Method for radar track initiation of a geosynchronous satellite based on sky-wave gate correction

Abstract

The application discloses a kind of synchronous satellite radar track initiation methods based on sky-wave gate correction, belong to the technical field of target tracking in radar data processing.This application is aimed at the problem of a large number of false tracks in track initiation in the target tracking of synchronous satellite radar.It includes establishing north-east sky right-angle coordinate system with sky-wave over-the-horizon radar receiving station as origin, determining the coordinates of synchronous satellite radar transmitting station, synchronous satellite radar receiving station and all measurement points in track initiation period;Determining the track tracking information of sky-wave over-the-horizon radar;According to the track information and state error of sky-wave over-the-horizon radar, establish the tracking gate of sky-wave over-the-horizon radar;Then, based on the traditional logical initiation method, establish the annular initiation gate of synchronous satellite radar;Finally, take the intersection of the annular gate of synchronous satellite radar and the tracking gate of sky-wave over-the-horizon radar as the correction gate of synchronous satellite radar, and perform track initiation, i.e.The starting track of synchronous satellite radar can be obtained.The application is suitable for track initiation in target tracking.

Description

TECHNICAL FIELD

[0001] The present application relates to a method for radar track initiation of a synchronous satellite based on sky-wave gate correction, and belongs to the technical field of target tracking in radar data processing. BACKGROUND

[0002] As the first step of multi-target tracking, accurate track initiation can provide a reliable basis for subsequent target state estimation, multi-target continuous tracking and situation awareness, and its importance is related to the performance and success of the entire tracking system. The commonly used track initiation methods are logical method, intuitive method and other algorithms, which are suitable for conditions with less clutter. However, in a strong clutter environment, the logical method has the disadvantage of more false tracks.

[0003] Sky-wave over-the-horizon radar and synchronous satellite radar are two means that can effectively detect remote areas. The synchronous satellite radar is located in the geosynchronous orbit, can continuously monitor a large area with a wide field of view, can quickly capture target dynamics and timely warning, and can gain valuable reaction time for the defense system. The synchronous satellite radar has high target detection accuracy, but because it is located in the geosynchronous orbit, its radar echo is very weak, resulting in a large number of false point tracks in the detected point tracks. The sky-wave over-the-horizon radar has a very long detection distance and can achieve over-the-horizon detection, and can monitor a wide area that is difficult to reach by conventional radar. It can effectively monitor large-area targets and plays an important role in marine monitoring, air target warning and other aspects. It has relatively strong anti-interference capability and still has certain work efficiency in complex electromagnetic environment, and can provide important information support for military defense and marine management. However, due to the influence of system and transmission channel, although the sky-wave over-the-horizon radar can stably track the target, its tracking accuracy is very low. Using sky-wave over-the-horizon radar detection information to guide the synchronous satellite radar to effectively initiate track and form a high-precision target track can provide an effective means for remote area detection.

[0004] At present, there is little research on the target tracking algorithm of the synchronous satellite radar. The existing track initiation algorithm will generate a large number of false tracks when processing the detection information of the synchronous satellite radar, and cannot correctly initiate the target track. SUMMARY

[0005] In view of the problem of a large number of false tracks in the target tracking of the synchronous satellite radar, the present application provides a method for radar track initiation of a synchronous satellite based on sky-wave gate correction.

[0006] The method for radar track initiation of a synchronous satellite based on sky-wave gate correction provided by the present application comprises the following steps.

[0007] Step one: establish a space coordinate system XYZ with the over-the-horizon radar receiving station as the origin, determine the coordinates of the over-the-horizon radar transmitting station and the over-the-horizon radar receiving station in the space coordinate system XYZ, and obtain the coordinates of all the detected point tracks of the over-the-horizon radar in the starting period of the flight path;

[0008] Step two: calculate the measurement of each detected point track in the measurement space of the over-the-horizon radar based on the coordinates of all the detected point tracks, including the propagation distance, the azimuth angle and the elevation angle;

[0009] Step three: convert the measurement Z k at the k moment into the space coordinate system XYZ to obtain a measurement point track set Y k ; filter the measurement point track set Y k according to the information of the over-the-horizon radar at the k moment to obtain a plurality of flight path heads;

