Multi-platform time correction method and system based on double multi-static radar detection

Abstract

The invention discloses a multi-platform time correction method based on double multi-static radar detection, and the method comprises the following steps: initiating a time error correction task through a manual or automatic method; numbering multiple nodes of which the time is to be corrected; selecting an air-in-air common-view target; fixed-data-rate dual-multi-base detection of an aerial target is carried out; inter-node dual distance measurement: obtaining an Mth dual distance; carrying out equivalent distance fitting; and time error correction. According to the method, multi-platform real-time high-precision time synchronization error correction can be completed according to a radar detection result, the process is implemented while target detection is performed, and extra resources are not occupied; and meanwhile, a special time comparison module does not need to be additionally arranged, so that the integration level of platform equipment is improved.

Description

Technical Field

[0001] The present invention relates to the field of radar cooperative detection, and in particular to a multi-platform time correction method and system based on dual multi-base radar detection. Background Art

[0002] With the rapid development of electronic information equipment, radars face complex scenarios such as strong interference and strong clutter when performing detection tasks. It is urgent to improve the target detection and perception capabilities through effective interconnection between multiple radar detection equipment, based on the anti-interference and anti-stealth capabilities of collaborative detection. Collaborative detection is to use unified scheduling to coordinate multiple spatially distributed radars, and detect the key targets in the common view area in a collaborative mode, that is, to use the geographical location elements between multiple nodes, multi-node information joint processing, and multi-radar comprehensive scheduling to improve the distributed radar system's anti-interference, anti-anti-radiation, anti-stealth, and anti-low-altitude target capabilities.

[0003] There are many technical modes for collaborative detection, which can be divided into task-level collaboration, parameter-level collaboration, and signal-level collaboration according to their scheduling and information processing methods. Among them, the collaboration level of signal-level collaboration is the most in-depth, and the improvement of detection capabilities compared to a single platform is also the most significant. However, signal-level collaboration also has the highest requirements for time, space, and frequency synchronization between the platforms of the collaborative detection system, especially for time synchronization, whose errors directly lead to errors in distance, phase, etc., which will reduce the effectiveness of collaborative detection.

[0004] The current time synchronization methods for radar cooperative detection are mainly divided into two categories: the first category is satellite-based time synchronization methods. These mainly include satellite timing method and satellite common view method. Under normal circumstances, this type of technology can achieve high-precision time synchronization, but under extreme conditions such as unavailable satellite information (for example, satellites are interfered or in areas without satellite coverage), this method cannot be applied. The second category is the two-way time comparison method, which does not rely on satellite information. There are currently two main methods: one is the direct wave two-way time comparison method (Zou Feng, Zhang Dianyou, Research on relative ranging and two-way comparison time synchronization between ship formations [J], "Ship Electronic Countermeasures", Vol. 35, No. 6, 2012, pp. 14-17). This method is applied on the ground or ship platform. Due to the limited height of the comparison module on the platform, the effective range is limited to the line of sight; the other is the two-way time comparison based on atmospheric scattering (Chen Xihong, Liu Jiye, Liu Qiang, Liu Zan, Application of tropospheric scatter communication in high-precision time synchronization [J], "Radio Communication Technology", Vol. 44, No. 5, 2018, pp. 425-430). This method requires the comparison module of the platform sensor to have a higher radiation power to compensate for the electromagnetic wave power loss caused by atmospheric scattering, and is not suitable for small electromagnetic equipment. Summary of the invention

[0005] In order to solve the above problems, the present invention proposes a multi-platform time correction method based on dual multi-base radar detection.

