An Online Elevation Error Estimation Method for a Phase-Scanning Array Radar

Abstract

The present invention provides an online elevation error estimation method for a phase-scanning array radar, belonging to the technical field of radar. The elevation estimation value of an airborne isolated flying target is obtained from the main channel of the radar, and the wave path difference data is obtained from the auxiliary channel to calculate the incident angle of this batch of targets, and then the elevation error estimation is made. The present invention has the advantages of low complexity, strong real-time performance, fast processing speed, convenient engineering implementation, etc., and can be used for the online rapid evaluation of the elevation error during the use of a phased array radar and the online measurement of the influence degree of local function weakening on the elevation error.

Description

Technical Field

[0001] The present invention belongs to the technical field of radar. Background Art

[0002] As an important part of modern weapon systems, phased array radars can provide information such as the distance, angle, and speed of targets; during their operation, due to the performance degradation of some components or analog devices, the detection performance of the radar system will decline. Sometimes, it is difficult to detect the decline in accuracy, and it is necessary to use other detection devices to synchronously record the targets for comparison or to discover problems through elevation angle accuracy tests. To compare using the detection results of other devices, this device needs to have better detection accuracy than the radar device, and it also needs to detect the same batch of targets under the same timekeeping system. Sometimes, these two conditions may not be met simultaneously; conducting elevation angle accuracy tests requires coordinating military forces and airspace, which requires costs and time periods and is not convenient for work. Therefore, by fully utilizing the equipment of the phased array radar itself, the incident angle of the target is calculated online in real time by adding auxiliary channels, and then the elevation angle error of the radar is quickly evaluated, providing conditions for quickly positioning elevation angle accuracy problems or formulating scientific maintenance decisions. Summary of the Invention

[0003] To overcome the complexity of the existing elevation angle error estimation method, the present invention proposes an online elevation angle error estimation method for a phase-scanning array radar, obtaining the elevation angle estimate of an isolated target in the air from the main channel, calculating the incident angle of this batch of targets from the auxiliary channel, and then making an elevation angle error estimate.

[0004] The technical solution of the present invention includes:[[]]

[0005] Step 1: Main channel traction. The operator observes the display and control screen, selects an isolated target flying towards the station with a relatively strong echo amplitude, sends the target track information and gate size information to the auxiliary channel, and issues a gate acquisition command to the auxiliary channel.

[0006] Step 2: Auxiliary channel target gate acquisition and wave path difference calculation.

[0007] Step 3: Auxiliary channel calculates the incident angle. According to the distribution relationship of the wave path differences between the array radar array elements, the incident angle is calculated from the wave path difference.

[0008] Step 4: Elevation angle error estimation. Based on the time stamp, the elevation angle estimate of the main channel is compared with the calculated value of the incident angle of the auxiliary channel to perform elevation angle error estimation.

[0009] The auxiliary channel realizes gate acquisition of the target echo data, selects the point with the largest echo envelope within the gate for phase calculation of each channel. The phase of the echo of each array element is subtracted from the phase of the first array element to calculate the wave path difference of each array element. Preferably, the steps for the auxiliary channel to calculate the wave path difference in step 2 include:[[]]

[0010] 1) The auxiliary channel performs gate acquisition on the I and Q data of the wavefront transmitted by the optical fiber, and parses out the data within the range gate for each pulse according to the data protocol;

[0011] 2) Perform pulse compression processing on the data within the range gate;

[0012] 3) Take the modulus of the data within the range gate;

[0013] 4) Select the point with the maximum amplitude from the data after taking the modulus of the pulse compression within the range gate;

[0014] 5) Repeat steps 1) to 4) for each pulse within the azimuth gate;

[0015] 6) Select the point with the maximum value of the echo envelope within the gate;

[0016] 7) Calculate the phases of the echoes of each array element corresponding to the point with the maximum value within the gate;

[0017] 8) Perform amplitude-phase compensation on each receiving channel;

[0018] 9) Calculate the path difference of each array element relative to the first array element.

[0019] Calculate the incident angle based on the path difference:

[0020] θ = 2 * 180 * (d * sin(δ * pi / 180) / λ)

[0021] where θ is the incident angle, d is the element spacing, λ is the wavelength, and δ is the path difference.

[0022] The elevation error evaluation software receives the track data of the main channel of the target to be measured and the incident angle information measured by the auxiliary channel, compares the angle information of the main channel and the auxiliary channel based on the time stamp, and obtains the elevation deviation of this batch of targets; repeat the above process, and perform gate acquisition and analysis on multiple batches of targets in the air in turn to ensure the elevation airspace coverage. Display the elevation deviation data intuitively in the form of a chart in the form of elevation_deviation value, and give an evaluation report.

[0023] Compared with the prior art, the remarkable advantages of the present invention are:

[0024] 1) This method has the advantages of low complexity, strong real-time performance, fast processing speed, and convenient engineering implementation. It can evaluate the elevation deviation online, overcoming the deficiencies of the existing elevation deviation calibration methods, such as large workload, difficult coordination of troops, and long cycle;

[0025] 2) It can be used for early warning of elevation deviation during the use of phased array radars and evaluate the influence degree of local function weakening on elevation deviation, providing a basis for scientifically formulating maintenance decisions. Description of the Drawings

[0026] Figure 1 This is the functional block diagram of the present invention. Specific embodiments

[0027] The present invention will be further explained and illustrated in conjunction with the accompanying drawings and embodiments.

