Civil aviation satellite navigation anti-interference and anti-deception method and device

Abstract

The application relates to the technical field of satellite navigation, and particularly discloses a civil aviation satellite navigation anti-interference and anti-deception method and equipment, which comprises the following steps: constructing a multi-beam pointing and multi-stage Wiener filtering anti-interference method, solving an optimal anti-interference weight vector under the maximum output signal-to-noise ratio, and taking into account the maximum interference suppression degree and the minimum satellite signal receiving signal-to-noise ratio loss; detecting whether there is deception in the captured signal after anti-interference through a correlation peak ternary detection and attitude position auxiliary detection method; if there is deception, the deception is suppressed through a deception regeneration cancellation method, and satellite signal purification is realized. The application constructs a multi-beam pointing and multi-stage Wiener filtering anti-interference method, a correlation peak ternary detection, an attitude position auxiliary detection, a deception regeneration cancellation anti-deception method, and has the advantages of being suitable for multiple types of interference, having strong anti-interference ability, being suitable for retransmission / generation type deception, having strong anti-deception ability, and being strong in engineering practicability.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of satellite navigation, in particular to a civil aviation satellite navigation anti-interference and anti-deception method and device. BACKGROUND

[0002] Satellite navigation equipment in practical application is faced with unintentional interference and intentional interference. Unintentional interference mainly comes from satellite positioning system multiple access interference and adjacent navigation band channel interference, etc. Intentional interference can be divided into suppression interference and deception interference from the interference mechanism.

[0003] Suppression interference (hereinafter referred to as interference) can be divided into continuous type and pulse type from the type. Continuous interference types include single tone, multi-tone, sweep, amplitude modulation, phase modulation, frequency modulation, etc. The main characteristic parameters of pulse interference include pulse repetition frequency, duty cycle, carrier frequency, etc. Interference causes the equivalent carrier-to-noise ratio of satellite navigation equipment to decrease, and then the position, velocity and time (PVT) accuracy to deteriorate, even the loop to lose lock, and the equipment to be unable to locate.

[0004] Deception interference (hereinafter referred to as deception) can be divided into repeater type and generator type from the generation mode. Repeater deception is obtained by receiving-amplifying-delaying-transmitting satellite signals. Relative to satellite signals, the time delay is positive, and the power can be strong or weak. Generator deception needs to know satellite signal carrier frequency, modulation mode, spread spectrum code and navigation text, etc. Based on this, deception similar to satellite signal structure but different in time delay and text is generated. Relative to satellite signals, the time delay can be positive or negative, and the power can be strong or weak.

[0005] Satellite navigation anti-interference and anti-deception is one of the important contents of the protection policy in the navigation war "protection, prevention and preservation", and has been a research hotspot in the field of military satellite navigation. Many research results have been successfully transformed and applied on a large scale. However, the research results of military satellite navigation anti-interference and anti-deception are not suitable for civil use, and there is an urgent need for commercialization of mature research results suitable for civil use.

[0006] Existing satellite navigation anti-interference and anti-deception methods are mostly military satellite navigation anti-interference and anti-deception methods for satellite navigation authorized service signals.

[0007] The BDS B1A, B2b, B3A and B3AE satellite navigation authorized service signals adopt a spread spectrum modulation mode, and a non-periodic spread spectrum code used for spreading is generated by a military code level PRM chip which is a core component of a Beidou self-controllable security system, and the generation mode is not disclosed externally, and the generated spread spectrum code stream is not output externally. Since the PRM chip (first phase) supports a limited number of beams, the existing military satellite navigation anti-jamming method adopts an adaptive zero anti-jamming method, and does not adopt a multi-beam pointing anti-jamming method which has stronger anti-jamming capability. Since the PRM chip avoids generating type deception, only retransmission type deception needs to be considered, and therefore the existing military satellite navigation anti-deception method adopts a related peak detection and identification anti-deception method.

[0008] The existing military satellite navigation anti-jamming and anti-deception method is not suitable for being applied to civil aviation satellite navigation anti-jamming and anti-deception, and the main reason lies in that:

[0009] The civil aviation satellite navigation signals BDS B1C and B2a and the GPS L1C / A are public service signals, and a short period spread spectrum code used for spreading is disclosed in a space signal interface control document, and does not need to be generated by a PRM chip. For example, the spread spectrum code generation mode of the Beidou navigation civil signal B1C and B2a is disclosed in the Beidou Satellite Navigation System Space Signal Interface Control Document Public Service Signal B1C (1.0 version) and the Beidou Satellite Navigation System Space Signal Interface Control Document Public Service Signal B2a (1.0 version) issued by the China Satellite Navigation System Management Office.

[0010] In this way, on the one hand, the multi-beam pointing anti-jamming method which has stronger anti-jamming capability can be adopted without being limited by the support capability of the number of beams of the PRM chip. On the other hand, the multi-beam pointing anti-jamming method does not enjoy the privilege of avoiding the generation type deception of the PRM chip, and both the retransmission type deception and the generation type deception need to be considered. Compared with the retransmission type deception, the generation type deception has positive or negative time delay relative to the satellite signal, and has stronger deception (no positive time delay prior information is available), so that the conventional related peak detection and identification method is invalid, and more strict signal detection, information verification and other technologies need to be combined.

