Passive phased array radar tracking frequency prediction method

Abstract

The invention belongs to the technical field of passive phased array radar radiation source tracking, and particularly relates to a passive phased array radar tracking frequency prediction method, which mainly solves the problem that when a passive phased array radar carries out passive detection tracking on an airborne AESA radar radiation source, the tracking frequency of the passive phased array radar cannot be predicted. The problem that the tracking frequency is difficult to set due to the fact that the carrier frequency agility range of the airborne AESA is large and changes are complex is solved. The method comprises the following implementation steps of: 1, caching all PDWs of a certain key target in a current resident area; 2, grouping all the cached PDWs of the key target according to frequency; 3, extracting a frequency hopping rule according to a frequency grouping result; 4, combining all extracted frequency hopping rules and updating statistical values of the hopping rules; 5, predicting the tracking frequency of the next resident to the key target according to the merged frequency hopping rule; according to the method, the tracking stability of passive detection of the airborne AESA radar radiation source can be improved, and the method can be used for a radar detection system.

Description

Technical Field

[0001] The invention belongs to the technical field of passive phased array radar radiation source tracking. Background Art

[0002] When a passive phased array radar tracks a radiation source target, it is usually necessary to determine the tracking task and its parameters for the next dwell at each dwell. The main parameters include tracking beam pointing, tracking frequency, sampling period, etc. Regarding the tracking frequency, a radiation source that does not adopt frequency agility can obtain it when the radiation source target is discovered. However, with the widespread application of frequency agility technology, especially airborne active phased array (AESA) radars have been able to achieve millisecond-level operating frequency group changes, and the agile bandwidth range is large, reaching hundreds of MHz or even GHz, resulting in its frequency hopping range may exceed the instantaneous working bandwidth of the passive phased array radar, which makes the setting of the tracking frequency more important. Incorrect tracking frequency setting may cause a significant drop in the probability of interception or even failure to intercept.

[0003] How to effectively set the tracking frequency for airborne AESA radar is a technical problem. It is urgent to design a tracking frequency calculation method for the airborne AESA radar radiator to calculate / predict the tracking frequency setting for passive detection at the next dwell time and improve the tracking stability. Summary of the invention

[0004] Aiming at the problem that it is difficult to set the tracking frequency when performing passive detection on airborne AESA radar radiation source due to the large carrier frequency agility range, the present invention provides a passive phased array radar tracking frequency prediction method, which can effectively predict the tracking frequency for passive detection at the next dwell time by frequency grouping, frequency hopping rule extraction, frequency hopping rule merging and tracking frequency prediction of intercepted airborne AESA radar radiation source pulses, thereby improving tracking stability.

[0005] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0006] Step 1, cache key target PDW: for a certain radiation source key target T, cache all PDWs of the key target currently resident;

[0007] Step 2: PDWs are grouped by frequency: All cached PDWs are traversed in order of arrival time. For any pulse p i and p i+1 , if the frequency difference between the two is less than the threshold Th f , then p i and p i+1 Put them into the same pulse group, otherwise create a new pulse group and put the pulse p i+1 Put this pulse group as the first pulse;

[0008] Step 3: Extract frequency hopping rules: traverse all pulse groups generated after PDW frequency grouping, if the arrival time difference of two adjacent pulse groups in the time domain is less than the time threshold Th toa , then extract a frequency hopping rule: f A →f B , where f A is the frequency center value of the previous pulse group, f B is the frequency center value of the next pulse group; the initial value of the statistical value of each jump rule is set to 1;

[0009] Step 4: Merge frequency hopping rules: For any two frequency hopping rules f A →f B and f P →f Q If the conditions described in formula (1) are met, the two rules are considered to be the same and f is deleted. P →f Q , and the jump rule f A →f B The corresponding statistical value is increased by one;

[0010]

[0011] where f t is the preset frequency tolerance;

[0012] Step 5: Predict the tracking frequency: Assume that the frequency value of the last pulse group intercepted in the time domain of the current resident key target T is f cur , find all frequency hopping rules and calculate the tracking frequency of the next resident key target T.

