A multi-platform time correction method and system based on dual multi-static radar detection

Abstract

The application discloses a kind of multi-platform time correction methods based on dual multi-static radar detection, comprising the following steps: time error correction task initiation, the task is initiated by artificial or automatic method;The multi-node to be corrected time is numbered;Air common view target selection;Air target's fixed data rate dual multi-static detection;Inter-node dual ranging: obtain the Mth dual distance;Equivalent distance fitting;Time error correction.The application can complete multi-platform real-time high-precision time synchronization error correction according to radar detection results, and the process is implemented at the same time of target detection, without occupying additional resources;At the same time, without additional dedicated time comparison module, the integration of platform equipment is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of radar cooperative detection, and in particular to a multi-platform time correction method and system based on double multi-static radar detection. BACKGROUND

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

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

[0004] Current radar cooperative detection time synchronization methods can be divided into two main categories: the first category is satellite-based time synchronization methods. This mainly includes satellite time transfer and satellite common view methods. In normal environments, this type of technology can achieve high-precision time synchronization, but in extreme conditions where satellite information is not available (such as when satellites are jammed 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. The current main methods include two kinds: one is the direct wave two-way time comparison method (Zou Feng, Zhang Dianyou, Relative Ranging and Two-Way Comparison Method Time Synchronization Research between Ship Formation [J], Shipboard Electronic Countermeasures, Vol. 35, No. 6, 2012, 14-17), which is applied to ground or ship platforms. Due to the limited height of the comparison module on the platform, the effective distance is limited to line-of-sight; the second is the two-way time comparison based on atmospheric scattering (Chen Xihong, Liu Jiyi, Liu Qiang, Liu Zan, Application of Tropospheric Scattering Communication in High-Precision Time Synchronization [J], Radio Communication Technology, Vol. 44, No. 5, 2018, 425-430), which requires a higher radiation power of the comparison module on the platform sensor to compensate for the power loss of electromagnetic waves caused by atmospheric scattering, which is not suitable for small electromagnetic devices. SUMMARY

[0005] In order to solve the above problems, the present application provides a multi-platform time correction method based on double multi-base radar detection,

[0006] Suppose that there are N nodes in the radar system, including the following steps:

[0007] Time error correction task initiation, which can be initiated by manual or automatic method:

[0008] Numbering of multi-nodes to be time corrected: the main transmitting node is numbered as node 1, and the remaining nodes are numbered as node 2, 3, …, N;

[0009] Air target selection: selecting air target A as the common view target applied to time error correction;

[0010] Fixed data rate double multi-base detection of air target A: node 1 performs double multi-base detection on air target A as a transmitting node at a fixed data rate, and the detection time is T 0i , i is 1, 2, 3, …, I, I is a positive integer; calculate

[0011] T 0i , other nodes M except node 1 as receiving nodes measure the range sum of air target A and node 1, air target A and node M at t , M is 2, 3, …, N;

[0012] Inter-node dual ranging:

[0013] Insert N-1 time error correction time slots in the process of fixed data rate double multi-base detection of air target A;

[0014] At the M-1th error correction time slot, node M transmits, node 1 receives, and performs double multi-base detection on air target A at t M-1 , node 1 measures the range sum of air target A and node 1, air target A and node M, which is defined as the Mth dual range;

[0015] Equivalent distance fitting:

[0016] Data high-order polynomial fitting is performed on the Mth range obtained by multiple measurements during the fixed data rate double multi-base detection on air target, the fitting is performed with time as the variable and distance as the mapped equivalent distance curve, and the Mth equivalent fitted distance is obtained;

[0017] Time error correction:

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

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

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

[0021] Further, according to the time error correction value Δt 1M The time error Δt KL of the Kth and Lth nodes is obtained. 1K Δt 1L , so as to complete the error correction between N nodes, wherein K, L ∈ M.

[0022] Further, when the data rate of the air target is determined, the pulse width of the node 1 as the transmitting node is τ, and the wave gate coverage range is ±δl, the wave gate starting time of the node M as the receiving node is delayed by T 0i . The wave gate ending time of the node M is delayed by T 0i . T 0i , the distance between the air target A and the node 1 is, T 0i , the distance between the air target A and the node M is, c is the speed of light, and δl is a constant.

