GNSS-based passive radar target velocity estimation method based on multi-satellite fusion

Abstract

The application discloses a GNSS external source radar moving target velocity estimation method based on multi-satellite fusion. The method comprises the following steps: calculating the three-dimensional positions and velocities of a receiver and satellites based on direct wave data of at least three GNSS satellites received by the GNSS external source radar receiver; calculating the bistatic range delay between each satellite and a moving target and the target echo Doppler frequency observation value corresponding to each satellite based on the echo information of the moving target received by the receiver detection channel; calculating the three-dimensional position of the moving target based on the bistatic range delay between each satellite and the moving target and the three-dimensional positions of the receiver and the satellites; calculating the three-dimensional velocity of the moving target based on the target echo Doppler frequency observation value corresponding to each satellite, the three-dimensional position of the moving target, and the three-dimensional positions and velocities of each satellite and the receiver; and performing error analysis on the three-dimensional velocity of the moving target to obtain an error analysis result. The application can accurately estimate the velocity of the moving target in the three-dimensional space.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of radar detection, in particular to a GNSS external radiation source radar moving target velocity estimation method based on multi-satellite fusion. BACKGROUND

[0002] External radiation source radar is a dual / multi-base radar system that utilizes existing electromagnetic signals in space to detect targets by receiving and processing echo signals reflected by targets. The opportunity illumination sources of external radiation source radar can be divided into ground-based radiation sources and space-based radiation sources. In recent years, with the rapid development of satellite technology, the number of space-based radiation sources has increased significantly. Space-based radiation signals usually have advantages such as wide coverage and rich data sources, making external radiation source radar technology based on space-based radiation sources gradually become a research hotspot.

[0003] In related technologies, when using satellite GNSS external radiation source radar to detect moving targets, single satellite data or a method based on azimuth angle measurement is mainly used for detection. However, the detection results obtained by using the above methods not only have large distance positioning errors, but also the azimuth resolution of the system is inversely proportional to the target distance, which leads to fluctuations in detection accuracy with changes in target position. Therefore, both methods cannot accurately capture target velocity information.

[0004] Therefore, there is an urgent need for a GNSS external radiation source radar moving target velocity estimation method based on multi-satellite fusion to solve the above problems. SUMMARY

[0005] The present application provides a GNSS external radiation source radar moving target velocity estimation method based on multi-satellite fusion, which can accurately estimate the velocity of a moving target in three-dimensional space. The technical solution is as follows:

[0006] In a first aspect, the present application provides a GNSS external radiation source radar moving target velocity estimation method based on multi-satellite fusion, which comprises:

[0007] Based on the direct wave data of at least three GNSS satellites received by the GNSS external radiation source radar receiver, the three-dimensional positions and velocities of the receiver and each satellite are calculated; each satellite can detect a moving target to be estimated;

[0008] Based on the moving target echo information received by the receiver detection channel, the bistatic range delay between each satellite and the moving target is calculated, as well as the target echo Doppler frequency observation value corresponding to each satellite;

[0009] Based on the bistatic range delay between each satellite and the moving target, and the three-dimensional positions of the receiver and each satellite, the three-dimensional position of the moving target is calculated;

[0010] calculating the three-dimensional velocity of the moving target based on the target echo Doppler frequency observation value corresponding to each satellite, the three-dimensional position of the moving target, and the three-dimensional position and velocity of each satellite and the receiver;

[0011] performing error analysis on the three-dimensional velocity of the moving target to obtain an error analysis result.

[0012] In a second aspect, the embodiments of the present application further provide a GNSS external source radar moving target velocity estimation device based on multi-satellite fusion, the device comprising:

[0013] a first calculation unit configured to calculate the three-dimensional position and velocity of each satellite and the receiver based on direct wave data of at least three GNSS satellites received by a GNSS external source radar receiver; each satellite can detect a moving target to be estimated;

[0014] a second calculation unit configured to calculate the bistatic range delay between each satellite and the moving target and the target echo Doppler frequency observation value corresponding to each satellite based on moving target echo information received by a detection channel of the receiver;

[0015] a third calculation unit configured to calculate the three-dimensional position of the moving target based on the bistatic range delay between each satellite and the moving target and the three-dimensional position of each satellite and the receiver;

[0016] a fourth calculation unit configured to calculate the three-dimensional velocity of the moving target based on the target echo Doppler frequency observation value corresponding to each satellite, the three-dimensional position of the moving target, and the three-dimensional position and velocity of each satellite and the receiver;

[0017] an analysis unit configured to perform error analysis on the three-dimensional velocity of the moving target to obtain an error analysis result.