[0011] Based on this technical background, the present application studies a civil aviation satellite navigation anti-jamming and anti-deception method and device. SUMMARY

[0012] In view of the deficiencies of the prior art, the present application provides a civil aviation satellite navigation anti-jamming and anti-deception method and device. The method is aimed at the civil aviation anti-jamming and anti-deception requirements, constructs a multi-beam pointing and multi-level Wiener filtering anti-jamming method, and has the advantages of being suitable for multiple types of interference, having strong anti-jamming capability, and having strong engineering practicability. Meanwhile, by constructing a related peak ternary detection, an attitude and position auxiliary detection and a deception regeneration counter deception method, the method has the advantages of adapting to the retransmission / generation type deception, having strong anti-deception capability and strong engineering practicability.

[0013] To achieve the above object, the first aspect of the present application provides a civil aviation satellite navigation anti-jamming and anti-deception method, comprising:

[0014] By constructing a multi-beam pointing and multi-stage Wiener filtering anti-jamming method, the optimal anti-jamming weight vector under the maximum output signal-to-interference-and-noise ratio is solved, so as to maximize the interference suppression degree and minimize the loss of satellite signal reception signal-to-noise ratio.

[0015] By the correlation peak ternary detection method and the attitude position auxiliary detection method, it is detected whether there is deception in the captured signal after anti-jamming; if there is deception, the deception in the captured signal is suppressed by the deception regeneration cancellation method, so as to realize satellite signal purification.

[0016] The second aspect of the present application provides a civil aviation satellite navigation anti-jamming and anti-deception device used in the above, comprising:

[0017] The array antenna comprises 4 B1C frequency band antenna elements, 4 B2a frequency band antenna elements, a feed network and an array surface.

[0018] The radio frequency channel comprises 4 B1C frequency band down-conversion units and 4 B2a frequency band down-conversion units, and is used for filtering, frequency conversion and amplification processing of the satellite signals and / or interference and / or deception received by the 4 B1C frequency band antenna elements and the 4 B2a frequency band antenna elements to obtain 8 analog signals.

[0019] The digital processing unit is connected with the output of the radio frequency channel, and is used for converting the 8 analog signals transmitted by the radio frequency channel into 8 digital intermediate frequency signals, and performing multi-beam anti-jamming, navigation signal processing, navigation information processing and anti-deception processing on the 8 digital intermediate frequency signals.

[0020] The interface unit comprises a radio frequency interface, a data interface and a power supply interface, the radio frequency interface is used for radio frequency input and feed output, the data interface is used for data transmission and information annotation, and the power supply interface is used for external power supply input and isolation processing.

[0021] The power supply unit is used for converting an external power supply voltage into voltages required by the array antenna, the radio frequency channel and the digital processing unit.

[0022] The beneficial effects of the present application include:

[0023] (1) The civil aviation satellite navigation anti-interference and deception prevention method provided by the application has the advantages of being suitable for multiple types of interference, having strong anti-interference ability, and being strong in engineering practicability.

[0024] (2) The civil aviation satellite navigation anti-interference and deception prevention method provided by the application first establishes a multi-beam pointing anti-interference model based on minimum variance distortionless response, so that the minimum output variance is subordinate to the single satellite signal orientation gain, and the optimal anti-interference weight vector ensures interference suppression and high signal-to-noise ratio satellite navigation reception.

[0025] (3) The civil aviation satellite navigation anti-interference and deception prevention method provided by the application constructs a correlation peak ternary detection, attitude position auxiliary detection, and deception regeneration countermeasure deception method for the civil aviation satellite navigation deception prevention demand.

[0026] (4) The civil aviation satellite navigation anti-interference and deception prevention equipment provided by the application is designed to have a hardware platform of a parallel processing and expandable platform of a dual-frequency 8-channel low-noise radio frequency front end, an expandable FPGA+DSP heterogeneous structure, and a modular interface.

[0027] Other features and advantages of the application will be described in detail in the following specific embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0028] The above and other objects, features and advantages of the present application will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings in which:

[0029] Figure 1 A flowchart of a civil aviation satellite navigation anti-interference and anti-deception method is provided in the present application.

[0030] Figure 2 A specific embodiment of a civil aviation satellite navigation anti-interference and anti-deception device is provided in the present application.

[0031] Figure 3 A specific embodiment of a civil aviation satellite navigation anti-interference and anti-deception device is provided in the present application.

[0032] Figure 4 A specific embodiment of a civil aviation satellite navigation anti-interference and anti-deception device is provided in the present application. DETAILED DESCRIPTION

[0033] The preferred embodiments of the present application will be described in more detail below. Although the preferred embodiments of the present application are described below, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments described herein.

[0034] The present application provides a civil aviation satellite navigation anti-interference and anti-deception method, as shown in Figure 1 , comprising:

[0035] By constructing a multi-beam pointing, multi-stage Wiener filtering anti-interference method, the optimal anti-interference weight vector under the maximum output signal-to-interference-and-noise ratio is solved, so as to maximize the interference suppression degree and minimize the satellite signal reception signal-to-noise ratio loss.

[0036] By the correlation peak ternary detection method and the attitude position auxiliary detection method, it is detected whether there is deception in the captured signal after anti-interference; if there is deception, the deception in the captured signal is suppressed by the deception regeneration cancellation method, and the satellite signal purification is realized.

