Three-station mixed target positioning method combining in-station / inter-station measurement

Abstract

The invention discloses a three-station mixed target positioning method combining in-station / inter-station measurement, and the method comprises the steps: obtaining the DOA measurement in each radar station, dividing a radar into a reference station and two receiving stations, and obtaining the inter-station TDOA measurement and FDOA measurement of the receiving stations and the reference stations; estimating the X-axis coordinate of the target and the distance from the target to the reference station by using DOA measurement and TDOA measurement; correcting the X-axis coordinate of the target and the distance from the target to the reference station by using FDOA measurement; y-axis and Z-axis coordinates of the target are determined by using the TDOA measurement and correction X-axis coordinates and the distance from the target to the reference station, and three-station target positioning is completed. According to the method, a satellite is used as a radiation source to transmit signals, unmanned aerial vehicles are used as receiving stations to receive the signals, a target is positioned by means of various in-station / inter-station measurement information, and only three unmanned aerial vehicles are needed to serve as the receiving stations, so that target positioning can be achieved. The method has a good engineering application prospect.

Description

Technical Field

[0001] The invention belongs to the technical field of target positioning, and relates to a three-station hybrid target positioning method for combined intra-station / inter-station measurement. Background Art

[0002] High-precision target positioning by multi-station radar is a unique advantage of distributed radar systems. The target positioning capability comes from the difference in the target observation angles of multi-station radars. Under the condition of a given number of radars, the more dispersed the radar observation angles of the target, the higher the system airspace diversity gain can be obtained, and the higher the target positioning accuracy; conversely, if the target is located in the same observation direction of the multi-station radar, it cannot be effectively positioned. Target positioning has broad application prospects in both military and civilian fields: in the military, accurate estimation of the target position provides a strong guarantee for wartime intelligence acquisition, tracking and even the final precision strike; in the civilian field, accurate positioning can provide reliable assistance for communications, rescue, transportation and other livelihood services.

[0003] Target positioning is generally divided into two types: active positioning and passive positioning. Active positioning refers to the radar actively transmitting signals, which are returned to the receiving end after being illuminated by the target, that is, the transmitting signal source is controllable. It is a complete transceiver-receiver system, but the existence of the transmitting source makes the radar concealed and vulnerable to enemy electronic interference; passive positioning radar does not transmit signals, but only receives signals radiated by the target. It has good concealment, but it cannot locate the target when the target radiation intensity is low. The air-space cross-domain radar system uses high-orbit satellites to illuminate the mission area and unmanned aerial vehicles to receive the target. The radiation source is cooperatively controllable. The cost of the enemy interfering with our high-orbit satellite is very high. It combines the respective advantages of active positioning and passive positioning and can be used as a supplement to the positioning type. For the distributed radar target positioning with one send and multiple receive, the time difference of arrival (TDOA) positioning requires at least four receiving stations. In a wartime environment, the number of receiving stations is a very valuable perception resource. It is necessary to study the target positioning problem under a given number of receiving stations. To this end, the present invention studies three-station target positioning and proposes a three-station hybrid target positioning method combining intra-station / inter-station measurements.

[0004] Different from satellite navigation positioning technology, positioning is completed at the user's location. In the radar target positioning problem, the relationship between the radar and the target is a non-cooperative relationship. The premise of positioning is that the target has been detected, and the positioning solution is completed at the central processing center of the receiving end. According to the different stages of signal acquisition, target positioning methods can be divided into direct positioning methods and indirect positioning methods. The direct positioning method refers to directly combining the target signals of multiple receiving stations to directly estimate the target position at the signal level. If multiple radars observe the target at approximately the same angle of view, the target can also be located by using phase information through signal coherence, which significantly improves the positioning accuracy. In the direct positioning method, the target position can be achieved through multidimensional search or optimization relaxation methods, but the multidimensional search method faces the problems of phase ambiguity and large amount of calculation, while the optimization relaxation method requires adjusting parameters and balancing between convex relaxation approximation and positioning accuracy. As the name suggests, the indirect positioning method first extracts indirect measurements from the signal, such as distance, Doppler, angle, etc., and then performs measurement-level positioning on the target based on the extracted measurements. Since the indirect positioning method isolates the positioning process and can obtain a closed-form solution to the target position, this type of method has become the mainstream method of research.