[0018] In a third aspect, the embodiments of the present application further provide an electronic device comprising a memory and a processor, the memory storing a computer program, and the processor executing the computer program to implement the method described in any of the embodiments of the present application.

[0019] In a fourth aspect, the embodiments of the present application further provide a computer readable storage medium storing a computer program, and the computer program, when executed in a computer, causes the computer to execute the method described in any of the embodiments of the present application.

[0020] In a fifth aspect, the embodiments of the present application further provide a computer program product comprising a computer program, and the computer program, when executed by a processor, implements the steps of the method described above.

[0021] The embodiment of the present application provides a GNSS external source radar moving target velocity estimation method based on multi-satellite fusion. The method utilizes the advantages of rich GNSS satellite resources, and adopts a detection system composed of at least three satellites and an external source radar receiver to estimate the three-dimensional velocity of a moving target. First, the three-dimensional positions and velocities of the receiver and the satellites are calculated based on the direct wave data received by the receiver. Then, the Doppler frequency measurement value and the three-dimensional position of the moving target are calculated based on the moving target echo information received by the receiver detection channel. Then, the three-dimensional velocity of the moving target is calculated based on the target echo Doppler frequency observation value corresponding to each satellite, the three-dimensional position of the moving target, and the three-dimensional positions and velocities of the satellites and the receiver. Since the application utilizes the data of multiple satellites, the information acquisition dimension of the system can be improved, and the velocity of the moving target in the three-dimensional space can be accurately estimated. In addition, the application also analyzes the factors affecting the accuracy of the three-dimensional velocity estimation of the moving target, and obtains the error of the velocity estimation. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor.

[0023] Figure 1 It is a flow chart of a GNSS external source radar moving target velocity estimation method based on multi-satellite fusion provided by an embodiment of the present application.

[0024] Figure 2 It is a structural diagram of a GNSS external source radar moving target velocity estimation device based on multi-satellite fusion provided by an embodiment of the present application.

[0025] Figure 3 It is a hardware architecture diagram of a computer device provided by an embodiment of the present application.

[0026] Figure 4 It is a schematic diagram of an external source radar detection system provided by an embodiment of the present application.

[0027] Figure 5 It is a comparison curve of the target three-dimensional velocity estimation result and the theoretical value provided by an embodiment of the present application.

[0028] Figure 6 It is a comparison curve of the standard deviation theoretical value of the three-axis direction velocity error and the measured standard deviation provided by an embodiment of the present application. DETAILED DESCRIPTION

[0029] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0030] The specific implementation of the above concept will be described below.

[0031] Please refer to Figure 1 The embodiments of the present application provide a GNSS external source radar moving target velocity estimation method based on multi-satellite fusion, which comprises the following steps.

[0032] In step 100, the direct wave data of at least three GNSS satellites received by a GNSS external source radar receiver is used to calculate the three-dimensional positions and velocities of the receiver and the satellites; each satellite can detect a moving target to be estimated;

[0033] In step 102, the bistatic range delay between each satellite and the moving target and the target echo Doppler frequency observation value corresponding to each satellite are calculated based on the moving target echo information received by the receiver detection channel;

[0034] In step 104, the three-dimensional position of the moving target is calculated based on the bistatic range delay between each satellite and the moving target and the three-dimensional positions of the receiver and the satellites;

[0035] In step 106, the three-dimensional velocity of the moving target is calculated based on the target echo Doppler frequency observation value corresponding to each satellite, the three-dimensional position of the moving target, and the three-dimensional positions and velocities of the satellites and the receiver;

[0036] In step 108, the three-dimensional velocity of the moving target is subjected to error analysis to obtain an error analysis result.

[0037] In this embodiment, the advantages of rich GNSS satellite resources are utilized, and a detection system composed of at least three satellites and an external radiation source radar receiver is used to estimate the three-dimensional velocity of a moving target. First, the three-dimensional positions and velocities of the receiver and each satellite are calculated based on the direct wave data received by the receiver. Then, the Doppler frequency measurement value and the three-dimensional position of the moving target are calculated based on the echo information of the moving target received by the receiver detection channel. Then, the three-dimensional velocity of the moving target is calculated based on the target echo Doppler frequency observation value corresponding to each satellite, the three-dimensional position of the moving target, and the three-dimensional positions and velocities of each satellite and the receiver. Since the application utilizes the data of multiple satellites, the information acquisition dimension of the system can be improved, and the velocity of the moving target in the three-dimensional space can be accurately estimated. In addition, the factors affecting the accuracy of the three-dimensional velocity estimation of the moving target are analyzed, and the error of the velocity estimation is obtained.