[0037] In the present application, for the civil aviation anti-interference and anti-deception demand, a multi-beam pointing, multi-stage Wiener filtering anti-interference method is constructed, which has the advantages of being applicable to multiple types of interference, strong anti-interference ability, and strong engineering practicability; at the same time, by constructing the correlation peak ternary detection, attitude position auxiliary detection, and deception regeneration cancellation anti-deception method, it has the advantages of adapting to the retransmission / generation type deception, strong anti-deception ability, and strong engineering practicability.

[0038] According to the present application, by constructing a multi-beam pointing, multi-stage Wiener filtering anti-interference method, the optimal anti-interference weight vector under the maximum output signal-to-interference-and-noise ratio is solved, so as to maximize the interference suppression degree and minimize the satellite signal reception signal-to-noise ratio loss.

[0039] The multi-beam pointing anti-interference model is constructed, and the optimal anti-interference weight vector under the maximum output signal-to-interference-and-noise ratio is the projection of the steering vector in the expected satellite signal direction on the noise subspace;

[0040] The projection matrix of the noise subspace is obtained through multi-stage Wiener filtering;

[0041] The optimal anti-interference weight vector of the anti-interference model is obtained based on the projection matrix;

[0042] The array signal vector of the anti-interference model is weighted and summed by using the optimal anti-interference weight vector, so that the interference in the array signal vector is inhibited to the maximum extent, and the satellite signal in the array signal vector is affected to the minimum extent.

[0043] According to the present application, the anti-interference model is a minimum variance distortionless response constraint optimization model, and the expression of the constraint optimization model is:

[0044] ;

[0045] Wherein, is the covariance matrix of the array signal vector is the steering vector in the expected satellite signal direction, is the anti-interference weight vector, is the conjugate transpose symbol of the vector or matrix;

[0046] The expression of the optimal anti-interference weight vector is:

[0047] ;

[0048] Wherein, is the optimal anti-interference weight vector, is the unit matrix, is the interference steering vector matrix, is the projection matrix of the noise subspace, is the inverse symbol of the matrix, is the number of interferences, is the dimension of the vector;

[0049] The projection matrix of the noise subspace is obtained through multi-stage Wiener filtering, and the corresponding initialization and iteration process are as follows:

[0050] Initialization: , ;

[0051] Iteration times: ;

[0052] ;

[0053] ​ ;

[0054] ;

[0055] ;

[0056] Take the first largest values corresponding to the projection matrix of the noise subspace ;

[0057] wherein, , is the initial value of iteration, is the first element of the vector , is the first standard orthogonal basis vector of the interference subspace, is the mathematical expectation operator, and the symbol is the conjugate operator, is the modulus operator, is the conjugate transpose operator, , , are the expected signals of the first , iterations, respectively, , are the input vectors of the first , iterations, respectively, is the mean square value of the first expected signal.

[0058] According to the application, the correlation peak ternary detection method comprises:

[0059] proposing H0 no expected satellite signal, H1 only expected satellite signal, H2 expected satellite signal and deception ternary hypothesis, determining the test statistic and the probability distribution it obeys, and giving the significance level;

[0060] determining the rejection region critical point under the significance level according to the probability distribution that the test statistic obeys;

[0061] correlating the captured signal after anti-interference with the local spread spectrum code;

[0062] if there is no correlation peak value greater than the critical point in the carrier Doppler frequency shift-spread spectrum code phase two-dimensional search space, it is judged as no expected satellite signal, and the acquisition continues;

[0063] if there is only one correlation peak value greater than the critical point, it is judged as only expected satellite signal and no deception, and directly enters the tracking phase;

[0064] If there are multiple correlation peaks greater than the critical point, then the decision is that the expected satellite signal and deception exist, and the process goes to the deception regenerative cancellation stage;

[0065] Wherein, the test statistic under the H0 hypothesis is subject to a centralized chi-square distribution; the test statistic under the H1, H2 hypothesis is subject to a non-centralized chi-square distribution;

[0066] The attitude position auxiliary detection method comprises:

[0067] The acceptable false alarm rate is determined, and a detection threshold corresponding to the false alarm rate is solved;

[0068] The carrier phase double difference prediction value of all visible satellites is calculated by using the attitude and position information, wherein the maximum carrier phase double difference prediction value is denoted as ;

[0069] The decision is made according to whether the difference between the carrier phase double difference observation value and exceeds the detection threshold, that is, if the difference between the carrier phase double difference observation value and does not exceed the detection threshold, then the decision is that only the expected satellite signal exists, and no deception exists, and the process directly goes to the tracking stage; if the difference between the carrier phase double difference observation value and exceeds the detection threshold, then the decision is that deception exists, and the process goes to the deception regenerative cancellation stage;

[0070] The formula for solving the detection threshold is:

[0071] ;

[0072] Wherein, is the detection threshold, is the false alarm rate, is the probability cumulative distribution function corresponding to the carrier phase double difference observation noise distribution function of the satellite signal;

[0073] The expression of the probability cumulative distribution function is:

[0074] ;

[0075] Wherein, is the carrier phase observation noise variance.

[0076] According to the present application, the deception in the captured signal after the anti-interference is suppressed by the deception regenerative cancellation method, and the satellite signal purification is realized, which comprises:

[0077] The deception in the currently captured signal is tracked to obtain the amplitude estimation value and the phase estimation value of the deception;

[0078] According to the amplitude estimation value, the phase estimation value and the local generated spoofing spread spectrum code according to the interface control file, a regenerated spoofing is obtained;

[0079] The regenerated spoofing is subtracted from the anti-interference and captured signal, and the satellite signal is purified and then input into a tracking unit.