[0010] Step four: establish a ring-shaped starting gate for each flight path head, and establish an over-the-horizon gate at the k+1 moment according to the information of the over-the-horizon radar, and take the intersection of the ring-shaped starting gate and the over-the-horizon gate at the k+1 moment as a search gate at the k+1 moment;

[0011] Step five: convert the measurement Z k+1 at the k+1 moment into the space coordinate system XYZ to obtain a measurement point track set Y k+1 ; determine the possible measurement point track corresponding to each flight path head in the measurement point track set Y k+1 based on the search gate at the k+1 moment, and establish a plurality of target possible flight paths at the k+1 moment;

[0012] Step six: extrapolate the target possible flight paths at the k+1 moment to obtain an extrapolated point and an extrapolated error covariance, establish an extrapolated gate at the k+2 moment, and then establish a search gate at the k+2 moment in combination with the over-the-horizon gate at the k+2 moment;

[0013] Step seven: convert the measurement Z k+2 at the k+2 moment into the space coordinate system XYZ to obtain a measurement point track set Y k+2 ;

[0014] Step eight: filter the measurement point track in the measurement point track set Y k+2 that falls within the search gate at the k+2 moment based on the search gate at the k+2 moment to determine an associated point; if there is an associated point in the measurement point track set Y k+2 , add the associated point to the corresponding target possible flight path at the k+1 moment; otherwise, add the current extrapolated point as the associated point to the corresponding target possible flight path at the k+1 moment; and obtain a target possible flight path at the k+2 moment;

[0015] Step 7: Repeat Step 6 until the possible target track is obtained at time k+4; if there is a related point in the set of measurement points at least at time k+2 to time k+4, the corresponding possible target track is considered to be the target track and the track start is successful; otherwise, the corresponding possible target track is cancelled.

[0016] According to the geostationary satellite radar track initiation method based on skywave gate correction of the present invention, in step two, the method for measuring the computational quantity is as follows:

[0017] Let x, y, and z represent the position information of the X, Y, and Z axes in the spatial coordinate system XYZ. Representing the velocity information along the X, Y, and Z axes, the state of the geostationary satellite radar transmitter S is expressed as follows: The state of the synchronous satellite radar receiving station R is represented as follows: The state of the probe point T is represented as Let r1 represent the distance from the geostationary satellite radar transmitting station S to the detection point, r2 represent the distance from the detection point to the satellite radar receiving station R, and r3 represent the distance from the geostationary satellite radar transmitting station S to the geostationary satellite radar receiving station R; R g Indicates the propagation distance of radar electromagnetic waves. Let θ represent the azimuth angle, which is the angle between the projection of the line connecting the detection point T and the geostationary satellite radar receiving station R onto the XOY plane and the Y-axis; let θ represent the elevation angle, which is the angle between the projection of the line connecting the detection point T and the geostationary satellite radar receiving station R onto the XOY plane and the line connecting the detection point T and the geostationary satellite radar receiving station R; then the calculation formula for the measurement is:

[0018]

[0019] According to the method for initiating a synchronous satellite radar track based on skywave gate correction of the present invention, in step three, the measurement point track set Y k Represented as:

[0020] Y k ={y k (i)|i=1,2,...,m k},

[0021] In the formula y k (i) represents the set of measurement points Y k The i-th measurement point trace, m k Y represents the set of measurement points k The number of measurement points;

[0022] Z k {z k (i)|i=1,2,...,m k};

[0023] Then zk (i) The y-value obtained by transforming to the aforementioned spatial coordinate system XYZ k (i) is:

[0024]

[0025] In the formula, η is the angle between r2 and r3. Let R be the directed line segment from the synchronous satellite radar receiving station R to the detection point T. Let R be the directed line segment from the synchronous satellite radar receiving station R to the synchronous satellite radar transmitting station S.