[0005] The premise of target positioning is that the target parameters are identifiable to the current radar system. For the problem of aerial (three-dimensional) target positioning, excluding the pathological observation configuration, TDOA positioning requires at least four stations, and the differential will consume an additional public receiving station. In addition, target positioning is closely related to factors such as the number of radar stations, radar-target geometric configuration, and signal-to-noise ratio (SNR). If the positioning accuracy index requirements are to be met, it is also necessary to optimize the above factors in conjunction with the radar system parameters. The ellipsoid positioning estimator proposed by Chan and Ho is a classic two-stage TDOA positioning method. In the first stage, the reference distance (the distance from the reference radar to the target) and the target position form an augmented parameter vector, and the augmented parameter vector is estimated by linearizing the nonlinear equations. In the second stage, the relationship between the reference distance and the target position is used to update the target positioning result. Furthermore, at the 2004 ISCAS conference, Ho and Parith modified the method into an iterative form, making it suitable for situations where there is a position error in the receiving station. Under the condition that the position error of the receiving station is very small, this method can approximate the Cramer-Rao lower bound of the parameter estimate. When the position error is large, the introduction of nonlinearity will lead to a decrease in positioning accuracy. For this reason, the researchers tried to replace it with the first-order Taylor approximation technique in the second stage, and achieved certain improvements in accuracy. However, this type of method introduces the reference distance into the augmented parameter vector, so at least five receiving stations are required to meet the requirement of parameter identifiability. For this reason, public literature points out that the estimate of the reference distance can be substituted into the augmented parameter vector first to reduce the number of required receiving stations.

[0006] Although the above method can reduce the number of receiving stations for TDOA positioning to a minimum of four stations. However, for real-time reconnaissance and surveillance, the number of receiving stations is a very precious resource. Under permitted conditions, we hope to use as few receiving stations as possible to meet the positioning index requirements, and even reduce the number of stations at the cost of a certain degree of positioning accuracy loss under the condition of meeting the index requirements. In these cases, it will be necessary to study three-station target positioning. If TDOA measurements are used for multi-station target positioning, at least four receiving stations are required. If there are only three receiving stations, the unrecognizable target parameters need to be estimated through other additional measurements.

[0007] To this end, the present invention combines multiple measurement information within / between radar stations, estimates the reference distance and target X-coordinate within the station, and enables the estimation of the remaining target parameters to be achieved through three stations. A three-station hybrid target positioning method combining intra-station / inter-station measurements is proposed, which provides more accurate target position information for applications such as strategy, reconnaissance and guidance. Summary of the invention

[0008] The technical problem solved by the present invention is: to overcome the deficiencies of the prior art, propose a three-station hybrid target positioning method combining intra-station / inter-station measurements, and provide a solution to the three-station target positioning problem.

[0009] The technical solution provided by the present invention is as follows:

[0010] In a first aspect, a three-station hybrid target positioning method based on combined intra-station / inter-station measurements includes:

[0011] Obtain DOA measurements within each radar station, divide the radar into one reference station and two receiving stations, and obtain inter-station TDOA measurements and FDOA measurements between the receiving station and the reference station;

[0012] Use DOA measurement and TDOA measurement to estimate the target X-axis coordinate and the distance from the target to the reference station;

[0013] Use FDOA measurement to correct the target X-axis coordinate and the distance from the target to the reference station;

[0014] The target Y-axis and Z-axis coordinates are determined by TDOA measurement and correction of the X-axis coordinates and the distance from the target to the reference station to complete the three-station target positioning.