[0038] The execution mode of each step is described below. Figure 1 The execution mode of each step is described below.

[0039] First, for steps 100, 102 and 104:

[0040] Each GNSS satellite can detect the moving target to be estimated, and at each moment, the receiver can receive the direct wave and echo information of the moving target reflected by the satellite based on the direct channel and the detection channel. Then, the real-time three-dimensional position and velocity of the receiver and each satellite are calculated based on the direct wave; and the bistatic range delay between each satellite and the moving target, and the target echo Doppler frequency observation value corresponding to each satellite are calculated based on the real-time echo information of the moving target.

[0041] In addition, after calculating the real-time three-dimensional position and velocity of the receiver and each satellite, the calculated coordinates need to be converted to the Earth-Centered Earth-Fixed coordinate system. At the same time, the time and frequency synchronization between the receiver and the satellite is completed using the obtained information, and the system preprocessing is realized.

[0042] Finally, the real-time three-dimensional position of the moving target is calculated based on the calculated bistatic range delay between each satellite and the moving target, and the three-dimensional position of the receiver and each satellite.

[0043] It should be noted that the calculation method used in step 104 is the existing method for solving nonlinear equations, which will not be described here.

[0044] Second, for step 106, the three-dimensional velocity of the moving target is calculated based on the target echo Doppler frequency observation value corresponding to each satellite, the three-dimensional position of the moving target, and the three-dimensional positions and velocities of each satellite and the receiver, including:

[0045] A1, based on the three-dimensional positions of each satellite, receiver and moving target, respectively calculating the unit vector of the moving target to the direction of each satellite and the unit vector of the moving target to the direction of the receiver;

[0046] A2, based on the target echo Doppler frequency observation value corresponding to each satellite, the unit vector of the moving target to the direction of each satellite, the unit vector of the moving target to the direction of the receiver, the speed of the receiver and each satellite, the signal carrier wavelength and the target echo Doppler frequency observation noise corresponding to each satellite, constructing an initial equation group containing the three-dimensional velocity of the moving target;

[0047] A3, solving the initial equation group to obtain the three-dimensional velocity of the moving target.

[0048] As shown in Figure 4 , it is a schematic diagram of a detection system composed of each satellite, radar receiver and moving target. The following will take this diagram as an example to detail the calculation process of steps A1-A3.

[0049] First, for step A1, through steps 100-104, the real-time positions of each satellite, radar receiver and moving target can be calculated. Under the premise that the positions of each device are known, the calculation method of the unit vector of the moving target to the direction of each satellite and the unit vector of the moving target to the direction of the receiver is the existing method, which will not be repeated here.

[0050] Then, for step A2, first list the calculation formula of the Doppler frequency observation value, that is, the Doppler frequency observation value of the target reflection of the GNSS signal in the detection channel is equal to the derivative of the bistatic range delay between the satellite and the moving target with respect to time and the ratio of the carrier wavelength:

[0051]

[0052] In the formula, f d (t) represents the target echo Doppler frequency observation value of the satellite at time t; R(t) represents the bistatic range delay between the satellite and the moving target at time t.

[0053] Since there are multiple GNSS satellites in the application, the initial equation group related to the target Doppler frequency observation value can be obtained according to formula (1), and the expression of the initial equation group is as follows:

[0054]

[0055] In the formula, f di represents the target echo Doppler frequency observation value corresponding to the i-th satellite, i=1,2……m, m is the number of satellites, m is not less than 3; λ represents the signal carrier wavelength; v si represents the velocity vector of the i-th satellite; v r represents the velocity vector of the receiver; utsi u tr v t n fi

[0056] In the above equation set, except for the observation noise n fi , the equation set only remains three unknown variables of the target's three-dimensional velocity coordinates v t = [v tx , v ty , v tz ]. The observation noise n fi can be determined according to the actual detection scene, so that only the above initial equation set needs to be solved to obtain the three-dimensional velocity of the moving target.

[0057] Finally, for step A3, it includes:

[0058] B1, the initial equation set is transformed and arranged to obtain the apparent Doppler frequency observation equation set;

[0059] B2, based on the relationship between the bistatic range delay between each satellite and the moving target and the unit vector of the moving target to the direction of each satellite and the unit vector of the moving target to the receiver, the apparent Doppler frequency observation equation set is simplified to obtain the simplified apparent Doppler frequency observation equation set;

[0060] B3, based on the vector definition, the simplified apparent Doppler frequency observation equation set is converted into an apparent Doppler frequency observation matrix;

[0061] B4, based on the least square method, the apparent Doppler frequency observation matrix is solved to obtain the three-dimensional velocity of the moving target.