[0026] According to the geostationary satellite radar track initiation method based on skywave gate correction of the present invention, in step three, the measurement point track set Y is selected based on the information of the skywave over-the-horizon radar at time k. k The method for obtaining multiple trackheads is as follows:

[0027] Calculate the target state estimate of the skywave over-the-horizon radar at time k. With y k (i) The absolute distance on the X-axis and Y-axis; if the absolute distance on both the X-axis and Y-axis is not greater than the set threshold value D, then y k (i) As the trackhead, add it to the trackhead set Head;

[0028]

[0029] In the formula Let X be the position of the target on the X-axis. Let the velocity of the target be in the X-axis direction. The position of the target on the Y-axis. The velocity of the target in the Y-axis direction;

[0030]

[0031] In the formula x i,k For the i-th measurement point trace y k (i) x-axis coordinate, y i,k For the i-th measurement point trace y k (i) is the Y-axis coordinate.

[0032] According to the geostationary satellite radar track initiation method based on skywave gate correction of the present invention, in step four, the measurement point track set corresponding to the track head set Head is represented as Y. k (Head), constrained by the 3σ principle, Y k The ring-shaped initiation gate of (Head) is represented as |Y k (Head)-Y k+1 |:

[0033] max(vmin T k -3σ R ,0)≤|Y k (Head)-Y k+1 |≤v max T k +3σ R ,

[0034] In the formula v min For the target minimum flight speed, T k σ represents the time interval between adjacent moments. R v is the standard deviation. max The target is the maximum flight speed.

[0035] According to the method for initiating a synchronous satellite radar track based on skywave gate correction of the present invention, in step four, the skywave gate at time k+1 is an elliptical gate obtained by the traditional tracking method.

[0036] According to the geostationary satellite radar track initiation method based on skywave gate correction of the present invention, the elliptical gate is represented as:

[0037]

[0038] In the formula Let γ be the extrapolation error covariance, and γ be the gate number.

[0039] According to the method for initiating the track of a synchronous satellite radar based on skywave gate correction of the present invention, based on Y k+1 ={y k+1 (i)|i=1,2,...,m k+1}, y k+1 (i)=(x i,k+1 ,y i,k+1 ,z i,k+1 ), z i,k+1 Let y be the Z-axis coordinate of the i-th measurement point at time k+1; k+1 (i) The first two dimensions of variables are obtained The corresponding set is Pick The first and third dimensions are composed of The elliptical gate is then transformed into:

[0040]

[0041] According to the geostationary satellite radar track initiation method based on skywave gate correction of the present invention, the expression for searching the gate at time k+1 is:

[0042]

[0043] According to the geostationary satellite radar track initiation method based on skywave gate correction of the present invention, in step six, the method for determining the associated points is to select the measurement point track set Y. k+2 Among the measurement points that fall into the search gate at time k+2, the measurement point closest to the extrapolation point is determined as the associated point.

[0044] The beneficial effects of the present invention are as follows: The method of the present invention fuses the data of skywave over-the-horizon radar and geostationary satellite radar, realizing the geostationary satellite radar track initiation based on the guidance information of skywave over-the-horizon radar. This enables the geostationary satellite radar to effectively initiate tracks amidst a large number of false measurements, greatly reducing the false track initiation rate of geostationary satellite radar.

[0045] This invention establishes a coordinate system with the skywave over-the-horizon radar receiving station as the origin. Within this coordinate system, the tracking trajectory of the skywave over-the-horizon radar and the geometric measurement model of the geostationary satellite radar are represented. Then, through measurement space transformation, the measurements in the range-azimuth-elevation space are converted to a rectangular coordinate system. Based on the state estimation of the target and the state estimation covariance of the skywave trajectory, a skywave-corrected gate is established. A geostationary satellite radar trajectory initiation algorithm based on the skywave-corrected gate is proposed. This algorithm effectively initiates the trajectory even with numerous clutter points. Compared to the logical method, it reduces a large number of false tracks, and due to the improved search efficiency of the search gate, it effectively reduces the computational burden. Attached Figure Description

[0046] Figure 1 This is a flowchart of the initial trajectory in one initial cycle of the synchronous satellite radar trajectory initiation method based on skywave gate correction described in this invention;

[0047] Figure 2 This is a model diagram of a geostationary satellite radar measurement system in a spatial coordinate system XYZ, with the skywave over-the-horizon radar receiving station as the origin; h in the diagram T h is the height of the target. R The altitude of the synchronous satellite radar receiving station;

[0048] Figure 3 This is a simulation result diagram of the trajectory initiation based on the logic method in the absence of skywave guidance information.