[0015] In combination with the first aspect, the obtaining of DOA measurements in each radar station includes:

[0016] Assume that the air-space distributed radar network consists of a single high-orbit satellite-borne radar and K unmanned aerial vehicle-borne radars. The high-orbit satellite-borne radar transmits signals, and the unmanned aerial vehicle-borne radar only receives signals. The number of receiving radars is K = 3. The satellite navigation position is located at Considering the limited positioning accuracy of GNSS, the satellite's real position a and navigation position a o The relationship between them is described as a=a o +Δa=[x a ,y a ,z a ] T , where Δa is the satellite navigation position error and the satellite velocity is v a ; The navigation position of the i-th drone is located at Real location i and navigation location The relationship is Where Δs i is the position error of the i-th UAV, and the speed of the UAV is v s ;

[0017] Assume that the aerial target in the scene is located at u=[x,y,z] T , the actual receiving cone angle of the target observed by the i-th UAV is:

[0018]

[0019] Where e 1 =[1,0,0] T ; DOA measurement is expressed as:

[0020]

[0021] in Represents the DOA measurement noise.

[0022] In combination with the first aspect, the radar is divided into a reference station and two receiving stations, and TDOA measurement and FDOA measurement between the receiving station and the reference station are obtained, including:

[0023] The actual dual-base distance received by the i-th UAV after being launched from a high-orbit satellite and passing the target is expressed as:

[0024] b i =||ua|| 2 +||us i || 2

[0025] After distance difference,

[0026] r i1 =b i -b 1 =r i -r 1

[0027] Where r i =||us i|| 2 represents the distance from the target to the i-th UAV, then the TDOA measurement is written as:

[0028]

[0029] Where c is the speed of light, Δt i1 represents the differential delay measurement noise;

[0030] The real bistatic Doppler is:

[0031]

[0032] Where v t is the instantaneous speed of the target, λ is the wavelength,

[0033]

[0034] ψ T and are the transmitting and receiving velocity cone angles respectively. After Doppler difference,

[0035]

[0036] FDOA is measured as:

[0037]

[0038] in Represents the FDOA measurement noise.

[0039] In combination with the first aspect, the step of estimating the target X-axis coordinate and the distance from the target to the reference station by using DOA measurement and TDOA measurement includes: considering that the influence of the radar position error on the observation angle is very small, that is:

[0040]

[0041] and r i =r i1 +r 1 ,have to:

[0042]

[0043] Define parameter vector All the received radar measurements are organized into a matrix form and written as:

[0044] h a =G a v 1

[0045] Where:

[0046]

[0047] and

[0048]

[0049] Using noisy measurement vector and Respectively replace the noise-free measurement vector and r 1 =[r 21 ,r 31 ] T , then the least squares problem is established as:

[0050]

[0051] Partial target parameter v 1 The LS solution is:

[0052]

[0053] In combination with the first aspect, the step of using FDOA measurement to correct the target X-axis coordinate and the distance from the target to the reference station includes: FDOA measurement of the i-th receiving radar and the reference radar is written as:

[0054]

[0055] The velocity cone angle of the positive side-view array is equal to the array cone angle, Since the common term (v s +v t ) / λ, the constraints between FDOA measurements are:

[0056]

[0057] Will Substituting the above FDOA measurement constraint expression into the equation, we get:

[0058]

[0059] Right now:

[0060]

[0061] Will and Arranged into matrix form, we get:

[0062] h a =G a v 1

[0063] Where G a Corrected to:

[0064]

[0065] and

[0066]

[0067] In combination with the first aspect, the step of using TDOA to measure and correct the X-axis coordinates and the distance from the target to the reference station to determine the Y-axis and Z-axis coordinates of the target and complete the three-station target positioning includes:

[0068] The TDOA measurement i1 =r i -r 1 Arrange to r i1 +r 1 =r i , and square both sides to get:

[0069]

[0070] Will and Substituting in, we get:

[0071]

[0072] in and The TDOA measurements from all receiving stations are organized into a matrix form:

[0073]

[0074] In the formula v 2 =[y,z] T ,

[0075]

[0076] and

[0077]

[0078] According to the Gauss-Markov theorem, minimize in The remaining parameters v 2 The weighted least squares (WLS) estimate of is:

[0079]

[0080] In the formula is the TDOA vector, and the weight matrix W is

[0081] W=(AQ t AT +BQ s B T ) -1

[0082] Where Q t =c 2 E[ΔtΔt T ] and Q s =E[ΔsΔs T ], where Δt=[Δt 21 ,…,Δt K1 ] T and

[0083] A≈I K-1

[0084]

[0085] Finally, the three-station target positioning results are expressed as

[0086] In a second aspect, a three-station hybrid target positioning device for combined intra-station / inter-station measurement includes:

[0087] one or more processors;

[0088] a storage device for storing one or more programs,

[0089] When the one or more programs are executed by the one or more processors, the one or more processors implement the three-station hybrid target positioning method with joint intra-station / inter-station measurements as described in the first aspect.