[0080] In the application, firstly, a multi-beam pointing anti-interference model based on minimum variance distortionless response is established, so that the minimum output variance is subordinate to the single satellite signal upward gain, and the optimal anti-interference weight vector is ensured to consider the interference suppression and the low signal-to-noise ratio loss of satellite navigation reception; then, a multi-stage Wiener filter is used to quickly solve the noise subspace projection matrix and the optimal anti-interference weight vector of the multi-beam pointing; finally, the optimal anti-interference weight vector of the multi-beam pointing is used to weight and sum the array signal vector, so that the interference suppression and the high-quality satellite signal reception are realized.

[0081] In the application, for the demand of civil aviation satellite navigation anti-spoofing, a correlation peak ternary detection, an attitude position auxiliary detection and a spoofing regeneration countermeasure method are constructed; whether there is spoofing is detected through the correlation peak ternary detection method and the attitude position auxiliary detection method; if there is spoofing, the spoofing in the captured signal is suppressed through the spoofing regeneration countermeasure method, the satellite signal is purified, and the application has the advantages of strong anti-spoofing ability, strong engineering practicability and the like.

[0082] The application further provides a civil aviation satellite navigation anti-interference anti-spoofing device used in the above method, which comprises:

[0083] The array antenna comprises four B1C frequency band antenna array elements, four B2a frequency band antenna array elements, a feed network and an array surface.

[0084] The radio frequency channel comprises four B1C frequency band down-conversion units and four B2a frequency band down-conversion units, and is used for filtering, frequency conversion and amplification processing of the satellite signals and / or interference and / or spoofing received by the four B1C frequency band antenna array elements and the four B2a frequency band antenna array elements to obtain eight analog signals.

[0085] The digital processing unit is connected with the output of the radio frequency channel, is used for converting the eight analog signals transmitted by the radio frequency channel into eight digital intermediate frequency signals, and is used for multi-beam anti-interference, navigation signal processing, navigation information processing and anti-spoofing processing on the eight digital intermediate frequency signals.

[0086] The interface unit comprises a radio frequency interface, a data interface and a power supply interface, the radio frequency interface is used for radio frequency input and feed output, the data interface is used for data transmission and information annotation, and the power supply interface is used for external power input and isolation processing.

[0087] A power supply unit is configured to convert an external power supply voltage into voltages required by the array antenna, the radio frequency channel and the digital processing unit.

[0088] According to the application, the input end of each B1C frequency band down-conversion unit is connected with the output of one B1C frequency band antenna array element, and the input end of each B2a frequency band down-conversion unit is connected with the output of one B2a frequency band antenna array element.

[0089] The four B1C frequency band down-conversion units and the four B2a frequency band down-conversion units are configured to filter, frequency-convert and amplify satellite signals and / or interference and / or spoofing received by the four B1C frequency band antenna array elements and the four B2a frequency band antenna array elements respectively to obtain eight analog intermediate frequency signals.

[0090] According to the application, the digital processing unit comprises eight analog-to-digital converters, a field programmable gate array chip and a digital signal processing chip.

[0091] The input end of each analog-to-digital converter is connected with the output end of one B1C frequency band down-conversion unit or one B2a frequency band down-conversion unit, and the output end outputs a digital intermediate frequency signal.

[0092] The field programmable gate array chip performs multi-beam anti-interference, navigation signal processing, correlation peak ternary detection and spoofing regeneration countermeasure against spoofing.

[0093] The digital signal processing chip performs navigation information processing, attitude and position auxiliary detection and anti-spoofing processing.

[0094] According to the application, the software running on the field programmable gate array chip comprises an anti-interference module, a capture module, a tracking module, a data demodulation module, a TIXX module, an observation quantity extraction module and a correlation peak ternary detection and spoofing regeneration countermeasure against spoofing module.

[0095] The software running on the digital signal processing chip comprises an attitude and position auxiliary detection and anti-spoofing module, a PVT solution module, an integrity monitoring module and a self-checking module.

[0096] The anti-interference module comprises multi-stage Wiener filtering, optimal anti-interference weight vector calculation and weighted summation processing of array signal vectors.

[0097] The navigation signal processing comprises capture, tracking, data demodulation, TIXX and observation quantity extraction of satellite signals.

[0098] The navigation information processing comprises PVT solution, integrity monitoring and self-checking.

[0099] The anti-spoofing processing comprises correlation peak ternary detection, attitude and position auxiliary detection and spoofing regeneration countermeasure.

[0100] The anti-interference processing, navigation signal processing, correlation peak ternary detection, and deception regeneration for fire deception processing are implemented using VHDL, while the remaining processing is implemented using C.

[0101] According to the present invention, the device is rectangular;

[0102] The structural components of the equipment are made of 5A06 aluminum alloy sheet and assembled using screws.

[0103] The heating elements of the equipment are fitted with GP5000 thermal pads, and thermal protrusions are set at corresponding positions on the bottom of the equipment housing;

[0104] The heat dissipation path of the equipment is: components → thermal pad → housing → aircraft;

[0105] The design parameters for the power supply, power consumption, interface, dimensions and weight of the device are shown in Table 1.