[0049] Figure 4 This is a diagram showing the result of using the method of this invention to initiate a flight path under skywave guidance information;

[0050] Figure 5 The graph shows the improvement in track initiation efficiency under skywave guidance information when the distance error of the synchronous satellite radar is 3km, using the method of this invention under different skywave filtering errors, i.e., the improvement in gate search efficiency.

[0051] Figure 6 This is a graph showing the improvement in track initiation efficiency under skywave guidance information when the distance error of the synchronous satellite radar is 2km, using the method of this invention under different skywave filtering errors, i.e., the improvement in gate search efficiency. Detailed Implementation

[0052] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0053] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0054] The present invention will be further described below with reference to the accompanying drawings, but this should not be construed as limiting the invention.

[0055] Specific Implementation Method 1: Combination Figure 1 and Figure 2 As shown, this invention provides a method for initiating a geostationary satellite radar track based on skywave gate correction, comprising:

[0056] Step 1: Establish a spatial coordinate system XYZ with the skywave over-the-horizon radar receiving station as the origin, determine the coordinates of the geostationary satellite radar transmitting station and the geostationary satellite radar receiving station in the spatial coordinate system XYZ, and obtain the coordinates of all detection points of the geostationary satellite radar within the initial period of the track.

[0057] Step 2: Calculate the measurements of each detection point in the geostationary satellite radar measurement space based on the coordinates of all detection points, including propagation distance, azimuth angle, and elevation angle; calculate the propagation distance R of the signal from the geostationary satellite radar transmitting station to the geostationary satellite radar receiving station based on the coordinates of the geostationary satellite radar transmitting station, the geostationary satellite radar receiving station, and the coordinates of all detection points of the geostationary satellite radar during the initial period of the track. g The elevation angle θ and the elevation angle azimuth angle of the measurement point The measurement of each point in the geostationary satellite radar measurement space is determined as follows:

[0058] Step 3: Measure Z at time k. k Transform to the aforementioned spatial coordinate system XYZ to obtain the measurement point set Y. k The measurement point set Y is selected based on the information from the skywave over-the-horizon radar at time k. k Multiple trackheads were obtained;

[0059] Step 4: Establish a circular starting gate for each trackhead, and at the same time establish a skywave gate at time k+1 based on the information from the skywave over-the-horizon radar. The intersection of the circular starting gate and the skywave gate at time k+1 is used as the search gate at time k+1.

[0060] Step 5: Measure Z at time k+1 k+1 Transform to the aforementioned spatial coordinate system XYZ to obtain the measurement point set Y. k+1 Based on the search gate at time k+1, the set of measurement point traces Y is determined. k+1 For each possible measurement point corresponding to each track head, establish multiple possible target tracks at time k+1.

[0061] Step 6: Extrapolate the possible trajectory of the target at time k+1 to obtain the extrapolation point and the extrapolation error covariance. Establish the extrapolation gate at time k+2, and then combine it with the skywave gate at time k+2 to establish the search gate at time k+2. The size of the subsequent gates is jointly determined by the extrapolation error covariance and the skywave gate.

[0062] Measure Z at time k+2. k+2 Transform to the aforementioned spatial coordinate system XYZ to obtain the measurement point set Y. k+2 ;

[0063] Based on the search gate at time k+2, the set of measurement point traces Y is filtered. k+2 If the measurement point trace falls within the search gate at time k+2, the associated point is determined; if the measurement point trace set Y k+2 If a correlation point exists, add the correlation point to the possible trajectory of the target at time k+1; otherwise, add the current extrapolated point as a correlation point to the possible trajectory of the target at time k+1; thus obtaining the possible trajectory of the target at time k+2.

[0064] Step 7: Repeat Step 6 to extrapolate and correlate all possible tracks until the target possible track is obtained at time k+4; check the correlation records of all possible tracks from time k+2 to time k+4. If there is a correlated point in the measurement point track set at least one time from time k+2 to time k+4, then the corresponding target possible track is considered to be the target track, and the track start is successful; otherwise, the corresponding target possible track is canceled.