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

[0024] Further, in the M-1th error correction time slot, the pulse width of the node M is τ, and the node 1 opens the receiving wave gate according to the estimated distance of the air target to the node 1 and the node M, and the wave gate coverage range is ±δl, so that the receiving wave gate starting delay t M-1 of the node 1 is, The receiving wave gate ending distance t M-1 of the node 1 is, Among them, t M-1 , the distance between the air target A and the node 1 is, t M-1 , the distance between the air target A and the node M is.

[0025] Further, the time error correction task is initiated by manual or automatic method; manual initiation is based on expert method principle, and is initiated under the condition of signal level coordination task, multi-platform system time calibration, and time error correction precision test; automatic initiation is automatic initiation of time error correction task through coordination task feedback and coordination detection efficiency evaluation result.

[0026] Preferably, the aerial target A is selected as a target originally requiring double multi-base detection by the node 1.

[0027] Further, the transmitting node is pulsed with single pulse or pulse train.

[0028] Further provided is a multi-platform time correction system based on double multi-base radar detection, which corrects the error between nodes during radar detection according to the above method.

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

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

[0031] (2) The present application can compensate for the distance according to the radar detection result, and complete real-time high-precision time synchronization error correction of the multi-platform.

[0032] (3) The present application can complete time comparison while detecting the target, and does not occupy additional resources.

[0033] (4) The present application does not need to additionally increase a special comparison module, and improves the integration of platform equipment. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 The present application is suitable for double multi-base time error correction.

[0035] Figure 2 The present application is suitable for double multi-base time error correction.

[0036] Figure 3 The present application is suitable for double multi-base time error correction.

[0037] Figure 4 The present application is suitable for double multi-base time error correction. DETAILED DESCRIPTION

[0038] In order to complete the time error correction of multiple platforms without satellite auxiliary information, a multiple platform time correction method and system based on dual multi-base radar detection are provided. In the normal dual multi-base target detection time, a dual distance detection time slot is inserted. The method has the characteristics that the distance compensation can be performed according to the radar detection result, the real-time high-precision time synchronization error correction of multiple platforms can be completed, the time comparison can be completed at the same time of target detection without occupying additional resources, and a dedicated comparison module does not need to be additionally added, and the platform equipment integration is improved.

[0039] The application will be described in further detail below with reference to the drawings.

[0040] Aspects of the present application are described in this disclosure with reference to the accompanying drawings, in which a number of illustrative embodiments are shown. It should be understood that various concepts and embodiments introduced above and those described in more detail below can be implemented in any of numerous ways, as the disclosed concepts and embodiments are not limited to any particular manner of implementation. Also, it should be understood that some of the aspects of the present application can be utilized independently, or in any suitable combination with any other aspect of the present application.

[0041] The embodiment provides a multiple platform time correction method based on dual multi-base radar detection. Assuming that there are N nodes in the cooperative detection system, the method comprises the following steps.

[0042] 1. Time error correction task initiation. The task can be initiated by manual or automatic method:

[0043] Manual initiation: based on the expert method principle, when the operator considers that the time error correction needs to be initiated, the time error correction is initiated by manual selection, for example, when the signal level cooperative task, the multiple platform system time calibration, the time error correction precision test and the like are to be performed.

[0044] Automatic initiation: the time error correction task is initiated by the background automatically according to the cooperative task feedback, the cooperative detection efficiency evaluation and the like.

[0045] In this implementation, the time error correction task is initiated by manual method because the two cooperative detection nodes are about to perform the signal level cooperative detection task.

[0046] 2. Numbering of the multiple nodes to be time corrected: in order to maintain the concealment of the cooperative detection multiple nodes, the transceiver separation detection is implemented in the form that one node is used as the main transmitter and the remaining nodes are used for receiving, so that the receiving nodes can achieve the purpose of concealed detection. Without loss of generality, the transmitting node is numbered as node 1, and the remaining receiving nodes are numbered as node 2, 3, …, N by manual designation or automatically.

[0047] 3. Selection of aerial targets: Aerial target A is selected as the common target for time error correction. A typical system formation is as follows: Figure 1 As shown. The common target is the measurement target.

