of the present invention;

[0035] Figure 3 It is a schematic diagram of the expansion of space-time signal;

[0036] Figure 4 It is a flow chart of a method for detecting deceptive interference signals of the present invention;

[0037] Figure 5 It is a schematic diagram of the structure of the anti-interference system of the satellite timing device of the present invention. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0039] Satellite timing device anti-interference method embodiment:

[0040] like Figure 1 As shown, the satellite timing device anti-interference method of the present invention comprises the following steps:

[0041] Step 1: filter out the interference noise signal in the original space-time signal received by the satellite receiving antenna.

[0042] After filtering out the interference noise signal, a cleaner space-time signal can be obtained and the anti-interference performance of the satellite timing device can be improved. Before filtering out the interference noise signal, the original space-time signal needs to be converted into a frequency domain space-time signal. Figure 2 As shown, the specific method of filtering out the interference noise signal in the received original space-time signal is as follows:

[0043] 1.1) Delay the original space-time signal by several time units;

[0044] The original space-time signal can be delayed by half a time unit;

[0045] 1.2) Perform windowing processing on the original space-time signal and the delayed space-time signal respectively;

[0046] Windowing can avoid spectrum energy leakage and make the frequency point connection smoother.

[0047] 1.3) Convert the delayed space-time signal and the delayed space-time signal into frequency domain space-time signals respectively;

[0048] The space-time signal can be converted into a frequency domain space-time signal by using Fast Fourier Transform (FFT) or other suitable methods.

[0049] 1.4) Set the power threshold of the signal, define the component in the frequency domain space-time signal that is greater than the threshold as the interference noise signal, and filter out the interference noise signal after identifying it;

[0050] 1.5) Recover the delayed space-time signal after filtering out the interference noise signal and the delayed space-time signal before filtering out the interference noise signal into time domain space-time signals respectively, and superimpose the two together.

[0051] The frequency domain space-time signal may be converted into the time domain space-time signal by using an inverse Fourier transform (IFFT) or other suitable methods.

[0052] By filtering out noise signals in the frequency domain, narrowband interference can be reduced.

[0053] By using 50% overlap, the attenuation of the signal-to-noise ratio can be reduced. Therefore, by delaying half a time unit to superimpose the denoised signal after the delay and the denoised signal before the delay, the loss of the signal-to-noise ratio can be greatly reduced. The original signal will be subject to various forms of interference on the way to the device. Signal interference will destroy the original spectrum distribution, and the uninterrupted part will maintain the Gaussian characteristics, resulting in different powers of the interference noise signal and the effective signal in time and space. Therefore, this characteristic can be used to effectively distinguish the effective signal in time and space from the interference noise signal; by analyzing the type of information interference, it can be found that strong narrowband interference has the best effect. A cascade anti-interference algorithm is designed for strong narrowband interference. Reducing narrowband interference by eliminating narrowband interference in the frequency domain can remove narrowband interference while keeping other frequency components unchanged, reducing strong narrowband interference, improving communication quality, and finally obtaining a good interference suppression effect; the method of filtering out interference noise signals in the original space-time signal of the present invention can effectively filter out interference noise signals in the original space-time signal.

[0054] Step 2: Expand the space-time signal after filtering out the interference noise into a two-dimensional space-time signal.

[0055] The satellite signal received by the satellite receiving antenna is a one-dimensional space-time signal. Expanding the one-dimensional space-time signal to two dimensions can increase the redundancy of the space-time signal, making the space-time signal more informative and easier to identify interference and deception signals. Generally, higher dimensions are accompanied by richer input information, but the amount of calculation will increase exponentially, resulting in an increase in the processing time of the recognition module, thereby affecting the processing speed of the device. In this embodiment, the method of expanding the space-time signal to a two-dimensional signal is as follows: Figure 3 As shown, the one-dimensional space-time signal is expanded into a two-dimensional space-time signal by using any of the following two methods:

[0056] The first method is to enable the satellite receiving antenna to continuously collect multiple signals at preset time intervals, assign weights to the signals collected each time and perform weighted summation, and the obtained signal is used as the two-dimensional space-time signal corresponding to the signal collected for the first time; the preset time interval can be 1 second or other suitable time lengths; the number of continuous signal collection times can be three times or other suitable times.