[0065] This implementation method establishes a north-east-sky rectangular coordinate system with the skywave over-the-horizon radar receiving station as the origin, and determines the coordinates of the skywave over-the-horizon radar track, the geostationary satellite radar transmitting station, the geostationary satellite radar receiving station, and all measurement points within the track initiation period. It then determines the skywave over-the-horizon radar track tracking information; subsequently, it establishes a skywave over-the-horizon radar tracking gate based on the skywave over-the-horizon radar track information and state error; next, it establishes a geostationary satellite radar ring initiation gate based on the traditional logical initiation method; finally, it takes the intersection of the geostationary satellite radar ring gate and the skywave over-the-horizon radar tracking gate as the geostationary satellite radar correction gate to initiate the track, thus obtaining the geostationary satellite radar's initial track.

[0066] Furthermore, combined with Figure 2 As shown, in step two, the method for calculating the quantity measurement is as follows:

[0067] Let O be the location of the skywave over-the-horizon radar receiving station and the origin of the spatial coordinate system XYZ. Let x, y, and z represent the position information of the X, Y, and Z axes in the spatial coordinate system XYZ. Representing the velocity information along the X, Y, and Z axes, the state of the geostationary satellite radar transmitter S is expressed as follows: The state of the synchronous satellite radar receiving station R is represented as follows: The state of the probe point T is represented as Let r1 represent the distance from the geostationary satellite radar transmitting station S to the detection point, r2 represent the distance from the detection point to the satellite radar receiving station R, and r3 represent the distance from the geostationary satellite radar transmitting station S to the geostationary satellite radar receiving station R; R g Indicates the propagation distance of radar electromagnetic waves. Let θ represent the azimuth angle, which is the angle between the projection of the line connecting the detection point T and the geostationary satellite radar receiving station R onto the XOY plane and the Y-axis; let θ represent the elevation angle, which is the angle between the projection of the line connecting the detection point T and the geostationary satellite radar receiving station R onto the XOY plane and the line connecting the detection point T and the geostationary satellite radar receiving station R; then the calculation formula for the measurement is:

[0068]

[0069] In step three, the measurement point set Y k Represented as:

[0070] Y k ={y k (i)|i=1,2,...,m k},

[0071] In the formula y k (i) represents the set of measurement points Y k The i-th measurement point trace, m k Y represents the set of measurement points kThe number of measurement points; y k (i)=(x i,k ,y i,k ,z i,k );

[0072] Z k {z k (i)|i=1,2,...,m k};

[0073] Then z k (i) The y-value obtained by transforming to the aforementioned spatial coordinate system XYZ k (i) is:

[0074]

[0075] In the formula, η is the angle between r2 and r3. Let R be the directed line segment from the synchronous satellite radar receiving station R to the detection point T. Let R be the directed line segment from the synchronous satellite radar receiving station R to the synchronous satellite radar transmitting station S.

[0076] In the above formula For each measurement point z k (i), x t ,y t ,z t Corresponding measurement y after conversion k (i).

[0077] In step three, the measurement point set Y is selected based on the information from the skywave over-the-horizon radar at time k. k The method for obtaining multiple trackheads is as follows:

[0078] Calculate the target state estimate of the skywave over-the-horizon radar at time k. With measurement point set Y k Each point y in k (i) The absolute distance on the X-axis and Y-axis. If the absolute distance on both the X-axis and Y-axis is not greater than the set threshold value D, then record the index of the point and set the y-axis... k (i) As the trackhead, add it to the trackhead set Head;

[0079]

[0080] In the formula Let X be the position of the target on the X-axis. Let the velocity of the target be in the X-axis direction. The position of the target on the Y-axis. The velocity of the target in the Y-axis direction;

[0081] If the measurement point Yk ={y k (i)|i=1,2,...,m k}, y k (i)=(x i,k ,y i,k ,z i,k ) Target state estimation of a skywave over-the-horizon radar at a certain point and time k When the absolute distance on the x-axis and y-axis is less than the set threshold value D, it is represented as:

[0082]

[0083] In the formula x i,k For the i-th measurement point trace y k (i) x-axis coordinate, y i,k For the i-th measurement point trace y k (i) is the Y-axis coordinate.

[0084] The measurement point that satisfies the above formula represents the i-th point at time k that meets the threshold requirement and can be used as the track head. The sequence number i is recorded in the track head set Head.