[0013] The beneficial effects of the present invention are as follows: by frequency grouping, frequency hopping rule extraction, frequency hopping rule merging and tracking frequency prediction of the intercepted PDW, the present invention can achieve effective prediction of the tracking frequency for passive detection at the next dwell time, thereby improving tracking stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 : Flowchart of a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0015] The present invention will be further described below in conjunction with the accompanying drawings:

[0016] Figure 1 The flowchart of the preferred embodiment of the present invention comprises the following steps:

[0017] Step 1, cache key target PDW: for a certain radiation source key target T, cache all PDWs of the key target currently resident;

[0018] Step 2: PDWs are grouped by frequency: All cached PDWs are traversed in order of arrival time. For any pulse p i and p i+1 , if the frequency difference between the two is less than the threshold Th f , then p i and p i+1 Put them into the same pulse group, otherwise create a new pulse group and put the pulse p i+1 Put this pulse group as the first pulse;

[0019] Step 3: Extract frequency hopping rules: traverse all pulse groups generated after PDW frequency grouping, if the arrival time difference of two adjacent pulse groups in the time domain is less than the time threshold Th toa , then extract a frequency hopping rule: f A →f B , where f A is the frequency center value of the previous pulse group, f B is the frequency center value of the next pulse group; the initial value of the statistical value of each jump rule is set to 1;

[0020] The preferred calculation process of the arrival time difference of two pulse groups includes: for two pulse groups PG i and PG j , let T j For the next pulse group PG j The first pulse arrival time, T i PG for the previous pulse group i The arrival time of the first pulse of the two pulse groups is T. j -T i ;

[0021] Step 4: Merge frequency hopping rules: For any two frequency hopping rules f A →f B and f P →f Q If the conditions described in formula (1) are met, the two rules are considered to be the same and f is deleted. P →f Q , and the jump rule f A →f B The corresponding statistical value is increased by one;

[0022]

[0023] where f t is the preset frequency tolerance;

[0024] Step 5: Predict the tracking frequency: Assume that the frequency value of the last pulse group intercepted in the time domain of the current resident key target T is fcur , find all frequency hopping rules and calculate the tracking frequency of the next resident key target T, and optimize the following process:

[0025] (5.1) Let the frequency of the last pulse group intercepted in the time domain of the current resident key target T be f cur , find all frequency hopping rules, for any frequency hopping rule f m →f n , if |f cur -f m |≤f t , then the frequency value f n Put into the set F, f n The corresponding support value is the jump rule f m →f n Statistical value of

[0026] (5.2) After traversing the frequency hopping rules, all frequency values ​​in the set F are sorted according to the support degree. The frequency value with the largest support degree is the next tracking center frequency point f of the key target T. next , the tracking frequency is Where B is the instantaneous bandwidth of the passive phased array radar.

Claims

1. A method for predicting tracking frequency of a passive phased array radar, characterized in that: The following steps are involved: Step 1, cache key target PDW: for a certain radiation source key target T, cache all PDWs of the key target currently resident; Step 2: PDWs are grouped by frequency: All cached PDWs are traversed in order of arrival time. For any pulse p i and p i+1 , if the frequency difference between the two is less than the threshold Th f , then p i and p i+1 Put them into the same pulse group, otherwise create a new pulse group and put the pulse p i+1 Put this pulse group as the first pulse; Step 3: Extract frequency hopping rules: traverse all pulse groups generated after PDW frequency grouping, if the arrival time difference of two adjacent pulse groups in the time domain is less than the time threshold Th toa , then extract a frequency hopping rule: f A →f B , where f A is the frequency center value of the previous pulse group, f B is the frequency center value of the next pulse group; the initial value of the statistical value of each jump rule is set to 1; Step 4: Merge frequency hopping rules: For any two frequency hopping rules f A →f B and f P →f Q If the conditions described in formula (1) are met, the two rules are considered to be the same and f is deleted. P →f Q , and the jump rule f A →f B The corresponding statistical value is increased by one; where f t is the preset frequency tolerance; Step 5: Predict the tracking frequency: Assume that the frequency value of the last pulse group intercepted in the time domain of the current resident key target T is f cur , find all frequency hopping rules and calculate the tracking frequency of the next resident key target T.

2. The method for predicting tracking frequency of a passive phased array radar according to claim 1, characterized in that: The method for calculating the arrival time difference of two adjacent pulse groups in the time domain in step 3 includes: for two pulse groups PG i and PG j , let T j For the next pulse group PG j The first pulse arrival time, T i PG for the previous pulse group i The arrival time of the first pulse of the two pulse groups is T. j -T i .

3. The method for predicting tracking frequency of a passive phased array radar according to claim 1, characterized in that: The step 5 also includes: (5.1) Let the frequency of the last pulse group intercepted in the time domain of the current resident key target T be f cur , find all frequency hopping rules, for any frequency hopping rule f m →f n , if |f cur -f m |≤f t , then the frequency value f n Put into the set F, f n The corresponding support value is the jump rule f m →f n Statistical value of (5.2) After traversing the frequency hopping rules, all frequency values ​​in the set F are sorted according to the support degree. The frequency value with the largest support degree is the next tracking center frequency point f of the key target T. next , the tracking frequency is Where B is the instantaneous bandwidth of the passive phased array radar.

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