[0006] Assuming there are N nodes in the radar system, the following steps are included:

[0007] The time error correction task is initiated, which can be initiated manually or automatically:

[0008] Number the multiple nodes to be corrected in time: number the main transmitting node as node 1, and the remaining nodes as nodes 2, 3, ..., N;

[0009] Aerial target selection: Aerial target A is selected as the common view target for time error correction;

[0010] Fixed data rate dual multi-base detection of aerial target A: Node 1, as the transmitting node, performs dual multi-base detection of aerial target A at a fixed data rate. The detection time is T 0i , i is 1, 2, 3, ..., I, I is a positive integer; calculate

[0011] T 0i At the moment, the distances between the aerial target A and node 1, and the distances between the aerial target A and node M are synchronously measured by other nodes M except node 1 as receiving nodes. The distance sum is defined as Distance; M∈2,3,…,N;

[0012] Dual distance measurement between nodes:

[0013] Insert N-1 time error correction time slots during the constant data rate dual multi-base detection of the aerial target A;

[0014] In the M-1th error correction time slot, node M transmits and node 1 receives. M-1 Perform dual multi-base detection on aerial target A at all times. Node 1 measures the sum of the distances between aerial target A and node 1, and between aerial target A and node M. The sum of the distances is defined as the Mth dual distance.

[0015] Equivalent distance fitting:

[0016] The first The distance is fitted with a high-order polynomial of the data, and an equivalent distance curve with time as the variable and distance as the mapping is fitted to obtain the Mth equivalent fitting distance;

[0017] Time error correction:

[0018] According to the Mth dual distance and the Mth equivalent fitting distance, the corresponding time error correction value Δt is obtained 1M ;

[0019] According to the time error correction value Δt 1M Complete error correction between all N nodes.

[0020] Furthermore, the time error correction value is Δt 1M =(Mth equivalent fitting distance-Mth dual distance) / c, where c is the speed of light.

[0021] Further, according to the time error correction value Δt 1M Get the time error Δt between the Kth and Lth nodes KL =Δt 1K –Δt 1L , thereby completing the error correction between N nodes, where K, L∈M.

[0022] Furthermore, when performing fixed data rate dual multi-base detection of aerial targets, the pulse width of node 1 as the transmitting node is τ, the gate coverage range is ±δl, and the gate start time of node M as the receiving node is delayed by T 0i for The gate end time delay T 0i for T 0i At time , the distance between aerial target A and node 1 is, T 0i At time , the distance between the aerial target A and the node M, c is the speed of light, and δl is a constant.

[0023] The value of δl is adjusted according to the situation of the aerial target. Preferably, the value of δl is 5km, 10km, and 15km.

[0024] Furthermore, in the M-1th error correction time slot, the pulse width of node M is τ, and node 1 opens the receiving wave gate according to the estimated distance from the aerial target to node 1 and node M. The wave gate coverage range is ±δl, then the receiving wave gate start delay of node 1 is t M-1 Time is Receiving gate end distance t M-1 Time is in, t M-1 At time , the distance between aerial target A and node 1 is, t M-1 At time , the distance between aerial target A and node M.

[0025] Furthermore, the time error correction task is initiated manually or automatically; manual initiation is based on the principle of expert method, and is initiated when performing signal-level collaborative tasks, multi-platform system time calibration, and time error correction accuracy testing; automatic initiation is to automatically initiate the time error correction task through collaborative task feedback and collaborative detection performance evaluation results.

[0026] Preferably, the aerial target A is selected as a target that the node 1 originally needs to perform dual multi-base detection on.

[0027] Further, the node transmits a pulse single pulse or a pulse train.

[0028] A multi-platform time correction system based on dual multi-base radar detection is also provided, and the system performs error correction between multiple nodes during radar detection according to the above method.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] (1) Without using satellite information, the line-of-sight limitation between platforms can be overcome, and the line-of-sight limitation of direct wave time comparison can be made up, and the radar does not need to have strong radiation power.

[0031] (2) It can perform distance compensation based on radar detection results and complete multi-platform real-time high-precision time synchronization error correction.

[0032] (3) It can complete time comparison while detecting the target without taking up additional resources.

[0033] (4) There is no need to add an additional dedicated comparison module, which improves the integration of platform equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a typical configuration of time error correction applicable to dual multi-base according to an embodiment of the present invention.

[0035] Figure 2 This is a timing sequence design diagram for tracking an aerial target at a constant data rate according to an embodiment of the present invention.

[0036] Figure 3 This is a timing sequence design diagram of the dual ranging timing between nodes according to an embodiment of the present invention.