[0085] In step four, the set of measurement points corresponding to the track head set is represented as Y. k (Head), the range noise of the synchronous satellite radar has a mean of 0 and a standard deviation of σ. R A Gaussian distribution, constrained by the 3σ principle, Y k The ring-shaped initiation gate of (Head) is represented as |Y k (Head)-Y k+1 |:

[0086] max(v min T k -3σ R ,0)≤|Y k (Head)-Y k+1 |≤v max T k +3σ R ,

[0087] In the formula v min For the target minimum flight speed, T k σ represents the time interval between adjacent moments. R v is the standard deviation. max The target is the maximum flight speed.

[0088] In step four, during the guidance at time k+1, the skywave gate is an elliptical gate obtained using the traditional tracking method, which serves as a correction gate for the circular initial gate.

[0089] An elliptical gate is represented as:

[0090]

[0091] In the formula The extrapolation error covariance is given by γ, where γ is the gate number, which can be referenced from χ. 2 The distribution table is obtained.

[0092] In the formula for The conjugate transpose of .

[0093] Because Y k+1 middle y k+1 (i) is a 3×1 matrix. It's a 4×1 matrix, with each dimension having a different meaning, so alignment is necessary; because Y k+1 and Since they are all in the same coordinate system, we only need to extract and align the dimensions that have the same meaning; according to Y... k+1 ={y k+1 (i)|i=1,2,...,m k+1}, y k+1 (i)=(x i,k+1 ,y i,k+1 ,z i,k+1 ), z i,k+1 Let y be the Z-axis coordinate of the i-th measurement point at time k+1; k+1 (i) The first two dimensions of variables are obtained The corresponding set is Pick The first and third dimensions are composed of The elliptical gate is then transformed into:

[0094]

[0095] Therefore, the final expression for searching the gate at time k+1 is:

[0096]

[0097] If the trackhead set Head and the synchronous satellite radar measurement at time k+1 are Y k+1 The i-th measurement If the above formula is satisfied, it means that the trackhead and the measurement can establish a possible track.

[0098] To demonstrate the beneficial effects of the present invention, the following simulation was performed.

[0099] Simulation 1: Assume the skywave over-the-horizon radar receiving station has latitude, longitude, and altitude coordinates of (61°N, -2°E, 0km), the geostationary satellite radar transmitting station has latitude, longitude, and altitude coordinates of (0°N, 140°E, 35786km), the geostationary satellite radar receiving station is an airborne platform with latitude, longitude, and altitude coordinates of (60°N, 0°E, 100km), and the initial target position is set to (59°N, 0°E, 10km). In a Cartesian coordinate system with the skywave over-the-horizon radar receiving station as the origin, the velocity (v) of the airborne platform is... x ,v y ,v z ) = (0, 2m / s, 0), the target velocity is (v x ,v y ,v z The clutter speed is (50m / s, 100m / s, 0), the scan period is 5, and the scan period interval is 30s. Furthermore, the clutter generation follows a Poisson distribution λ = 60, and the clutter points are uniformly distributed in the Cartesian coordinate space 100km≤x≤150km, -250km≤y≤-200km, 2km≤z≤5km. The algorithmic advantages and disadvantages of this invention's method and the logic method are compared in terms of the number of false tracks. Simulation results are as follows... Figure 3 and Figure 4 As shown.

[0100] The simulation results show that when there are many clutter points, the logic method generates 313 tracks, of which only one is the correct target track, and the remaining 312 are false tracks. The method of this invention produces only one track, which is the target track.

[0101] Simulation 2: The geostationary satellite radar search gate based on skywave gate correction can effectively reduce the gate search area during track initiation and improve gate search efficiency. Performance verification is presented below. The gate search area is related to the filtering accuracy of the skywave over-the-horizon radar; therefore, it is necessary to explore the improvement in secondary guidance gate search efficiency based on different skywave filtering errors. The false alarm rate of the UAV payload is 1e-6. Assuming the UAV payload range error is 3km / 2km and the time interval is 30s, the radial range filtering errors of the skywave over-the-horizon radar after ionospheric correction are [1.5km, 1.8km, 2.1km, 2.4km, 2.7km, 3km], and the ground azimuth filtering errors are [0.001rad, 0.002rad, 0.003rad, 0.004rad, 0.005rad, 0.006rad, 0.007rad, 0.008rad, 0.009rad, 0.01rad]. Simulations are performed under the condition of fixed range filtering error and varying azimuth filtering error. The target coordinates in the two-dimensional plane are [1000e3, 200, 1000e3, 200]. The results of 1000 Monte Carlo simulations are as follows: Figure 5 and Figure 6As shown.