[0062] First, for step B1, according to the obtained motion information of each GNSS satellite and the receiver, the relative motion of each GNSS satellite and the receiver to the Doppler frequency observation value is first eliminated, at this time the residual Doppler frequency is mainly determined by the target motion and the observation noise. The known satellite speed and receiver speed term in formula (2) is arranged and moved to the left side of the equation, and the following form of apparent Doppler frequency observation equation set is obtained:

[0063]

[0064] Second, for step B2, the apparent Doppler frequency observation value f tdi corresponding to the i-th satellite is defined as:

[0065] ​

[0066] The bistatic range-rate gradient vector between the i-th satellite and the moving target is defined as u i :

[0067] u i =u tsi +u tr

[0068] The expression of the simplified apparent Doppler frequency observation equation of formula (3) is as follows:

[0069]

[0070] It can be seen from formula (4) that the apparent Doppler frequency observation is completely determined by the projection of the target speed on the bistatic range-rate gradient vector and the Doppler frequency observation noise of the system.

[0071] Then, for step B3, the matrix f td composed of the apparent Doppler frequency observations corresponding to each satellite, the matrix U composed of the bistatic range-rate gradient vectors between each satellite and the moving target, and the matrix n f composed of the target echo Doppler frequency observation noise corresponding to each satellite are obtained respectively through vector definition. The definitions of the matrices are as follows:

[0072] Wherein,

[0073] In the formula, f tdi represents the apparent Doppler frequency observation corresponding to the i-th satellite; u i represents the bistatic range-rate gradient vector between the i-th satellite and the moving target, pointing to the bisector direction of the angle β of the bistatic angle, as shown in Figure 4 Each GNSS satellite has a corresponding bistatic range-rate gradient vector, and the corresponding bistatic range change speed of the target along the direction has the maximum value.

[0074] Through the above definitions, the expression of the apparent Doppler frequency observation matrix is as follows:

[0075]

[0076] Finally, for step B4, equation (5) is a linear state observation equation, which does not need to be linearized and processed by the Newton iteration process, so it can be solved by the least square method, and the three-dimensional speed of the moving target is as follows:

[0077] v t =λ(U T U) -1 U T ftd .

[0078] By the above formula, the estimation of the target three-dimensional velocity parameter can be completed.

[0079] Finally, for step 108, it includes:

[0080] predefining a velocity error transfer matrix;

[0081] based on the velocity error transfer matrix, deducing the error transfer relationship between the target three-dimensional velocity estimation error and the Doppler frequency observation noise, and obtaining the variance of the target three-dimensional velocity estimation error;

[0082] based on the relationship between the velocity error transfer matrix and the constant velocity error coefficient, calculating the standard deviation of the target three-dimensional velocity estimation error.

[0083] In this step, the target three-dimensional velocity estimation error caused by the observation noise nfi is defined as δv t = [δv tx , δv ty , δv tz ] T When the observation noise is less than the apparent Doppler frequency observation vector, it can be deduced that:

[0084] δv t = λ(U T U) -1 U T n f

[0085] The target three-dimensional velocity estimation error δv t is irrelevant to the apparent Doppler frequency observation vector f td , but only affected by the observation noise vector n f . It can be deduced that the covariance matrix of the target three-dimensional velocity estimation error is:

[0086]

[0087] wherein, C nf is the covariance matrix of the Doppler frequency observation noise vector n f .

[0088] Assuming that the apparent Doppler frequency observation noises corresponding to different GNSS satellites are independent of each other, and the apparent Doppler frequency observation noises corresponding to these satellites have a consistent power, i.e. Here, I represents an m x m order unit matrix. Substituting into equation (6), the unit matrix I can be eliminated, and the expression of the variance of the target three-dimensional velocity estimation error is:

[0089]

[0090] The velocity error transfer matrix is defined as: Since U points to the angle bisector of bistatic angle β, S reflects the geometry of the system. The variance of Doppler frequency observation error is scaled by error transfer matrix S and transformed into the variance of target three-dimensional velocity estimation error.

[0091] From equation (7), it can be seen that the estimation accuracy of target three-dimensional velocity is mainly determined by the measurement accuracy of Doppler frequency and the geometry relationship among GNSS satellites, receiver and target at the observation moment.