[0090] In a third aspect, a readable storage medium stores a computer program, which, when executed by a processor, implements the three-station hybrid target positioning method with joint intra-station / inter-station measurements as described in the first aspect.

[0091] In a fourth aspect, a computer program product is provided, comprising: a computer program, which, when executed, executes the three-station hybrid target positioning method with joint intra-station / inter-station measurements as described in the first aspect.

[0092] A three-station hybrid target positioning method with combined intra-station / inter-station measurements provided by the present invention has the following beneficial effects:

[0093] (1) The present invention provides a three-station hybrid target positioning method with combined intra-station / inter-station measurements. It innovatively proposes to use DOA measurement and TDOA measurement to estimate the reference distance and target X coordinate, and uses FDOA measurement to assist in improving parameter estimation accuracy. This method reduces the number of required DOA measurements, can reduce system costs, and is easy to implement in engineering.

[0094] (2) The present invention provides a three-station hybrid target positioning method with joint intra-station / inter-station measurements, which is a target positioning method under the uncertainty of the three-station positions. This method constructs a pseudo-linear equation group to estimate the target Y and Z coordinates under the condition that the position of the receiving station is unknown by means of "compression" parameters. This method only requires three receiving stations to complete target positioning, has good robustness, and has good engineering application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0095] Figure 1 It is a flow chart of a three-station hybrid target positioning method for combined intra-station / inter-station measurement of the present invention;

[0096] Figure 2 is a scatter plot of target position estimation in an embodiment of the present invention;

[0097] Figure 3 Target positioning accuracy comparison in the embodiments of the present invention. DETAILED DESCRIPTION

[0098] The following detailed description of the present invention will make the features and advantages of the present invention more clear and explicit.

[0099] The word “exemplary” is used exclusively herein to mean “serving as an example, example, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments.

[0100] The three-station hybrid target positioning method of the present invention with combined intra-station / inter-station measurements can be applied to the field of target positioning. Figure 1 As shown in the figure, first, this method combines DOA measurement and TDOA measurement to estimate the reference distance and target X coordinate; then, FDOA measurement is used to assist in improving the accuracy of parameter estimation; finally, combined with the estimated target parameters, the parameters are "compressed" and the pseudo-linear equations are constructed using inter-station TDOA measurement to locate the target. This method only requires three receiving stations to achieve target positioning and has good engineering application prospects.

[0101] The implementation steps are as follows:

[0102] Step 1: Obtain intra-site DOA measurements and inter-site TDOA+FDOA measurements.

[0103] Assume that the air-space distributed radar network consists of a single high-orbit satellite-borne radar and K unmanned aerial vehicle radars. The high-orbit satellite-borne radar transmits signals, and the unmanned aerial vehicle radar only receives signals. In order to focus on the three-station target positioning, it is assumed that the number of receiving radars K = 3. The satellite navigation position is located at Considering the limited positioning accuracy of the global navigation satellite system (GNSS), the real satellite position a and the navigation position a o The relationship between can be described as a=a o +Δa=[x a ,y a ,z a ] T , where Δa is the satellite navigation position error and the satellite velocity is v a Similarly, the navigation position of the i-th drone is Real location i and navigation location The relationship is Where Δs i is the position error of the i-th UAV, and the speed of the UAV is v s The definitions of intra-station measurement and inter-station measurement are given below:

[0104] a) DOA measurement within the station

[0105] In-station measurement mainly refers to the target angle of arrival (DOA) measurement obtained by the antenna array angle measurement in the receiving radar. Assume that the aerial target in the scene is located at u = [x, y, z] T , the actual receiving cone angle of the target observed by the i-th UAV is:

[0106]

[0107] Where e 1 =[1,0,0] T Due to the limited angle measurement accuracy, the actual receiving cone angle Affected by measurement noise, DOA measurement can be expressed as:

[0108]

[0109] in Represents the DOA measurement noise.