[0106] Table 1 Design parameters for adding anti-interference and anti-spoofing equipment to civil aviation satellite navigation systems

[0107]

[0108] This invention addresses the gap in anti-interference and anti-spoofing equipment for civil aviation satellite navigation. The hardware platform for this equipment is designed as a parallel processing and scalable platform featuring a dual-frequency, 8-channel low-noise RF front-end, scalable FPGA+DSP heterogeneous architecture, and modular interfaces. The software architecture is a layered, modular architecture where the business layer processing is independent of the hardware and the interface layer supports standard protocols. The external structure is an airworthiness compliant structure with a low-profile streamlined profile, no protruding structures, lightweight weather-resistant aluminum alloy materials, and resistance to shock and vibration. It supports multi-frequency, multi-mode, and multi-channel signal processing, cross-platform porting, expansion, and integration.

[0109] The present invention will be described in more detail below through embodiments.

[0110] Example 1:

[0111] like Figure 1 As shown, this embodiment proposes an anti-interference and anti-spoofing method for civil aviation satellite navigation. By constructing a multi-beam pointing and multi-level Wiener filtering anti-interference method, along with correlation peak ternary detection, attitude and position auxiliary detection, and spoofing regeneration methods to combat fire spoofing, it meets the safety requirements of civil aviation satellite navigation applications. The specific process is as follows:

[0112] 1) Constructing a multi-beam pointing, multi-stage Wiener filtering anti-interference method:

[0113] Multi-beam pointing anti-jamming is modeled as a minimum variance distortionless response (MVDR) constrained optimization model:

[0114] ;

[0115] wherein, is the array signal vector is the covariance matrix of is the steering vector in the desired satellite signal direction, is the interference rejection weight vector, is the conjugate transpose symbol of a vector or matrix;

[0116] The reason why the multi-beam pointing interference rejection method is superior to the adaptive nulling interference rejection method is that the former restricts the gain of the satellite signal coming direction , which can ensure the suppression of interference and high-quality reception of satellite signals; the latter restricts the first element of the weight vector to be 1, which only ensures the suppression of interference.

[0117] The optimal interference rejection weight vector of the above constraint optimization problem is:

[0118] ;

[0119] wherein, is the unit matrix, is the interference steering vector matrix, is the projection matrix of the noise subspace, is the inverse symbol of a matrix;

[0120] The projection matrix can be obtained by multi-stage Wiener filtering, and the corresponding initialization and iteration process is as follows:

[0121] Initialization: , ;

[0122] Iteration times: ;

[0123] ;

[0124] ;

[0125] ;

[0126] ;

[0127] Take the first large values corresponding to to form the projection matrix of the noise subspace , wherein is the number of interferences, is the dimension of the vector, , As the initial value for iteration, For vectors The first element, For the interference subspace of the first One orthogonal basis vector, For mathematical expectation operators, the symbol It is a conjugate operator. For modulo operator, This is the conjugate transpose operator. , The first , The expected signal for the next iteration. , The first , The input vector for the next iteration. For the first The mean square value of the desired signal;

[0128] Therefore, the optimal anti-interference weight vector is:

[0129] ;

[0130] Use the optimal anti-interference weight vector to adjust the array signal vector Weighted summation is performed to suppress interference and obtain the satellite signal with good reception quality (i.e., high signal-to-noise ratio).

[0131] 2) Related peak ternary detection, attitude and position auxiliary detection, and deception regeneration methods for fire protection deception:

[0132] The presence of deception is detected by using a three-element detection method for relevant peaks and attitude position-assisted detection. If deception is found, the deception in the captured signal is suppressed by a deception regeneration cancellation method, thereby purifying the satellite signal.

[0133] (1) Ternary detection method for related peaks:

[0134] The spreading code for the primary public service signal in civil aviation is a short-period spreading code, which has the characteristics of a sharp autocorrelation function and a flat cross-correlation function; based on this, the three-element correlation peak detection method is constructed with the following three-element hypothesis:

[0135] H0: At the current carrier Doppler frequency shift-spreading code phase search unit, there is no desired satellite signal;

[0136] H1: At the current carrier Doppler frequency shift-spreading code phase search unit, only the satellite signal is expected;

[0137] H2: At the current carrier Doppler frequency shift-spreading code phase search unit, the expected satellite signal and deception;

[0138] The test statistic obeys a central chi-square distribution when the H0 hypothesis is true; the test statistic obeys a non-central chi-square distribution when the H1, H2 hypothesis is true;

[0139] According to the probability distribution to which the test statistic obeys, the rejection region critical point at the significance level is determined. The significance level is usually taken as 0.05, 0.01, 0.005.

[0140] After anti-interference, the captured signal is correlated with the local spread spectrum code; in the (carrier Doppler frequency shift, spread spectrum code phase) two-dimensional search space, if there is no correlation peak greater than the critical point, it is determined that there is no expected satellite signal, and the acquisition continues; if there is only one correlation peak greater than the critical point, it is determined that there is only an expected satellite signal and no deception, and the tracking phase is directly entered; if there are multiple correlation peaks greater than the critical point, it is determined that there is an expected satellite signal and deception, and the deception regeneration cancellation phase is entered;

[0141] (2) Attitude and position auxiliary detection method:

[0142] If a civil aviation has an inertial navigation system or other navigation system that can provide attitude and position information, the carrier phase double difference method based on attitude and position information auxiliary can be used for deception detection;

[0143] The carrier phase double difference method based on attitude and position information auxiliary fully utilizes the differences between deception and satellite signals in carrier phase single difference and double difference observations to achieve deception detection. The differences between deception and satellite signals in carrier phase single difference and double difference observations are as follows.