[0092] Taking the square root of the covariance matrix obtained from equation (7), the standard deviation σ vt of target three-dimensional velocity estimation error is obtained, and the expression of standard deviation is:

[0093]

[0094] where,

[0095] In the formula, δv t represents the estimation error of target three-dimensional velocity; var(δv t ) and σ vt represent the variance and standard deviation of δv t , respectively; λ represents the wavelength of signal carrier; σ f represents the standard deviation of system Doppler frequency observation error; S represents the velocity error transfer matrix; U represents the matrix composed of bistatic range gradient vectors between each satellite and moving target; u i represents the bistatic range gradient vector between the i-th satellite and moving target; κ vt represents the constant velocity error coefficient; σ vx , σ vy , σ vz represent the standard deviations of velocity estimation error along x, y, z three-axis directions, respectively.

[0096] From equation (8), it can be seen that the standard deviation σ vt of target three-dimensional velocity estimation error is equal to the result of scaling κ vt after the standard deviation σ f of system Doppler frequency observation error. The constant velocity error coefficient is related to S and is mainly determined by the geometry of GNSS external source radar system, which characterizes the scaling characteristics of GNSS external source radar system to Doppler frequency observation noise. Under certain Doppler frequency observation error conditions, a larger constant velocity error coefficient usually corresponds to a poorer target velocity estimation accuracy.

[0097] To prove the effectiveness of the method of the present application, the inventors built a simulation system as shown in FIG. 1 using MATLAB software, simulated the actual detection system using the simulation method, and performed full-link simulation processing analysis. Figure 4

[0098] In the simulation system simulation, the target was set as a moving airplane, and a total of 4 GNSS satellites were used. The satellite parameters and detection parameters are shown in Table 1, and the three-dimensional position and velocity information of each satellite and the receiver in the Earth-Centered Earth-Fixed coordinate system is shown in Table 2.

[0099] Table 1: Detection system simulation parameters

[0100] Parameter Value Satellite GPS PRN1 L1 signal Signal bandwidth 1.023 MHz Sampling rate 4 MHz Equivalent pulse repetition frequency 1000 Hz Simulation duration 60s

[0101] Table 2: Position and velocity of receiver and each satellite in the Earth-Centered Earth-Fixed coordinate system

[0102]

[0103] In the simulation program, the parameters of the target in the station-centered coordinate system (with the receiver as the origin) and the Earth-Centered Earth-Fixed coordinate system (with the Earth's center as the origin) were set as shown in Table 3, and the parameters were used as the true value of the moving target for comparison with the estimated results calculated using the method of the present application.

[0104] Table 3: Target position and velocity setting in different coordinate systems

[0105]

[0106] In addition, in the simulation, the standard deviation of the Doppler frequency observation noise was set to 20 Hz, and a random error was added to each Doppler measurement value.

[0107] Based on the above parameters, the set moving target was continuously estimated for position and velocity within a continuous observation time of 60 s, and the estimated results were compared with the true values set in the simulation, and the error was analyzed. In the simulation process, first, the target three-dimensional velocity estimation method proposed in the above embodiment was used for parameter estimation, and the target three-dimensional velocity estimation results in the Earth-Centered Earth-Fixed coordinate system and the comparison curve with the theoretical value are shown in FIG. 2. Figure 5 From the figure, it can be seen that the estimated results of the target velocity along the three coordinate axes are in good agreement with the true values, verifying the effectiveness of the target three-dimensional velocity estimation method based on multi-satellite fusion proposed in the present application. Then, the velocity error was estimated, and the velocity estimation error along the x, y, and z axes is shown in FIG. 3. Figure 6 According to the simulation parameters set, the standard deviation of the velocity estimation error along the x, y, and z axes in the Earth-Centered Earth-Fixed coordinate system is σ vx = 5.2 m / s, σ vy ​= 3.6 m / s, σ vz = 4.8 m / s, the standard deviation of the estimated velocity error along the x, y, z three-axis direction is σ vx = 5.2 m / s, σ vy = 3.6 m / s, σ vz = 4.8 m / s. It can be seen that the target velocity estimated by the method has high precision.

[0108] In summary, the measured value is in good agreement with the theoretical value, which verifies the correctness of the three-dimensional velocity estimation error analysis of the target in the geocentric and solid earth coordinate system.