[0110] b) Inter-site TDOA+FDOA measurement

[0111] One drone-mounted radar is determined as the reference station, and the other two drone-mounted radars are the receiving stations. The inter-station measurement mainly refers to the time difference of arrival (TDOA) measurement and frequency difference of arrival (FDOA) measurement obtained by the difference between the receiving station and the reference station. First, after being transmitted from a high-orbit satellite and passing the target, the real bistatic distance received by the i-th drone can be expressed as:

[0112] b i =||ua|| 2 +||usi || 2 Formula 3

[0113] After distance difference,

[0114] r i1 =b i -b 1 =r i -r 1 Formula 4

[0115] Where r i =||us i || 2 represents the distance from the target to the i-th UAV. Considering that the TDOA measurement and the range-difference of arrival (RDOA) measurement differ by only a multiplicative factor, the following text does not strictly distinguish between these two types of measurements. Then the TDOA measurement is written as:

[0116]

[0117] Where c is the speed of light, Δt i1 Represents the differential delay measurement noise.

[0118] Similarly, the true bistatic Doppler is:

[0119]

[0120] Where v t is the instantaneous speed of the target, λ is the wavelength of the transmitted signal,

[0121]

[0122] ψ T and are the transmitting velocity cone angle and the receiving velocity cone angle respectively. After Doppler difference,

[0123]

[0124] The FDOA measurement can be written as:

[0125]

[0126] in Represents the FDOA measurement noise.

[0127] Step 2: Use DOA measurement and TDOA measurement to estimate some target parameters, namely the target X-axis coordinate and the distance from the target to the reference station.

[0128] Target positioning is divided into two parts. First, considering that the radar position error has little effect on the observation angle, that is:

[0129]

[0130] and r i =r i1 +r 1 , we can get:

[0131]

[0132] is the actual receiving cone angle of the target observed by the i-th UAV, is the receiving cone angle of the target observed by the i-th UAV without considering the measurement noise;

[0133] Define parameter vector Arranging the measurements of all receiving radars into matrix form can be written as:

[0134] h a =G a v 1 Formula 12

[0135] Where:

[0136]

[0137] and:

[0138]

[0139] Using noisy measurement vector and Respectively replace the noise-free measurement vector and r 1 =[r 21 ,r 31 ] T , then the least squares (LS) problem can be established as:

[0140]

[0141] Partial target parameter v 1 The least squares solution of is:

[0142]

[0143] Step 3: Use FDOA measurement to assist in improving the estimation accuracy of the target part parameters in step 2.

[0144] The FDOA measurement of the i-th receiving radar and the reference radar is written as:

[0145]

[0146] On the other hand, the velocity cone angle of the positive side-view array is equal to the array cone angle, Since the common term (v s +v t ) / λ, the FDOA measurements can be constrained as follows:

[0147]

[0148] Substituting (10) into (18), we can obtain:

[0149]

[0150] Right now:

[0151]

[0152] Arranging equations (11) and (20) into matrix form, we can obtain:

[0153] h a =G a v 1 Formula 21

[0154] Where G a Corrected to:

[0155]

[0156] and

[0157]

[0158] Compared with step 2, step 3 introduces the FDOA measurement equation without the need for target DOA measurement at the reference station. It is worth emphasizing that the Doppler estimation accuracy needs to be high enough to use FDOA measurement to assist parameter estimation.

[0159] Step 4: Use inter-station TDOA measurements to determine the target Y-axis and Z-axis coordinates and complete three-station target positioning.

[0160] The target is located by constructing a pseudo-linear set of equations using inter-station TDOA measurements. In order to linearize the equations, the reference distance needs to be added to the parameter vector to be estimated. The aerial target positioning contains four unknown parameters, and at least five receiving stations can support the parameter identification condition. If the reference distance and target X coordinate are estimated first using intra-station measurements, the minimum number of receiving stations can be reduced to three.