[0057] The second method is to collect multiple signals from different antenna angles at the same time by setting the satellite receiving antennas at preset angles, assign weights to each signal and perform weighted summation to obtain the signal as the two-dimensional space-time signal at that moment;

[0058] The preset angle may be 120 degrees or other suitable angles; the number of collected signals is equal to the quotient obtained by dividing 360 by the preset degree.

[0059] The time corresponding to the two-dimensional space-time signal obtained in the first method is the same as the time corresponding to the signal collected for the first time. Step three, detecting the interference deception signal in the two-dimensional space-time signal.

[0060] The different characteristic information of the deceptive jamming signal is used to detect the deceptive jamming signal by using the joint detection method in signal capture and tracking, such as Figure 4 As shown, judging whether a two-dimensional space-time signal is an interference deception signal specifically includes the following steps:

[0061] 3.1) Perform multi-peak detection on the signal to determine the number of correlation peaks exceeding the capture threshold. If the number of correlation peaks exceeding the capture threshold is 0, it indicates that there is no navigation signal in the receiver channel. If the number of correlation peaks exceeding the capture threshold is greater than 1, execute step 3.2); if the number of correlation peaks exceeding the capture threshold is equal to 1, execute step 3.3);

[0062] 3.2) Detect the power of the signal. If the power is abnormal, the signal is judged as an interference deception signal; if the power is normal, the signal is judged as a navigation signal;

[0063] 3.3) Perform half-maximum full width detection on the signal to obtain the half-maximum width of its captured correlation peak, and compare the half-maximum width of the captured correlation peak with the power detection threshold Vm. If the half-maximum width of the captured correlation peak is greater than Vm, the signal is determined to be an interference deception signal, otherwise, the next step is executed;

[0064] 3.4) detecting the Doppler shift of the signal. If the absolute value of the difference between the Doppler shift and the Doppler shift of the real navigation signal is greater than a first threshold, the signal is determined to be an interference deception signal; otherwise, proceed to the next step;

[0065] 3.5) Detect the Doppler change rate of the signal and compare it with the Doppler change rate of the real navigation signal. If the two are consistent, the signal is determined to be a navigation signal; otherwise, the signal is determined to be an interference deception signal.

[0066] Generative deception jamming signals and forwarding deception jamming signals are the two main types of deception jamming signals. Generative deception jamming simulates the real signal of the satellite and fabricates false navigation information to the target receiver to produce false positioning results. Generative deception jamming autonomously transmits navigation signals similar to real satellite signals on the premise of knowing the signal code structure. Forwarding deception jamming controls the delay and power of the forwarded signal so that the target receiver can use the forwarded signal for positioning and calculate the wrong coordinates, thereby achieving the purpose of deception jamming. The hardware cost required for forwarding deception jamming is low, the interference source has a large interference range and is easy to implement. Although forwarding deception jamming cannot use the delay of the signal to spoof the user coordinates to any given position, for areas with high requirements for navigation positioning and timing, even inaccurate forwarding deception jamming can also cause fatal damage to civilian and military equipment. Since the target receiver does not know what kind of characteristic form of forwarding deception jamming it will be subjected to, the deception jamming cannot be completely and effectively detected by a single deception detection method. At this time, multiple methods are required for joint detection. The method of the present invention for determining whether a two-dimensional space-time signal is an interference deception signal utilizes different characteristic information of the deception interference signal to detect the interference deception signal by adopting a plurality of methods for joint detection in the signal capture stage and the tracking stage, thereby greatly improving the accuracy of the detection of the deception interference signal.