[0109] As shown in Figure 2 , Figure 3 , the embodiment of the application provides a GNSS external source radar moving target velocity estimation device based on multi-satellite fusion. The device embodiment can be realized by software, or realized by hardware or a combination of software and hardware. From the hardware layer, as shown in Figure 2 , it is a hardware architecture diagram of a computing device where the GNSS external source radar moving target velocity estimation device based on multi-satellite fusion provided by the embodiment of the application is located. In addition to the processor, memory, network interface, and non-volatile memory shown in Figure 2 , the computing device where the device in the embodiment is usually also includes other hardware, such as a forwarding chip responsible for processing messages, etc. Taking software implementation as an example, as shown in Figure 3 , as a logically meaningful device, it is formed by the CPU of the computing device where it is located reading the corresponding computer program in the non-volatile memory into the memory for running.

[0110] Please refer to Figure 3 , the embodiment of the application provides a GNSS external source radar moving target velocity estimation device based on multi-satellite fusion, and the device comprises:

[0111] The first calculation unit 300 is configured to calculate the three-dimensional positions and velocities of the receiver and each satellite based on the direct wave data of at least three GNSS satellites received by the GNSS external source radar receiver; and each satellite can detect a moving target to be estimated;

[0112] The second calculation unit 302 is configured to calculate the bistatic range delay between each satellite and the moving target and the target echo Doppler frequency observation value corresponding to each satellite based on the moving target echo information received by the receiver detection channel;

[0113] The third calculation unit 304 is configured to calculate the three-dimensional position of the moving target based on the bistatic range delay between each satellite and the moving target and the three-dimensional positions of the receiver and each satellite;

[0114] The fourth calculation unit 306 is configured to calculate the three-dimensional velocity of the moving target based on the target echo Doppler frequency observation value corresponding to each satellite, the three-dimensional position of the moving target, and the three-dimensional position and velocity of each satellite and the receiver.

[0115] The analysis unit 308 is configured to perform error analysis on the three-dimensional velocity of the moving target to obtain an error analysis result.

[0116] In some embodiments, the fourth calculation unit 306 is configured to perform the following operations:

[0117] Based on the three-dimensional positions of each satellite, the receiver, and the moving target, the unit vector of the moving target to the direction of each satellite and the unit vector of the moving target to the direction of the receiver are calculated respectively;

[0118] Based on the target echo Doppler frequency observation value corresponding to each satellite, the unit vector of the moving target to the direction of each satellite, the unit vector of the moving target to the direction of the receiver, the velocity of the receiver and each satellite, the signal carrier wavelength, and the target echo Doppler frequency observation noise corresponding to each satellite, an initial equation set containing the three-dimensional velocity of the moving target is constructed;

[0119] The initial equation set is solved to obtain the three-dimensional velocity of the moving target.

[0120] In some embodiments, the expression of the initial equation set is as follows:

[0121]

[0122] In the formula, f di represents the target echo Doppler frequency observation value corresponding to the i th satellite, i = 1, 2, …, m, m is the number of satellites, and m is not less than 3; λ represents the signal carrier wavelength; v si represents the velocity vector of the i th satellite; v r represents the velocity vector of the receiver; u tsi represents the unit vector of the moving target to the direction of the i th satellite; u tr represents the unit vector of the moving target to the direction of the receiver; v t represents the velocity vector of the moving target; n fi represents the target echo Doppler frequency observation noise corresponding to the i th satellite.

[0123] In some embodiments, when the fourth calculation unit 306 performs solving the initial equation set to obtain the three-dimensional velocity of the moving target, it is configured to perform the following operations:

[0124] The initial equation set is transformed and arranged to obtain an apparent Doppler frequency observation value equation set;

[0125] Based on the relationship between the bistatic range delay between each satellite and the moving target and the unit vector from the moving target to each satellite and the unit vector from the moving target to the receiver, the apparent Doppler frequency observation equation set is simplified to obtain a simplified apparent Doppler frequency observation equation set;

[0126] Based on the vector definition, the simplified apparent Doppler frequency observation equation set is converted into an apparent Doppler frequency observation observation matrix;

[0127] Based on the least square method, the apparent Doppler frequency observation observation matrix is solved to obtain the three-dimensional velocity of the moving target.

[0128] In some embodiments, the analysis unit 308 is configured to perform the following operations:

[0129] A velocity error transfer matrix is predefined;

[0130] Based on the velocity error transfer matrix, an error transfer relationship between the target three-dimensional velocity estimation error and the Doppler frequency observation noise is derived to obtain the variance of the target three-dimensional velocity estimation error;

[0131] Based on the relationship between the velocity error transfer matrix and the constant velocity error coefficient, the standard deviation of the target three-dimensional velocity estimation error is calculated.