[0048] Preferably, aerial target A can be a target that node 1 originally needed to detect using a dual-multi-base system, in order to save time and resources;

[0049] Preferably, target A can be a civil aircraft, which has the characteristics of stable flight, low acceleration, subsonic speed, and is not easily affected by clutter. In this implementation, a civil aircraft was selected as the common-line-of-sight target, with the selected civil aircraft flying at an altitude of approximately 10,000 meters and a speed of approximately 600-700 km / h.

[0050] 4. Fixed-rate dual-multistatic detection of airborne targets: Node 1, at a fixed data rate (in this implementation, Node 1 acts as the launching node to conduct dual-multistatic detection of civil aviation flights, starting at T0 with a data rate of 1 second and a detection time of 1 minute), also acts as the launching node to conduct dual-multistatic detection of airborne target A. The detection time is T. 0i , i = 1, 2, 3, ..., I, where I is a positive integer.

[0051] The timing design of each node is as follows: Figure 2 As shown. The pulse width of transmitting node 1 is τ. Receiving node M (M∈2, 3, ..., N) designs its receiving gate based on the distance from the estimated target position to transmitting node 1 and its own node. The gate coverage range is set to ±δl. Then, the gate start time delay T of the receiving node is... 0i for 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 can be a typical value such as 5km, 10km, or 15km.

[0054] In T 0i At time (i = 1, 2, 3, ...), node M, acting as the receiving node, measures the sum of the distances between the air target and node 1, and between the air target and node M. (This distance and Defined as the first Distance, M∈2,3,…,N;), where, The subscript 1 indicates the transmitting node number, and M indicates the receiving node number. The superscript represents the local time T of each node. 0i It is worth noting that... in, For T 0i At what moment, the distance between the target and launch node 1, For T 0i At time t, the distance between the target and the receiving node M is given, where c is the speed of light.

[0055] 5. During the bistatic multistatic detection of airborne target A at node 1, insert N-1 time error correction time slots, i.e., perform dual ranging between nodes:

[0056] In the first time error correction slot, node 2 transmits and node 1 receives. At time t1, bistatic multistatic detection is performed on airborne target A, and the obtained dual ranging is... in The relevant timing sequence is as follows Figure 3 As shown.

[0057] The pulse width of transmitting node 2 is τ. Receiving node 1 opens its receiving gate based on the estimated distances from the target to both nodes 1 and 2. The gate coverage range is ±δl. Therefore, the delay t1 of the receiving gate start time of receiving node 1 is... The delay t1 at the end of the receiving gate 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 can be a typical value such as 5km, 10km, or 15km.

[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 an equivalent distance curve Φ with time as the variable and distance as the mapping. 12 (t), this curve, being a fitted value from multiple measurements, can reduce the random error introduced by a single measurement. Then, at time t1, if node 1 transmits and node 2 receives, the sum of the distances between the two nodes and the airborne target A... It can also be expressed as in, Let t1 be the fitted distance between the target and receiver node 1. Let t1 be the fitted distance between the target and launch node 2, where the superscript symbol ′ indicates that the data is a fitted value.

[0061] 7. Time error correction: The time error Δt between node 1 and node 2 is then calculated. 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, and thus need not be considered in the time correction link.

[0062] 8. Similarly, without loss of generality, at the M-1th time error correction time slot (M∈2, …, N), node M transmits and node 1 receives, and the method of steps 5-7 is repeated to obtain the Mth pair of equivalent distances denotes the two multi-base station detection of the air target A at t M-1 denotes the distance between the target and node 1 measured by node 1. denotes the two multi-base station detection of the air target A at t M-1 denotes the distance between the target and node M measured by node 1. 1M (t), then at t M-1 denotes the equivalent fitting distance of node 1 transmitting and node M receiving at t denotes the Mth equivalent fitting distance, and the time error correction value is

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

[0064] According to the above method, error correction between all N nodes can be completed, and the overall flowchart is shown in Figure 4 .