[0144] Each deception is transmitted via a pair of repeater antennas, and the angles of arrival at the satellite navigation equipment are exactly the same. Therefore, the carrier phase single difference observations of each deception fluctuate around a constant, and the double difference observations of each deception fluctuate around zero. Each satellite signal is transmitted via different satellite antennas, and the angles of arrival at the satellite navigation equipment are different. Therefore, the carrier phase single difference and double difference observations of different satellite signals are related to satellite motion, integer ambiguity, and baseline vector, and are different for different satellites.

[0145] According to this, the deception detection process of the attitude and position auxiliary detection method is as follows:

[0146] First, determine the acceptable false alarm rate, and solve the detection threshold corresponding to the false alarm rate The solving formula is as follows:

[0147] ;

[0148] In the formula, is the false alarm rate, The probability cumulative distribution function corresponding to the carrier-phase double-difference observation noise distribution function of the satellite signal is defined as follows:

[0149] ;

[0150] In the formula, The variance of carrier phase observation noise;

[0151] Then, using attitude and position information, the carrier phase double difference prediction values ​​for all visible satellites are calculated, with the largest carrier phase double difference prediction value denoted as... ;

[0152] Finally, based on the carrier phase double difference observations and The decision is made based on whether the difference between the carrier phase double difference observation and the predicted value exceeds the detection threshold. That is, if the difference between the carrier phase double difference observation and the predicted value does not exceed the detection threshold, it is determined that only satellite signal is expected and there is no deception, and the process directly enters the tracking stage. If the difference between the carrier phase double difference observation and the predicted value exceeds the detection threshold, it is determined that there is deception, and the process enters the deception regeneration and cancellation stage.

[0153] (3) Deceptive regeneration cancellation method:

[0154] The spreading codes of the primary public service signals for civil aviation are publicly available, and their generation methods can be found in the space signal interface control documents (ICD) of each satellite navigation system; accordingly, the deception regeneration cancellation method suppresses deception in the captured signal after anti-interference according to the following process;

[0155] First, the spoofing in the currently captured signal is tracked to obtain the amplitude and phase estimates of the spoofing. Then, based on the amplitude and phase estimates of the spoofing and the spreading code of the spoofing generated locally according to ICD, the regenerated spoofing is obtained. Subsequently, the regenerated spoofing is subtracted from the captured signal after anti-interference to achieve spoofing cancellation. Finally, after all spoofing is cancelled and the satellite signal is purified, it is transferred to the tracking unit.

[0156] This embodiment provides a civil aviation satellite navigation anti-interference and anti-spoofing device, such as... Figure 2 As shown, it mainly consists of an array antenna, radio frequency channel, digital processing unit, power supply unit, interface unit, etc., specifically including:

[0157] 1) Hardware Design:

[0158] Considering that the main satellite navigation signals used in civil aviation are BDS B1C, B2a, and GPS L1C / A, and that BDS B1C and GPS L1C / A have the same carrier frequency and overlapping signal frequency bands;

[0159] The array antenna mainly consists of 4 B1C frequency band antenna arrays, 4 B2a frequency band antenna arrays, a feeding network, an array surface, etc., wherein the 4 B1C frequency band antenna arrays simultaneously receive B1C and L1C / A satellite signals, interference and deception, and the 4 B2a frequency band antenna arrays receive B2a satellite signals, interference and deception;

[0160] The radio frequency channel mainly consists of 4 B1C frequency band down-conversion units and 4 B2a frequency band down-conversion units, wherein the 4 B1C frequency band down-conversion units filter, frequency-convert, amplify, etc. B1C and L1C / A satellite signals, interference and deception, and the 4 B2a frequency band down-conversion units filter, frequency-convert, amplify, etc. B2a satellite signals, interference and deception;

[0161] The digital processing unit mainly consists of a field programmable gate array (FPGA) chip and a digital signal processing (DSP) chip, wherein the FPGA performs multi-beam interference rejection, navigation signal processing, correlation peak ternary detection and deception regeneration countermeasure, etc. on 8 digital intermediate frequency signals; and the DSP performs navigation information processing, attitude and position auxiliary detection and deception prevention, etc.

[0162] 2) Software design:

[0163] The software running on the FPGA and DSP chips mainly consists of interference rejection processing, navigation signal processing, navigation information processing and deception prevention processing software, as shown in FIG. 2. Figure 3

[0164] The interference rejection processing mainly includes multi-stage Wiener filtering (to obtain a projection matrix of a noise subspace), optimal interference rejection weight vector calculation, weighted summation of array signal vectors, etc.; the navigation signal processing mainly includes satellite signal acquisition, tracking, data demodulation, TIXX, observation quantity extraction, etc.; the navigation information processing mainly includes PVT solution and integrity monitoring, etc.; and the deception prevention processing mainly includes correlation peak ternary detection, attitude and position auxiliary detection, deception regeneration countermeasure, etc.