[0132] In some embodiments, the expression of the variance of the target three-dimensional velocity estimation error is:

[0133]

[0134] The expression of the standard deviation of the target three-dimensional velocity estimation error is:

[0135] σ vt =κ vt σ f ,

[0136] In the formula, δv t represents the target three-dimensional velocity estimation error; var(δv t ) and σ vt represent the variance and standard deviation of δv t , respectively; λ represents the signal carrier wavelength; σ f represents the standard deviation of the system Doppler frequency observation error; S represents the velocity error transfer matrix; U represents a matrix composed of the bistatic range gradient vectors between each satellite and the moving target; u i represents the bistatic range gradient vector between the i th satellite and the moving target; κ vt represents the constant velocity error coefficient.

[0137] It should be noted that the above embodiment provides a GNSS external source radar moving target velocity estimation device based on multi-satellite fusion, and only the above functional modules are exemplified, and in actual application, the above functions can be distributed by different functional modules to complete, that is, the internal structure of the device is divided into different functional modules to complete all or part of the functions described above. In addition, the GNSS external source radar moving target velocity estimation device based on multi-satellite fusion provided in the above embodiment and the GNSS external source radar moving target velocity estimation method based on multi-satellite fusion embodiment belong to the same concept, and the specific implementation process is described in the method embodiment, which will not be repeated here.

[0138] Embodiments of the present application also provide a computer device, which refers to Figure 3 The computer device includes a processor and a memory, and the memory stores at least one instruction, at least one program, a code set or an instruction set, and the at least one instruction, at least one program, code set or instruction set is loaded and executed by the processor to implement the GNSS external source radar moving target velocity estimation method based on multi-satellite fusion provided by each method embodiment.

[0139] Embodiments of the present application also provide a computer readable storage medium, which stores at least one instruction, at least one program, a code set or an instruction set, and the at least one instruction, at least one program, code set or instruction set is loaded and executed by the processor to implement the GNSS external source radar moving target velocity estimation method based on multi-satellite fusion provided by each method embodiment.

[0140] Embodiments of the present application also provide a computer program product, which includes a computer program, and the processor of the computer device reads the computer program from the computer readable storage medium, and the processor executes the computer program, so that the computer device executes the GNSS external source radar moving target velocity estimation method based on multi-satellite fusion described in any of the above embodiments.

[0141] For the convenience of description, the above system or device is described as various modules or units respectively described in function. Of course, in the implementation of the present application, the functions of each unit can be implemented in the same or more software and / or hardware.

[0142] Those skilled in the art can clearly understand the application by the description of the above embodiments. The technical solutions of the application can be implemented by means of software and necessary universal hardware platforms. Based on such an understanding, the technical solutions of the application can be embodied in the form of a software product, which can be stored in a storage medium, such as a ROM / RAM, a magnetic disk, or an optical disk, and includes a number of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in various embodiments or some parts of the embodiments of the application.

[0143] Finally, it should be noted that the terms such as first, second, third, and fourth, etc. are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the terms "include", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device. Without more limitations, the element defined by the statement "including a" does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0144] The above description is only the preferred embodiments of the application, and it should be pointed out that those skilled in the art can make some improvements and refinements without departing from the principles of the application, and these improvements and refinements should also be regarded as the protection scope of the application.​​

Claims

1. A GNSS-based E-SR radar moving target velocity estimation method based on multi-satellite fusion, characterized in that, The method comprises: calculating the three-dimensional positions and velocities of the receiver and each satellite based on direct wave data of at least three GNSS satellites received by a GNSS external source radar receiver; each satellite can detect a moving target to be estimated; calculating the bistatic range delay between each satellite and the moving target and the corresponding target echo Doppler frequency observation value of each satellite based on the moving target echo information received by the receiver detection channel; calculating the three-dimensional position of the moving target based on the bistatic range delay between each satellite and the moving target and the three-dimensional positions of the receiver and each satellite; calculating the three-dimensional velocity of the moving target based on the corresponding target echo Doppler frequency observation value of each satellite, the three-dimensional position of the moving target, and the three-dimensional positions and velocities of each satellite and the receiver; performing error analysis on the three-dimensional velocity of the moving target to obtain an error analysis result.