[0067] Step 4: Filter out the interference and deception signals in the two-dimensional space-time signal to obtain a safe space-time signal and send the safe space-time signal to the satellite timing device.

[0068] The secure time and space signal can be sent to the satellite timing device through the radio frequency module.

[0069] The interference signal received by the satellite receiving antenna may include both interference noise signal and interference deception signal; the anti-interference method of the satellite timing device of the present invention first filters out the interference noise signal in the original space-time signal to obtain a cleaner space-time signal, and then filters out the interference deception signal to obtain a safe space-time signal and send it to the timing device. The method of the present invention filters out both the interference noise signal and the interference deception signal received by the satellite receiving antenna, thereby more comprehensively ensuring the security of the space-time signal; the satellite signal received by the satellite receiving antenna is a single-dimensional space-time signal, the signal redundancy is poor, and the space-time signal information is less. By expanding the single-dimensional space-time signal to two dimensions, the redundancy of the space-time signal is greatly increased, making the information of the space-time signal richer, and it is easier to identify the interference deception signal, thereby ensuring that the interference deception signal in the space-time signal can be accurately identified. The method of the present invention can greatly improve the anti-interference performance of the satellite timing device, ensure the accuracy of the time information output by it, and then ensure the safe and stable operation of power, communication and other systems.

[0070] Satellite timing device anti-interference system embodiment:

[0071] like Figure 5 As shown, the satellite timing device anti-interference system of the present invention comprises:

[0072] A high-dimensional processing module for space-time signals, used to expand space-time signals into two-dimensional space-time signals;

[0073] A satellite deception interference signal identification module is used to detect and filter out interference deception signals in the two-dimensional space-time signal;

[0074] The signal sending module is used to send the secure space-time signal to the satellite timing device; the space-time signal high-dimensional processing module expands the space-time signal into a two-dimensional space-time signal using any of the following two methods:

[0075] The first method is to make the satellite receiving antenna continuously collect multiple signals at a preset time interval, assign weights to each collected signal and perform weighted summation, and the obtained signal is used as the two-dimensional space-time signal corresponding to the first collected signal;

[0076] The second method is to collect multiple signals from different antenna angles at the same time by setting a preset angle between satellite receiving antennas, assign a weight to each signal and perform weighted summation to obtain the signal as the two-dimensional space-time signal at that moment.

[0077] The satellite signal received by the satellite receiving antenna is a one-dimensional space-time signal, the signal redundancy is poor, and the space-time signal information is less. The satellite timing device anti-interference system of the present invention expands the one-dimensional space-time signal to two dimensions, thereby greatly increasing the redundancy of the space-time signal, making the space-time signal information richer, and easier to identify interference deception signals, thereby ensuring that the interference deception signals in the space-time signal can be accurately identified. The system of the present invention can greatly improve the anti-interference performance of the satellite timing device, ensure the accuracy of the time information it outputs, and then ensure the safe and stable operation of power, communication and other systems.

[0078] The satellite timing device anti-interference system of the present invention corresponds to the satellite timing device anti-interference method of the present invention, and each module thereof corresponds to each step of the satellite timing device anti-interference method of the present invention.

[0079] Electronic device embodiment:

[0080] The electronic device of the present invention comprises a memory and a processor. The memory stores a computer program. When the computer program is executed by the processor, the anti-interference method of the satellite timing device of the present invention is implemented.

[0081] The processor may be a microprocessor MCU, a programmable logic device FPGA or other processing device.

[0082] The memory can be any type of memory that uses electrical energy to store information.

Claims

1. A satellite timing device anti-interference method, characterized in that: The following steps are involved: 1) Expanding the space-time signal into a two-dimensional space-time signal, and the expansion method is any of the following: The first method is to make the satellite receiving antenna continuously collect multiple signals at a preset time interval, assign weights to each collected signal and perform weighted summation, and the obtained signal is used as the two-dimensional space-time signal corresponding to the first collected signal; The second method is to collect multiple signals from different antenna angles at the same time by setting the satellite receiving antennas at preset angles, assign weights to each signal and perform weighted summation to obtain the signal as the two-dimensional space-time signal at that moment; 2) Detect and filter out interference and deception signals in the two-dimensional space-time signal, thereby obtaining a safe space-time signal and sending the safe space-time signal to a satellite timing device.