[0037] Figure 4 The figure is a time error correction flow chart applicable to dual multi-base according to an embodiment of the present invention. DETAILED DESCRIPTION

[0038] In order to complete multi-platform time error correction without satellite auxiliary information, a multi-platform time correction method and system based on dual multi-base radar detection is proposed. In the normal dual multi-base target detection time, a dual distance detection time slot is inserted. The characteristics of this method are that it can perform distance compensation according to the radar detection results and complete multi-platform real-time high-precision time synchronization error correction; it can also complete time comparison while detecting targets without occupying additional resources; it does not require additional dedicated comparison modules, which improves the integration of platform equipment.

[0039] The present invention is further described in detail below in conjunction with the accompanying drawings.

[0040] Various aspects of the present invention are described in this disclosure with reference to the accompanying drawings, in which many illustrative embodiments are shown. It should be understood that the various concepts and embodiments described above, as well as those described in more detail below, can be implemented in any of a number of ways, since the concepts and embodiments disclosed in the present invention are not limited to any implementation. In addition, some aspects of the present invention can be used alone or in any suitable combination with other aspects of the present invention.

[0041] This embodiment proposes a multi-platform time correction method based on dual multi-base radar detection. Assuming that there are N nodes in the cooperative detection system, the method includes the following steps:

[0042] 1. The time error correction task is initiated, which can be initiated manually or automatically:

[0043] Manual initiation: Based on the principle of expert method, when the operator believes that time error correction needs to be initiated, it is initiated through manual selection, such as when a signal-level collaborative task, multi-platform system time calibration, time error correction accuracy test, etc. is about to be carried out;

[0044] Automatic initiation: The background automatically initiates the time error correction task based on the collaborative task feedback, collaborative detection performance evaluation and other results.

[0045] In this implementation, since the two cooperative detection nodes were about to perform a signal-level cooperative detection task, a time error correction task was initiated manually.

[0046] 2. Numbering of multiple nodes to be corrected in time: To maintain the concealment of the coordinated detection of multiple nodes, it is usually carried out in the form of split detection with one node as the main transmitter and the other nodes as receivers, so as to achieve the purpose of concealed detection of the receiving node. Without loss of generality, the transmitting node is numbered as node 1, and the other receiving nodes are numbered as nodes 2, 3, ..., N in a manually designated or automatically manner.

[0047] 3. Aerial target selection: Aerial target A is selected as the common view target for time error correction. The typical system formation is as follows: Figure 1 The common viewing target is the measurement target.

[0048] Preferably, the aerial target A can be selected as the target that the node 1 originally needs to perform dual multi-base detection on, so as to save time resources;

[0049] Preferably, A can select targets such as civil aircraft, which have the characteristics of stable flight, low acceleration, subsonic speed, and not easily affected by clutter. In this implementation, civil aircraft are selected as common-view targets, wherein the selected civil aircraft can fly at an altitude of about 10,000 meters and a speed of about 600-700 km / h.

[0050] 4. Dual multi-base detection of aerial targets at a fixed data rate: Node 1 performs dual multi-base detection of aerial targets A at a fixed data rate (in this implementation, Node 1 acts as a transmitting node to perform dual multi-base detection of civil aviation flights, starting at T0, at a data rate of 1s, and the detection time is 1min). 0i , i=1, 2, 3,…, I, I is a positive integer.

[0051] The timing design of each node is as follows Figure 2 As shown in the figure, the pulse width of the transmitting node 1 is τ, and the receiving node M (M∈2, 3, …, N) designs the receiving gate according to the distance from the target estimated position to the transmitting node 1 and the node itself. The gate coverage range is set to ±δl, and the gate start time of the receiving node is delayed by T. 0i for The gate end time delay T 0i for

[0052] Preferably, the pulse of the transmitting node can be either a single pulse or a pulse train;

[0053] Preferably, δl may be a typical value such as 5 km, 10 km, 15 km, etc.