[0161] The formula r i1 =r i -r 1 Arrange to r i1 +r 1 =r i , and square both sides to get:

[0162]

[0163] Will and Substituting in, we get:

[0164]

[0165] in and The TDOA measurements from all receiving stations are organized into a matrix form:

[0166]

[0167] In the formula v 2 =[y,z] T ,

[0168]

[0169] and

[0170]

[0171] According to the Gauss-Markov theorem, minimize in The remaining parameters v 2 The weighted least squares (WLS) estimate of is:

[0172]

[0173] In the formula is the TDOA vector, and the weight matrix W is:

[0174] W=(AQ t A T +BQ s B T ) -1 Formula 30

[0175] Where Q t =c 2 E[ΔtΔt T ] and Q s =E[ΔsΔs T ], where Δt=[Δt 21 ,…,Δt K1 ] T and

[0176] A≈I K-1 Formula 31

[0177]

[0178] Finally, the three-station target positioning results can be expressed as

[0179] The present invention also provides a three-station hybrid target positioning device for combined intra-station / inter-station measurement, comprising:

[0180] one or more processors;

[0181] a storage device for storing one or more programs,

[0182] When the one or more programs are executed by the one or more processors, the one or more processors implement the three-station hybrid target positioning method with joint intra-station / inter-station measurements as described in the first aspect.

[0183] The processor and storage device can be configured on any unmanned aerial vehicle equipped with a radar.

[0184] It should be understood that the processor may be a CPU, or other general-purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor, etc. It is worth noting that the processor may be a processor supporting the advanced reduced instruction set machine (ARM) architecture.

[0185] The storage device may include a read-only memory and a random access memory, and provide instructions and data to the processor. The memory may also include a non-volatile random access memory. For example, the memory may also store information about the device type.

[0186] The storage device may be a volatile memory or a nonvolatile memory, or may include both volatile and nonvolatile memory. Among them, the nonvolatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM), which is used as an external cache. By way of example but not limitation, many forms of RAM are available. For example, static RAM (SRAM), dynamic random access memory (DRAM), synchronous DRAM (SDRAM), double data rate synchronous dynamic random access memory (DDRSDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM) and direct memory bus random access memory (DRRAM).

[0187] The present invention also provides a readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the three-station hybrid target positioning method with joint intra-station / inter-station measurements as described in the first aspect.

[0188] The present invention also provides a computer program product, which includes: a computer program (also referred to as code, or instruction), which, when executed, executes the three-station hybrid target positioning method with joint intra-station / inter-station measurements described in the first aspect.

[0189] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer instructions are loaded and executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, the computer instructions can be transmitted from a website site, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (digital subscriber line, DSL) or wireless (e.g., infrared, wireless, microwave, etc.) mode to another website site, computer, server or data center.

[0190] Those of ordinary skill in the art will appreciate that the devices and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0191] The implementation effect of the present invention is further illustrated by simulation experiments below.

[0192] Assuming that the orbital altitude of the high-orbit satellite is 36000km, the variance of the three-dimensional position error is 100m, and the three-dimensional coordinates of the three drones are [200e 3 ,100e 3 ,15e 3 ] T m, [100e 3 ,200e 3 ,15.5e 3 ] T m and [200e 3 ,100e 3 ,16e 3 ] T m, the variance of the three-dimensional position error is 4m, and the flight speed is 150m / s. The aerial target is located at [250e 3 ,250e 3 ,5e 3 ] Tm, and the speed is 62.5m / s. Table 1 shows the results of using WLS-Ho, WLS-AOA / TDOA and the hybrid positioning method proposed in this invention under the condition of target SNR of 20dB:

[0193] It can be seen that since the WLS-Ho method does not meet the parameter identifiable conditions, it is impossible to locate the target and the positioning accuracy is very poor. The positioning accuracy is always within 10 5 The WLS-AOA / TDOA positioning method uses AOA / TDOA measurement to first estimate some target parameters, fill in the missing target identifiable conditions, and then estimate the remaining target parameters. The positioning accuracy is better than 1000 meters. The hybrid positioning method proposed in the present invention further considers FDOA measurement, and uses the inter-station constraint relationship between FDOA measurements to improve the target parameter estimation accuracy.