2. The anti-interference method for a satellite timing device as claimed in claim 1, characterized in that: Methods for determining whether a two-dimensional space-time signal is an interference deception signal include: Perform multi-peak detection on the signal to obtain the number of correlation peaks of the signal that exceed the capture threshold; if the number of correlation peaks of the signal that exceeds the capture threshold is greater than 1 and the power of the signal is abnormal, the signal is determined to be an interference deception signal.

3. The anti-interference method for a satellite timing device as claimed in claim 2, characterized in that: If the number of correlation peaks of the signal exceeding the capture threshold is equal to 1 and the half-peak width of the correlation peak is greater than the power detection threshold Vm, the signal is determined to be an interference deception signal.

4. The anti-interference method for a satellite timing device as claimed in claim 2, characterized in that: If the number of correlation peaks of the signal that exceed the capture threshold is equal to 1 and the half-peak width of the correlation peak is not greater than the power detection threshold Vm, and the absolute value of the difference between the Doppler shift of the signal and the Doppler shift of the real navigation signal is greater than the first threshold, then the signal is determined to be an interference deception signal.

5. The anti-interference method for a satellite timing device as claimed in claim 2, characterized in that: If the number of correlation peaks of the signal that exceed the capture threshold is equal to 1 and the half-peak width of the correlation peak is not greater than the power detection threshold Vm, and the absolute value of the difference between the Doppler offset of the signal and the Doppler offset of the true navigation signal is not greater than the first threshold, and the Doppler change rate of the signal is inconsistent with the Doppler change rate of the true navigation signal, then the signal is determined to be an interference deception signal.

6. The anti-interference method for a satellite timing device according to any one of claims 1 to 5, characterized in that: The space-time signal is the space-time signal after the interference noise signal is filtered out.

7. The anti-interference method for a satellite timing device as claimed in claim 6, characterized in that: The method for filtering out interfering noise signals in a space-time signal comprises the following steps: 1.1) Delay the space-time signal by several time units; 1.2) Convert the delayed space-time signal and the delayed space-time signal into frequency domain space-time signals respectively; 1.3) The components in the frequency domain space-time signal that are greater than a preset power threshold are defined as interference noise signals, and the interference noise signals are filtered out after being identified; 1.4) Restore the two signals obtained in step 1.3) to time-domain space-time signals respectively, and superimpose the two signals together.

8. The anti-interference method for a satellite timing device as claimed in claim 7, characterized in that: The number of time units for delaying the space-time signal is half.

9. A satellite timing device anti-interference system, characterized in that: include: The high-dimensional processing module of the space-time signal is used to expand the space-time signal into a two-dimensional space-time signal, and the space-time signal is expanded into a two-dimensional space-time signal by any one of the following two methods: The first method is to make the satellite receiving antenna continuously collect multiple signals at a preset time interval, assign weights to each collected signal and perform weighted summation, and the obtained signal is used as the two-dimensional space-time signal corresponding to the first collected signal; The second method is to collect multiple signals from different antenna angles at the same time by setting the satellite receiving antennas at preset angles, assign weights to each signal and perform weighted summation to obtain the signal as the two-dimensional space-time signal at that moment; A satellite deception interference signal identification module is used to detect and filter out interference deception signals in the two-dimensional space-time signal; The signal sending module is used to send secure space-time signals to the satellite timing device.

10. An electronic device comprising a memory and a processor, wherein a computer program is stored in the memory, wherein: When the computer program is executed by a processor, the anti-interference method for a satellite timing device according to any one of claims 1 to 8 is implemented.

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