[0065] The present application is based on radar equipment on two or more platforms, and through a specific working mode, the air target is alternately detected by two multi-base stations according to a certain rule. This method does not use satellite information, can overcome the line-of-sight restriction between platforms, and also makes up for the line-of-sight restriction of direct wave time comparison, and does not require the radar to have strong radiation power. In addition, the characteristics of this method are that, first, it can compensate the distance according to the radar detection result, complete the multi-platform real-time high-precision time synchronization error correction, second, it can complete the time comparison while detecting the target, without occupying additional resources, and third, it does not need to additionally increase a dedicated time comparison module, improves the integration of platform equipment, and is a multi-platform time error correction method with excellent engineering application prospect.

Claims

1. A multi-platform time correction method based on dual multi-static radar detection, characterized in that, Suppose there are N nodes in the radar system, including the following steps: Time error correction task initiation, which is initiated by manual or automatic method: Numbering of multi-nodes to be time-corrected: the main transmitting node is numbered as node 1, and the remaining nodes are numbered as node 2, 3, …, N; Air target selection: selecting air target A as the common view target applied to time error correction; Constant data rate bistatic detection of airborne target A: Node 1, acting as the transmitting node, performs bistatic detection of airborne target A at a fixed data rate for a duration of T. 0i where i is 1, 2, 3, ..., I, and I is a positive integer; T 0i At time 1, all nodes M except node 1 act as receiving nodes, synchronously measuring the sum of distances between air target A and node 1, and between air target A and node M. This sum of distances is defined as the sum of the distances between the two nodes. Distance; M∈2,3,…,N; Inter-node dual ranging: Inserting N-1 time error correction time slots in the process of data rate dual multi-base station detection of air target A; At the M-1th error correction time slot, denoted as t M-1 , node M transmits and node 1 receives, and at the time t M-1 , a double multi-base station detection is performed on the air target A, and node 1 measures the distance sum of the air target A and node 1 and the air target A and node M, which is defined as the Mth pair of distances; Equivalent distance fitting: The data obtained from multiple measurements during constant-rate bistatic multi-base detection of aerial target A is the first... The distance is fitted with a high-order polynomial to the data, and the equivalent distance curve with time as the variable and distance as the mapping is fitted, to obtain the Mth equivalent fitted distance; Time error correction: According to the Mth dual distance and the Mth equivalent fitting distance, a corresponding time error correction value At is obtained 1M ; According to the time error correction value Δt 1M The error correction between all N nodes is completed.

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

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

4. The method of claim 1, wherein, In the process of the data rate of the air target is fixed, the pulse width of the node 1 as the transmitting node is τ, the wave gate coverage is ±δl, the wave gate starting time of the node M as the receiving node is delayed T 0i For The wave gate ending time of the node M is delayed T 0i For For T 0i When the time is T, the distance between the air target A and the node 1 is, For T 0i When the time is T, the distance between the air target A and the node M is c, and δl is a constant.

5. The multi-platform time correction method based on dual multi-static radar detection according to claim 4, characterized in that, The value of δl is adjusted according to the situation of the air target, and the value includes 5km, 10km, 15km.

6. The method of claim 1, wherein, At the M-1th error correction time slot, the transmitting pulse width of node M is τ, and according to the estimated distance of the aerial target to node 1 and node M, node 1 opens a receiving gate, and the gate covers a range of ±δl, so the starting time of the receiving gate of node 1 is delayed by t M-1 For The ending time of the receiving gate is delayed by t M-1 For Wherein, t M-1 is the distance between the aerial target A and node 1 at the time t, t M-1 is the distance between the aerial target A and node M at the time t, and c is the speed of light.

7. The method of claim 1, wherein, The time error correction task is initiated by manual or automatic method; manual initiation is based on the principle of expert method, and is initiated under the condition of signal level coordination task, multi-platform system time calibration, and time error correction precision test; automatic initiation is to automatically initiate the time error correction task through the feedback of coordination task and the evaluation results of coordination detection efficiency. 8.The method of claim 1, wherein, The air target A is the target originally required to be detected by node 1, and does not occupy additional detection time.

9. The method of claim 1, wherein, The pulse of the transmitting node is single pulse or pulse train.

10. A multi-platform time correction system based on dual multi-static radar detection, characterized in that, The system corrects the error between the nodes according to the method of any one of claims 1-9 when performing radar detection.

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