[0165] The interference rejection processing, navigation signal processing, correlation peak ternary detection and deception regeneration countermeasure processing are implemented by using VHDL language, and the rest of the processing is implemented by using C language.

[0166] 3) Appearance structure design:

[0167] In view of the requirement of adding equipment to civil aviation aircraft, the structural members of the civil aviation satellite navigation interference rejection and deception prevention equipment are processed from 5A06 aluminum alloy plates and combined into shape by screws; the heat generating components are installed with GP5000 heat conducting pads, and there are heat conducting bosses on the corresponding positions at the bottom of the shell, and the heat dissipation path is component → heat conducting pad → shell → aircraft; the appearance structure of the civil aviation satellite navigation interference rejection and deception prevention equipment is shown in FIG. 3.​Figure 4 (positive (a), left (b), c, d, view (d)) as shown;

[0168] 4) Other designs:

[0169] The power supply, power consumption, interface, size and weight of the civil aviation satellite navigation anti-interference and deception prevention equipment are shown in Table 1.

[0170] Table 1: Civil aviation satellite navigation anti-interference and deception prevention equipment installation design parameters

[0171]

[0172] The civil aviation satellite navigation anti-interference and deception prevention method provided by the embodiments of the present application has the advantages of being suitable for multiple types of interference, having strong anti-interference ability, and being strong in engineering practicability, and the like.

[0173] The above has described the embodiments of the present application, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes are obvious to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A civil aviation satellite navigation anti-jamming and anti-deception method, characterized in that, The method comprises the following steps: By constructing a multi-beam pointing and multi-stage Wiener filtering anti-jamming method, an optimal anti-jamming weight vector under the maximum output signal-to-interference-and-noise ratio is solved, so as to maximize the interference suppression degree and minimize the loss of satellite signal receiving signal-to-noise ratio. By using a correlation peak ternary detection method and a position and attitude auxiliary detection method, it is detected whether there is deception in the captured signal after anti-jamming; if there is deception, the deception in the captured signal is suppressed by using a deception regeneration cancellation method, so as to realize satellite signal purification. By constructing a multi-beam pointing and multi-stage Wiener filtering anti-jamming method, an optimal anti-jamming weight vector under the maximum output signal-to-interference-and-noise ratio is solved, so as to maximize the interference suppression degree and minimize the loss of satellite signal receiving signal-to-noise ratio, which comprises the following steps: A multi-beam pointing anti-jamming model is constructed, and the optimal anti-jamming weight vector under the maximum output signal-to-interference-and-noise ratio is the projection of the steering vector in the expected satellite signal direction on the noise subspace; The projection matrix of the noise subspace is obtained by using multi-stage Wiener filtering; Based on the projection matrix, the optimal anti-jamming weight vector of the anti-jamming model is solved; The array signal vector of the anti-jamming model is weighted and summed by using the optimal anti-jamming weight vector, so as to minimize the influence of the satellite signal in the array signal vector while maximizing the interference suppression degree.

2. The method of claim 1, wherein, The anti-jamming model is a minimum variance distortionless response constraint optimization model, and the expression of the constraint optimization model is as follows: ； wherein is a covariance matrix of the array signal vector is a steering vector in the direction of the desired satellite signal, is an anti-jamming weight vector, is the conjugate transpose symbol for vectors or matrices;​ The expression of the optimal anti-jamming weight vector is as follows: ； wherein is an optimal interference rejection weight vector, is an identity matrix, is an interference steering vector matrix, is a projection matrix onto the noise subspace, is an inverse symbol of a matrix, is a number of interferences, is a dimension of a vector; The projection matrix of the noise subspace is obtained by using multi-stage Wiener filtering, and the corresponding initialization and iteration process is as follows: Initialization: , ; iterations subsequent: ; ； ； ； ； Take middle front corresponding to projection matrix constituting noise subspace ; wherein , is an iteration initial value, is a vector of first elements, is a first orthonormal basis vector of the interference subspace, is a second orthonormal basis vector of the interference subspace, is an expectation operator, the symbol is a conjugate operator, is a modulo operator, is a conjugate transpose operator, , are the desired signals of the , th iteration, , are the input vectors of the , th iteration, is the mean square value of the th desired signal.

3. The method of claim 1, wherein, The correlation peak ternary detection method comprises the following steps: A ternary hypothesis of H0 (no expected satellite signal), H1 (only expected satellite signal) and H2 (expected satellite signal and deception) is proposed, a test statistic and a probability distribution to which the test statistic conforms are determined, and a significance level is given; According to the probability distribution to which the test statistic conforms, the critical point of the rejection region under the significance level is determined; The captured signal after anti-jamming is correlated with a local spreading code; In a two-dimensional search space of carrier Doppler frequency shift and spreading code phase, if there is no correlation peak value greater than the critical point, it is determined that there is no expected satellite signal, and the acquisition continues; If there is only one correlation peak value greater than the critical point, it is determined that there is only expected satellite signal and no deception, and the tracking stage is directly entered; If there are multiple correlation peak values greater than the critical point, it is determined that there is expected satellite signal and deception, and the deception regeneration cancellation stage is entered; The test statistic conforms to a centralized chi-square distribution when the H0 hypothesis is true; the test statistic conforms to a non-centralized chi-square distribution when the H1 and H2 hypotheses are true; The position and attitude auxiliary detection method comprises the following steps: An acceptable false alarm rate is determined, and a detection threshold corresponding to the false alarm rate is solved; The carrier phase double difference prediction value of all visible satellites is calculated by using the attitude and position information, wherein the maximum carrier phase double difference prediction value is recorded as ; According to whether the difference between the carrier phase double difference observation value and the exceeds a detection threshold, that is, if the difference between the carrier phase double difference observation value and the does not exceed the detection threshold, it is determined that only satellite signals are expected and there is no spoofing, and directly enters the tracking stage; if the difference between the carrier phase double difference observation value and the exceeds the detection threshold, it is determined that spoofing exists, and enters the spoofing regeneration cancellation stage. The formula for solving the detection threshold is as follows: ； wherein, is a detection threshold, is a false alarm rate, is a probability cumulative distribution function corresponding to a carrier phase double difference observation noise distribution function of the satellite signals; The expression of the probability cumulative distribution function is as follows: ； wherein is the carrier phase observation noise variance.