[0102] The 1000 Monte Carlo simulations show that, compared to the ring gate, the search efficiency of the geostationary satellite radar search gate based on the skywave gate correction is improved by more than 88%, while the computational burden is reduced by more than 88%.

[0103] In summary, the algorithm of this invention is superior to the logic method in environments with a lot of clutter.

[0104] While the invention has been described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the invention. Therefore, it should be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed without departing from the spirit and scope of the invention as defined by the appended claims. It should be understood that different dependent claims and features described herein can be combined in ways different from those described in the original claims. It is also understood that features described in conjunction with individual embodiments can be used in other described embodiments.

Claims

1. A method for initiating a geostationary satellite radar track based on skywave gate correction, characterized in that, include: Step 1: Establish a spatial coordinate system XYZ with the skywave over-the-horizon radar receiving station as the origin, determine the coordinates of the geostationary satellite radar transmitting station and the geostationary satellite radar receiving station in the spatial coordinate system XYZ, and obtain the coordinates of all detection points of the geostationary satellite radar within the initial period of the track. Step 2: Calculate the measurements of each detection point in the geostationary satellite radar measurement space based on the coordinates of all detection points, including propagation distance, azimuth angle, and elevation angle; Step 3: Measure Z at time k. k Transform to the aforementioned spatial coordinate system XYZ to obtain the measurement point set Y. k The measurement point set Y is selected based on the information from the skywave over-the-horizon radar at time k. k Multiple trackheads were obtained; Step 4: Establish a circular starting gate for each trackhead, and at the same time establish a skywave gate at time k+1 based on the information from the skywave over-the-horizon radar. The intersection of the circular starting gate and the skywave gate at time k+1 is used as the search gate at time k+1. Step 5: Measure Z at time k+1 k+1 Transform to the aforementioned spatial coordinate system XYZ to obtain the measurement point set Y. k+1 Based on the search gate at time k+1, the set of measurement point traces Y is determined. k+1 For each possible measurement point corresponding to each track head, establish multiple possible target tracks at time k+1. Step 6: Extrapolate the possible trajectory of the target at time k+1 to obtain the extrapolation point and the extrapolation error covariance, establish the extrapolation gate at time k+2, and then combine it with the skywave gate at time k+2 to establish the search gate at time k+2. Measure Z at time k+2. k+2 Transform to the aforementioned spatial coordinate system XYZ to obtain the measurement point set Y. k+2 ; Based on the search gate at time k+2, the set of measurement point traces Y is filtered. k+2 If the measurement point trace falls within the search gate at time k+2, the associated point is determined; if the measurement point trace set Y k+2 If there are related points, add the related points to the possible trajectory of the target at the corresponding k+1 time. Otherwise, add the current extrapolated point as the associated point to the possible trajectory of the target at time k+1; thus obtaining the possible trajectory of the target at time k+2. Step 7: Repeat Step 6 until the possible target track is obtained at time k+4; if there is a related point in the set of measurement points at least at time k+2 to time k+4, the corresponding possible target track is considered to be the target track and the track start is successful; otherwise, the corresponding possible target track is cancelled.