[0194] Figure 2 A scatter plot of the target position estimation of the proposed hybrid positioning method after 2000 experiments is further given. The red five-pointed star represents the actual position of the target, while the blue dot represents the estimated position of the target in each experiment. It can be seen that the estimated deviation of the target position is approximately 2000m, 2000m, and 4000m in the x, y, and z dimensions, respectively. In other words, the target position estimation is constrained in a cube centered at the target position with a length, width, and height of 2000m, 2000m, and 4000m, respectively.

[0195] Figure 3 The relationship between the standard deviation of the target positioning accuracy of the three methods and the change of SNR is further given. The black line represents the WLS-Ho method, the blue line represents the WLS-AOA / TDOA method, and the red line represents the hybrid positioning method proposed in the present invention. It can be seen that due to the unidentifiable parameters, the positioning accuracy of the WLS-Ho method hardly changes with the SNR; the positioning accuracy of the WLS-AOA / TDOA method continues to improve with the increase of SNR; due to the auxiliary FDOA measurement and estimation of some parameters, the positioning accuracy of the hybrid periodic method proposed in the present invention is better than that of the WLS-AOA / TDOA method.

[0196] Table 1 Comparison of positioning results of WLS-Ho method, WLS-AOA / TDOA method and hybrid positioning method

[0197]

[0198] Simulation analysis and conclusion: The present invention uses intra-station / inter-station measurements to locate aerial targets in an air-space network composed of high-orbit satellites and drone-borne radars. It is mainly divided into three steps: 1) Use DOA measurement and TDOA measurement to establish the LS problem about the reference distance and target X coordinate estimation; 2) Use FDOA measurement to assist in the estimation of some target parameters; 3) Use inter-station TDOA measurement to construct a pseudo-linear equation group and use the WLS method to locate the target; The proposed method only requires three radars, and under the condition of SNR of 20dB, the target positioning accuracy can be controlled within 1000 meters, which achieves good positioning of aerial targets.

[0199] The present invention has been described in detail above in conjunction with specific implementations and exemplary examples, but these descriptions cannot be understood as limiting the present invention. Those skilled in the art understand that, without departing from the spirit and scope of the present invention, a variety of equivalent substitutions, modifications or improvements may be made to the technical solution of the present invention and its implementation methods, all of which fall within the scope of the present invention. The scope of protection of the present invention shall be subject to the attached claims.

[0200] The contents not described in detail in the specification of the present invention belong to the common knowledge of those skilled in the art.

Claims

1. A three-station hybrid target positioning method with combined intra-station / inter-station measurements, characterized in that: include: Obtain DOA measurements within each radar station, divide the radar into one reference station and two receiving stations, and obtain inter-station TDOA measurements and FDOA measurements between the receiving station and the reference station; Use DOA measurement and TDOA measurement to estimate the target X-axis coordinate and the distance from the target to the reference station; Use FDOA measurement to correct the target X-axis coordinate and the distance from the target to the reference station; The target Y-axis and Z-axis coordinates are determined by TDOA measurement and correction of the X-axis coordinates and the distance from the target to the reference station to complete the three-station target positioning.

2. The three-station hybrid target positioning method of combined intra-station / inter-station measurement according to claim 1 is characterized in that: The obtaining of DOA measurements in each radar station includes: Assume that the air-space distributed radar network consists of a single high-orbit satellite-borne radar and K unmanned aerial vehicle-borne radars. The high-orbit satellite-borne radar transmits signals, and the unmanned aerial vehicle-borne radar only receives signals. The number of receiving radars is K = 3. The navigation position of the i-th unmanned aerial vehicle is located at Real location i and navigation location The relationship is Where Δs i is the position error of the i-th UAV; DOA is measured as: in represents the DOA measurement noise, represents the actual receiving cone angle of the target observed by the i-th UAV; Where u represents the position of the aerial target, u=[x,y,z] T , e1=[1,0,0] T .