[0054] In T 0i At time (i=1, 2, 3, ...), node M as the receiving node measures the distance between the aerial target and node 1, and the distance between the aerial target and node M, and is (The distance and Defined as distance, M∈2,3,…,N;), where, The subscript 1 represents the transmitting node number, M represents the receiving node number, The superscript is the local time T of each node 0i It is worth noting that in, T 0i At time , the distance between the target and the transmitting node 1 is, T 0i At time , the distance between the target and the receiving node M, c is the speed of light.

[0055] 5. During the time when node 1 performs dual multi-base detection on aerial target A, N-1 time error correction time slots are inserted, that is, dual ranging between nodes is performed:

[0056] In the first time error correction time slot, node 2 transmits and node 1 receives. At time t1, dual multi-base detection is performed on the aerial target A, and the dual ranging obtained is in Related timing sequence such as Figure 3 shown.

[0057] The pulse width of the transmitting node 2 is τ. The receiving node 1 opens the receiving gate according to the estimated distance from the target to nodes 1 and 2. The gate covers a range of ±δl. Then the delay t1 of the receiving gate start time of the receiving node 1 is The delay t1 of the receiving gate end time is c is the speed of light;

[0058] Preferably, the pulse of the transmitting node can be either a single pulse or a pulse train;

[0059] Preferably, δl may be a typical value such as 5 km, 10 km, 15 km, etc.

[0060] 6. Equivalent distance fitting method: The distance measured multiple times when node 1 transmits and node 2 receives Perform high-order polynomial fitting on the data to fit the equivalent distance curve Φ with time as the variable and distance as the mapping 12 (t), this curve is the fitting value of multiple measurements, which can reduce the random error caused by a single measurement. Then, at time t1, if node 1 transmits and node 2 receives, the distance between the two nodes and the aerial target A and It can also be expressed as in, is the fitting distance between the target and receiving node 1 at time t1, is the fitting distance between the target and the transmitting node 2 at time t1, where the superscript symbol ′ represents that the data is a fitting value.

[0061] 7. Time error correction: The time error Δt between node 1 and node 2 12 for The time delay of the transmitting / receiving equipment of the transmitting / receiving station involved in the traditional two-way time comparison method has been compensated in the distance measurement process, so it does not need to be considered in the time correction link.

[0062] 8. Similarly, without loss of generality, in the M-1th time error correction time slot (M∈2,…,N), node M transmits and node 1 receives, and the above steps 5-7 are repeated to obtain the Mth dual distance Indicates that at t M-1 At this moment, dual multi-base detection is performed on the aerial target A, and the target measured by node 1 is the same as the specific one of node 1; Indicates that at t M-1 At this moment, dual multi-base detection is performed on the aerial target A, and the distance between the target and the node M measured by node 1). In addition, according to the equivalent distance curve Φ between node 1 and node M 1M (t), then at t M-1 At time , if node 1 transmits and node M receives, the equivalent fitting distance is The Mth equivalent fitting distance, then the time error correction value is

[0063] 9. Error correction of each node: according to the time error value Δt between node 1 and nodes 2, 3, ..., N 12 , Δt 13 ,…,Δt 1N , then the time error Δt between the Kth and Lth nodes is KL =Δt 1K –Δt 1L , K, L∈M.

[0064] According to the above method, the error correction between all N nodes can be completed. The overall flow chart is as follows: Figure 4 shown.

[0065] The present invention is based on radar equipment on two or more platforms, and through a unique working mode, according to a certain rule, it performs alternating dual-multi-base detection of aerial targets. This method does not use satellite information, can overcome the line-of-sight limitation between platforms, and also makes up for the line-of-sight limitation of direct wave time comparison, and does not require the radar to have a strong radiation power. In addition, the characteristics of this method are that, first, it can perform distance compensation based on radar detection results and complete multi-platform real-time high-precision time synchronization error correction; second, it can complete time comparison while detecting targets without occupying additional resources; third, it does not require additional dedicated time comparison modules, which improves the integration of platform equipment. It is a multi-platform time error correction method with great engineering application prospects.