2. The method of claim 1, wherein, The calculation of the three-dimensional velocity of the moving target based on the corresponding target echo Doppler frequency observation value of each satellite, the three-dimensional position of the moving target, and the three-dimensional positions and velocities of each satellite and the receiver comprises: calculating the unit vector of the moving target to the direction of each satellite and the unit vector of the moving target to the direction of the receiver based on the three-dimensional positions of each satellite, the receiver, and the moving target; constructing an initial equation set containing the three-dimensional velocity of the moving target based on the corresponding target echo Doppler frequency observation value of each satellite, the unit vector of the moving target to the direction of each satellite, the unit vector of the moving target to the direction of the receiver, the velocities of the receiver and each satellite, the signal carrier wavelength, and the corresponding target echo Doppler frequency observation noise of each satellite; solving the initial equation set to obtain the three-dimensional velocity of the moving target.

3. The method of claim 2, wherein, The expression of the initial equation set is as follows: In the formula, f di represents the target echo Doppler frequency observation value corresponding to the i th satellite, i = 1, 2 … m, m is the number of satellites, and m is not less than 3; λ represents the signal carrier wavelength; v si represents the velocity vector of the i th satellite; v r represents the velocity vector of the receiver; u tsi represents the unit vector of the moving target to the i th satellite; u tr represents the unit vector of the moving target to the receiver; v t represents the velocity vector of the moving target; n fi represents the target echo Doppler frequency observation noise corresponding to the i th satellite.

4. The method of claim 3, wherein, The solution of the initial equation set to obtain the three-dimensional velocity of the moving target comprises: transforming and arranging the initial equation set to obtain an apparent Doppler frequency observation value equation set; simplifying the apparent Doppler frequency observation value equation set based on the relationship between the bistatic range delay between each satellite and the moving target and the unit vector of the moving target to the direction of each satellite and the unit vector of the moving target to the direction of the receiver to obtain a simplified apparent Doppler frequency observation value equation set; translating the simplified apparent Doppler frequency observation value equation set into an apparent Doppler frequency observation value observation matrix based on vector definition; solving the apparent Doppler frequency observation value observation matrix based on the least square method to obtain the three-dimensional velocity of the moving target.

5. The method of claim 3, wherein, The error analysis on the three-dimensional velocity of the moving target to obtain an error analysis result comprises: predefining a velocity error transfer matrix; deriving the error transfer relationship between the target three-dimensional velocity estimation error and the Doppler frequency observation noise based on the velocity error transfer matrix to obtain the variance of the target three-dimensional velocity estimation error; calculating the standard deviation of the target three-dimensional velocity estimation error based on the relationship between the velocity error transfer matrix and the constant speed error coefficient.

6. The method according to claim 5, wherein the expression of the variance of the target three-dimensional velocity estimation error is The expression of the standard deviation of the target three-dimensional velocity estimation error is: σ vt = κ vt σ f , where δv t represents the target three-dimensional velocity estimation error; var(δv t ) and σ vt represent the variance and standard deviation of δv t , respectively; λ represents the signal carrier wavelength; σ f represents the standard deviation of the system Doppler frequency observation error; S represents the velocity error transfer matrix; U represents a matrix composed of bi-static range gradient vectors between each satellite and the moving target; u i represents the bi-static range gradient vector between the i-th satellite and the moving target; and κ vt represents the constant velocity error coefficient.

7. A GNSS-based E-SMR moving target velocity estimation device based on multi-satellite fusion, characterized in that, The device comprises: A first calculation unit configured to calculate three-dimensional positions and velocities of the receiver and each satellite based on direct wave data of at least three GNSS satellites received by a GNSS external radiation source radar receiver; each satellite can detect a moving target to be estimated; A second calculation unit configured to calculate a bistatic range delay between each satellite and the moving target and a target echo Doppler frequency observation value corresponding to each satellite based on echo information of the moving target received by the receiver detection channel; A third calculation unit configured to calculate a three-dimensional position of the moving target based on the bistatic range delay between each satellite and the moving target and the three-dimensional positions of the receiver and each satellite; A fourth calculation unit configured to calculate a three-dimensional velocity of the moving target based on the target echo Doppler frequency observation value corresponding to each satellite, the three-dimensional position of the moving target, and the three-dimensional positions and velocities of each satellite and the receiver; An analysis unit configured to perform error analysis on the three-dimensional velocity of the moving target to obtain an error analysis result.

8. A computing device comprising a memory and a processor, wherein the memory stores a computer program, and the processor implements the method of any one of claims 1-6 when executing the computer program.

9. A computer readable storage medium having a computer program stored thereon, wherein the computer program, when executed in a computer, causes the computer to perform the method of any one of claims 1-6.

10. A computer program product, characterised in that, The computer program comprises a processor that implements the steps of the method of any one of claims 1-6 when executed.

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