3. The three-station hybrid target positioning method of combined intra-station / inter-station measurement according to claim 2 is characterized in that: The step of dividing the radar into a reference station and two receiving stations and obtaining TDOA measurement between the receiving station and the reference station includes: TDOA is measured as: Where c is the speed of light, Δt i1 represents the differential delay measurement noise, r i1 =b i -b1=r i -r1, r i =||us i ||2, represents the distance from the target to the i-th UAV; b i =||ua||2+||us i ||2, represents the real dual-base distance received by the i-th UAV after being launched from the high-orbit satellite and passing the target, where a represents the real position of the satellite, a=a o +Δa=[x a ,y a ,z a ] T , a o represents the satellite navigation position, and Δa represents the satellite navigation position error.

4. The three-station hybrid target positioning method of combined intra-station / inter-station measurement according to claim 3 is characterized in that: The step of dividing the radar into a reference station and two receiving stations and obtaining FDOA measurement between the receiving station and the reference station includes: FDOA is measured as: in represents the FDOA measurement noise, Where v a is the satellite speed, v s is the speed of the UAV carrying the radar, v t is the instantaneous speed of the target, λ is the wavelength of the transmitted signal, ψ T and are the transmitting velocity cone angle and the receiving velocity cone angle, respectively.

5. The three-station hybrid target positioning method of combined intra-station / inter-station measurement according to claim 4 is characterized in that: The step of estimating the target X-axis coordinate and the distance from the target to the reference station by using DOA measurement and TDOA measurement includes: consider and r i =r i1 +r1, we get: Define parameter vector All the received radar measurements are organized into a matrix form and written as: h a =G a v1 Where: and Using noisy measurement vector and Respectively replace the noise-free measurement vector and r1=[r 21 ,r 31 ] T , then the least squares problem is established as: The least squares solution of the partial objective parameter v1 is:

6. The three-station hybrid target positioning method of combined intra-station / inter-station measurement according to claim 5 is characterized in that: The step of correcting the target X-axis coordinate and the distance from the target to the reference station by using FDOA measurement includes: The FDOA measurement of the i-th receiving radar and the reference radar is written as: The velocity cone angle of the positive side-view array is equal to the array cone angle, Since the common term (v s +v t ) / λ, the constraints between FDOA measurements are: Will Substituting the above FDOA measurement constraint expression into the equation, we get: Right now: Will and Arranged into matrix form, we get: h a =G a v1 Where G a Corrected to: and 7. The three-station hybrid target positioning method of combined intra-station / inter-station measurement according to claim 6 is characterized in that: The steps of using TDOA to measure and correct the X-axis coordinates and the distance from the target to the reference station to determine the Y-axis and Z-axis coordinates of the target and complete the three-station target positioning include: The TDOA measurement i1 =r i -r1 sorted to r i1 +r1=r i , and square both sides to get: Will and Substituting in, we get: in and The TDOA measurements from all receiving stations are organized into a matrix form: In the formula and According to the Gauss-Markov theorem, minimize in The weighted least squares estimate of the remaining parameter v2 is: In the formula is the TDOA vector, and the weight matrix W is: W=(AQ t A T +BQ s B T ) -1 Where Q t =c 2 E[ΔtΔt T ] and Q s =E[ΔsΔs T ], where Δt=[Δt 21 ,…,Δt K1 ] T and A≈I K-1 The final three-station target positioning results are:

8. A three-station hybrid target positioning device with combined intra-station / inter-station measurements, characterized in that: include: one or more processors; a storage device for storing one or more programs, When the one or more programs are executed by the one or more processors, the one or more processors implement the three-station hybrid target positioning method with joint intra-station / inter-station measurements as described in one of claims 1 to 7.

9. A readable storage medium, characterized in that: A computer program is stored thereon, and when the program is executed by a processor, the three-station hybrid target positioning method of combined intra-station / inter-station measurement as claimed in any one of claims 1 to 7 is implemented.

10. A computer program product, characterized in that The computer program product comprises: a computer program, which, when being executed, executes the three-station hybrid target positioning method with joint intra-station / inter-station measurements as claimed in any one of claims 1 to 7.

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