2. The method for initiating a geostationary satellite radar track based on skywave gate correction according to claim 1, characterized in that, In step two, the method for measuring the calculated quantity is as follows: Let x, y, and z represent the position information of the X, Y, and Z axes in the spatial coordinate system XYZ. Representing the velocity information along the X, Y, and Z axes, the state of the geostationary satellite radar transmitter S is expressed as follows: The state of the synchronous satellite radar receiving station R is represented as follows: The state of the probe point T is represented as Let r1 represent the distance from the geostationary satellite radar transmitting station S to the detection point, r2 represent the distance from the detection point to the satellite radar receiving station R, and r3 represent the distance from the geostationary satellite radar transmitting station S to the geostationary satellite radar receiving station R; R g Indicates the propagation distance of radar electromagnetic waves. Let θ represent the azimuth angle, which is the angle between the projection of the line connecting the detection point T and the geostationary satellite radar receiving station R onto the XOY plane and the Y-axis; let θ represent the elevation angle, which is the angle between the projection of the line connecting the detection point T and the geostationary satellite radar receiving station R onto the XOY plane and the line connecting the detection point T and the geostationary satellite radar receiving station R; then the calculation formula for the measurement is:

3. The method for initiating a geostationary satellite radar track based on skywave gate correction according to claim 2, characterized in that, In step three, the measurement point set Y k Represented as: Y k ={y k (i)|i=1,2,...,m k }, In the formula y k (i) represents the set of measurement points Y k The i-th measurement point trace, m k Y represents the set of measurement points k The number of measurement points; Z k {z k (i)|i=1,2,...,m k }; Then z k (i) The y-value obtained by transforming to the aforementioned spatial coordinate system XYZ k (i) is: In the formula, η is the angle between r2 and r3. Let R be the directed line segment from the synchronous satellite radar receiving station R to the detection point T. Let R be the directed line segment from the synchronous satellite radar receiving station R to the synchronous satellite radar transmitting station S.

4. The method for initiating a geostationary satellite radar track based on skywave gate correction according to claim 3, characterized in that, In step three, the measurement point set Y is selected based on the information from the skywave over-the-horizon radar at time k. k The method for obtaining multiple trackheads is as follows: Calculate the target state estimate of the skywave over-the-horizon radar at time k. With y k (i) The absolute distance on the X-axis and Y-axis; if the absolute distance on both the X-axis and Y-axis is not greater than the set threshold value D, then y k (i) As the trackhead, add it to the trackhead set Head; In the formula Let X be the position of the target on the X-axis. Let the velocity of the target be in the X-axis direction. The position of the target on the Y-axis. The velocity of the target in the Y-axis direction; In the formula x i,k For the i-th measurement point trace y k (i) x-axis coordinate, y i,k For the i-th measurement point trace y k (i) is the Y-axis coordinate.

5. The method for initiating a geostationary satellite radar track based on skywave gate correction according to claim 4, characterized in that, In step four, the set of measurement points corresponding to the track head set is represented as Y. k (Head), constrained by the 3σ principle, Y k The ring-shaped initiation gate of (Head) is represented as |Y k (Head)-Y k+1 |: max(v min T k -3σ R ,0)≤|Y k (Head)-Y k+1 |≤v max T k +3σ R , In the formula v min For the target minimum flight speed, T k σ represents the time interval between adjacent moments. R v is the standard deviation. max The target is the maximum flight speed.

6. The method for initiating a geostationary satellite radar track based on skywave gate correction according to claim 5, characterized in that, In step four, the skywave gate at time k+1 is an elliptical gate obtained using the traditional tracking method.

7. The method for initiating a geostationary satellite radar track based on skywave gate correction according to claim 6, characterized in that, An elliptical gate is represented as: In the formula Let γ be the extrapolation error covariance, and γ be the gate number.

8. The method for initiating a geostationary satellite radar track based on skywave gate correction according to claim 7, characterized in that, According to Y k+1 ={y k+1 (i)|i=1,2,...,m k+1 }, y k+1 (i)=(x i,k+1 ,y i,k+1 ,z i,k+1 ), z i,k+1 Let y be the Z-axis coordinate of the i-th measurement point at time k+1; k+1 (i) The first two dimensions of variables are obtained The corresponding set is Pick The first and third dimensions are composed of The elliptical gate is then transformed into:

9. The method for initiating a geostationary satellite radar track based on skywave gate correction according to claim 8, characterized in that, The expression for searching the gate at time k+1 is:

10. The method for initiating a geostationary satellite radar track based on skywave gate correction according to claim 1, characterized in that, In step six, the method for determining the associated points is to select the measurement point trace set Y. k+2 Among the measurement points that fall into the search gate at time k+2, the measurement point closest to the extrapolation point is determined as the associated point.

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