Claims

1. A multi-platform time correction method based on dual multi-base radar detection, characterized in that: Assuming there are N nodes in the radar system, the following steps are included: The time error correction task is initiated manually or automatically: Number the multiple nodes to be corrected in time: number the main transmitting node as node 1, and the remaining nodes as nodes 2, 3, ..., N; Aerial target selection: Aerial target A is selected as the common view target for time error correction; Fixed data rate dual multi-base detection of aerial target A: Node 1, as the transmitting node, performs dual multi-base detection of aerial target A at a fixed data rate. The detection time is T 0i , i is 1, 2, 3, ..., I, I is a positive integer; T 0i At time t, all nodes M except node 1 act as receiving nodes and synchronously measure the sum of the distances between aerial target A and node 1, and between aerial target A and node M. The sum of the distances is defined as Distance; M∈2,3,…,N; Dual distance measurement between nodes: N-1 time error correction time slots are inserted during the constant data rate dual multi-base detection of the aerial target A; In the M-1th error correction time slot, denoted as t M-1 , node M transmits, node 1 receives, at t M-1 Perform dual multi-base detection on aerial target A at all times. Node 1 measures the sum of the distances between aerial target A and node 1, and between aerial target A and node M. The sum of the distances is defined as the Mth dual distance. Equivalent distance fitting: The first The distance is fitted with a high-order polynomial of the data, and an equivalent distance curve with time as the variable and distance as the mapping is fitted to obtain the Mth equivalent fitting distance; Time error correction: According to the Mth dual distance and the Mth equivalent fitting distance, the corresponding time error correction value Δt is obtained 1M ; According to the time error correction value Δt 1M Complete error correction between all N nodes.

2. The multi-platform time correction method based on dual multi-base radar detection according to claim 1 is characterized in that: The time error correction value is Δt 1M =(Mth equivalent fitting distance-Mth dual distance) / c, where c is the speed of light.

3. The multi-platform time correction method based on dual multi-base radar detection according to claim 1 is characterized in that: According to the time error correction value Δt 1M Get the time error Δt between the Kth and Lth nodes KL =Δt 1K –Δt 1L , thereby completing the error correction between N nodes, where K, L∈M.

4. The multi-platform time correction method based on dual multi-base radar detection according to claim 1 is characterized in that: When performing fixed data rate dual multi-base detection of aerial targets, the pulse width of node 1 as the transmitting node is τ, the gate coverage range is ±δl, and the gate start time delay of node M as the receiving node is T 0i for The gate end time delay T 0i for T 0i At time , the distance between aerial target A and node 1 is, T 0i The distance between target A and node M in space-time at time, c is the speed of light, and δl is a constant.

5. The multi-platform time correction method based on dual multi-base radar detection according to claim 4 is characterized in that: The value of δl is adjusted according to the situation of the aerial target, and the values ​​include 5km, 10km, and 15km.

6. The multi-platform time correction method based on dual multi-base radar detection according to claim 1 is characterized in that: In the M-1th error correction time slot, the transmission pulse width of node M is τ. Node 1 opens the receiving gate based on the estimated distance from the aerial target to node 1 and node M. The gate coverage range is ±δl, so the start time of the receiving gate of node 1 is delayed by t M-1 for The delay of receiving gate end time t M-1 for in, t M-1 At time , the distance between aerial target A and node 1 is, t M-1 At time , the distance between the aerial target A and the node M, c is the speed of light.

7. The multi-platform time correction method based on dual multi-base radar detection according to claim 1 is characterized in that: The time error correction task is initiated manually or automatically. Manual initiation is based on the expert method principle and is initiated during signal-level collaborative tasks, multi-platform system time calibration, and time error correction accuracy testing. Automatic initiation is the automatic initiation of the time error correction task through collaborative task feedback and collaborative detection effectiveness evaluation results.

8. The multi-platform time correction method based on dual multi-base radar detection according to claim 1 is characterized in that: Aerial target A selects the target that node 1 originally needs to perform dual multi-base detection on, and no additional detection time is taken up.

9. The multi-platform time correction method based on dual multi-base radar detection according to claim 1 is characterized in that: The pulse of the transmitting node is a single pulse or a pulse train.

10. A multi-platform time correction system based on dual multi-base radar detection, characterized in that: The system performs error correction between multiple nodes during radar detection according to the method described in any one of claims 1 to 9.

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