4. The method of claim 3, wherein, The deception in the captured signal after anti-jamming is suppressed by using a deception regeneration cancellation method, so as to realize satellite signal purification, which comprises the following steps: The deception in the currently captured signal is tracked to obtain an amplitude estimation value and a phase estimation value of the deception. According to the amplitude estimation value, the phase estimation value, and the local generated spoofed spread spectrum code according to the interface control file, a regenerated spoofing is obtained; The regenerated spoofing is subtracted from the captured signal after the anti-interference, and the satellite signal is purified and then input into a tracking unit.

5. Civil aviation satellite navigation anti-jamming and anti-spoofing device for use in the method according to any one of claims 1-4, characterized in that, It comprises: An array antenna comprising four B1C frequency band antenna array elements, four B2a frequency band antenna array elements, a feed network, and an array surface; An RF channel comprising four B1C frequency band down-conversion units and four B2a frequency band down-conversion units, for filtering, frequency conversion, and amplification processing of satellite signals and / or interference and / or spoofing received by the four B1C frequency band antenna array elements and the four B2a frequency band antenna array elements to obtain eight analog signals; A digital processing unit connected to the output of the RF channel, for converting the eight analog signals transmitted by the RF channel into eight digital intermediate frequency signals, and performing multi-beam anti-interference, navigation signal processing, navigation information processing, and anti-spoofing processing on the eight digital intermediate frequency signals; An interface unit comprising an RF interface, a data interface, and a power supply interface, the RF interface being used for RF input and feed output, the data interface being used for data transmission and information injection, and the power supply interface being used for external power supply input and isolation processing; A power supply unit for converting an external power supply voltage into voltages required by the array antenna, the RF channel, and the digital processing unit.

6. The apparatus of claim 5, wherein, The input end of each B1C frequency band down-conversion unit is connected to the output of one B1C frequency band antenna array element, and the input end of each B2a frequency band down-conversion unit is connected to the output of one B2a frequency band antenna array element; The four B1C frequency band down-conversion units and the four B2a frequency band down-conversion units are used for filtering, frequency conversion, and amplification processing of satellite signals and / or interference and / or spoofing received by the four B1C frequency band antenna array elements and the four B2a frequency band antenna array elements, respectively, to obtain eight analog intermediate frequency signals.

7. The apparatus of claim 5, wherein, The digital processing unit comprises eight analog-to-digital converters, a field programmable gate array chip, and a digital signal processing chip; The input end of each analog-to-digital converter is connected to the output end of one B1C frequency band down-conversion unit or one B2a frequency band down-conversion unit, and the output end outputs a digital intermediate frequency signal. The field programmable gate array chip performs multi-beam anti-interference, navigation signal processing, correlation peak triad detection, and spoofing regeneration counter-spoofing processing on the eight digital intermediate frequency signals. The digital signal processing chip performs navigation information processing and attitude and position auxiliary detection anti-spoofing processing.

8. The apparatus of claim 7, wherein, The software running on the field programmable gate array chip comprises an anti-interference module, a capture module, a tracking module, a data demodulation module, a TIXX module, an observation quantity extraction module, and a correlation peak triad detection and spoofing regeneration counter-spoofing module; The software running on the digital signal processing chip comprises an attitude and position auxiliary detection anti-spoofing module, a PVT solution module, an integrity monitoring module, and a self-checking module; The anti-interference module comprises multi-stage Wiener filtering, optimal anti-interference weight vector calculation, and weighted summation processing on array signal vectors. The navigation signal processing includes satellite signal acquisition, tracking, data demodulation, TIXX and observation extraction; The navigation information processing includes PVT solution, integrity monitoring and self-checking; The anti-spoofing processing includes correlation peak ternary detection, attitude position auxiliary detection and spoofing regeneration cancellation; The anti-interference module, navigation signal processing, correlation peak ternary detection and spoofing regeneration cancellation are realized by VHDL language, and the rest of the processing is realized by C language.

9. The apparatus of claim 5, wherein, The device is a cuboid; The structural member of the device is processed from 5A06 aluminum alloy plate and is combined into shape by screw mode; The heat generating components of the device are installed with GP5000 heat conducting pads, and heat conducting bosses are arranged at the corresponding positions of the bottom of the shell of the device; The heat dissipation path of the device is component -> heat conducting pad -> shell -> airplane; The design parameters of the power supply, power consumption, interface, outline size and weight of the device are: 。

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