[0028] The present invention proposes an online elevation error estimation method for a phase-scanned array radar. On the basis of the unchanged main channel of the original radar system, an auxiliary channel is added; an air target is preferentially selected, and the target position information is transmitted to the auxiliary channel for I, Q data gating acquisition and processing; after receiving the instruction, the auxiliary channel synchronously acquires, pulse compresses, calculates the modulus, selects the maximum point of the array zero IF echo data, calculates the phase of the maximum point of each array element, calculates the wave path difference, and obtains the incident angle from the wave path difference; according to the time stamp information, the main channel elevation estimation data and the auxiliary channel data are compared, thereby realizing the online estimation of the elevation error. The online elevation error estimation system architecture of the phase-scanned array radar includes a main channel, an auxiliary channel, an information and data interaction link, and an evaluation display. The target echo I, Q signals received by the array antenna are split into two by an optical power splitter and then synchronously sent to the main channel and the auxiliary channel by optical fiber. The main channel of the array radar receives the I, Q data of the array antenna, performs amplitude-phase correction, digital beamforming, pulse compression, moving target, constant false alarm processing, detection, tracking and other processing, and outputs target points and tracks. The auxiliary channel performs gating acquisition, pulse compression, modulus calculation and selection of the selected target I, Q data, calculates the wave path difference, and obtains the target arrival angle. The target information of the main channel and the arrival angle information of the auxiliary channel are sent to the elevation error estimation software through the network to give an evaluation result.

[0029] The signal flow of the radar main channel is to receive the echo signal of the array antenna, form multiple receiving beams by digital beamforming, and estimate the target elevation angle through processes such as pulse compression, moving target processing, constant false alarm, detection, clustering, and tracking; the operator observes the target echo data through the display and control screen. When the target is isolated, flying towards the station, and the target echo amplitude meets the test conditions of the auxiliary channel, a gating acquisition instruction is issued, and at the same time, the target track information and the gating size information are sent to the auxiliary channel; the size of the range gate should be greater than the signal pulse width to completely acquire the range-dimensional target pulse echo data; the azimuth gate should be greater than the radar azimuth width to completely acquire the azimuth envelope data.

[0030] According to Figure 1 As shown, the preferred embodiments of the present invention include the following steps:

[0031] Step 1: Main channel target selection and traction

[0032] The main channel receives the echo signal of the array antenna, forms multiple receiving beams by digital beamforming, and estimates the target elevation angle through processes such as pulse compression, detection, clustering, and tracking;

[0033] (1) Obtain the echo I and Q data of M array elements

[0034] Input the echo data X composed of M-channel IQ digital signals received by M array elements: 1 = I 1 + jQ 1 , X 2 = I 2 + jQ 2 , …, X M = I M + jQ M , and this echo data contains the direct wave and noise components;

[0035] (2) Form N receiving beams

[0036] Perform DBF (Digital Beamforming) operation to simultaneously form N receiving beam I and Q data with different overlapping directions in the vertical plane: beam1, beam2, beam3, ……, beamN, covering a certain elevation angle space in the geodetic coordinates;

[0037] (3) Perform pulse compression and modulus calculation on each beam;

[0038] (4) Detect, perform correlation processing, and condensation calculation to obtain the elevation angle value;

[0039] Perform detection, range-azimuth-elevation correlation, and condensation processing on the data of N beams to obtain the track value of the target;

[0040] (5) The operator selects isolated and approaching targets through the display and control interface, records and tracks them, outputs the track data, gate data, acquisition instructions, etc. of this batch of targets to the auxiliary channel, issues a gate acquisition instruction to this batch of targets, and the size of the range gate is set according to the pulse signal width and the radar range tracking accuracy, which can ensure the acquisition of the complete range dimension echo envelope of the target; the azimuth gate is set to twice the radar beam width, and the data within the azimuth beam width can be completely acquired.

[0041] Step 2: Gate acquisition and wave path difference calculation of the auxiliary channel

[0042] The auxiliary channel collects and processes the array echo data according to the main channel instruction. The steps for the auxiliary channel to calculate the wave path difference are as follows:

[0043] 1) The auxiliary channel performs gate acquisition on the array I and Q data transmitted by the optical fiber, and parses out the data within the range gate under each pulse according to the data protocol;

[0044] 2) Perform pulse compression processing on the data within the range gate;

[0045] 3) Perform modulus calculation on the data within the range gate;

[0046] 4) Select the point with the maximum amplitude from the data obtained by taking the modulus of the pulse compression within the range gate;

[0047] 5) Repeat steps 1) to 4) for each pulse within the azimuth gate;

[0048] 6) Select the point with the maximum value of the echo envelope within the gate;

[0049] 7) Calculate the phases of the echoes of each array element corresponding to the maximum value point within the gate;

[0050] 8) Perform amplitude-phase compensation on each receiving channel;

[0051] 9) Calculate the path difference of each array element relative to the first array element.

[0052] Step 3: Calculation of the incident angle of the auxiliary channel

[0053] Calculate the incident angle from the path difference:

[0054] θ = 2 * 180 * (d * sin(δ * pi / 180) / λ)

[0055] where θ is the incident angle, d is the element spacing, λ is the wavelength, and δ is the path difference.

[0056] Step 4: Evaluation of elevation deviation data

[0057] Match and compare the elevation estimates of the main channel and the calculated incident angle values of the auxiliary channel for the same batch of targets based on the target batch number and timestamp information. Repeat the above process to obtain the elevation deviation evaluation for the entire elevation coverage range. Intuitively display the elevation deviation data in the form of a graph with elevation (abscissa)_deviation (ordinate), and give an evaluation report.

Claims

1. An online elevation error estimation method for a phase-scanning array radar, characterized in that: Step 1: Master channel traction. The operator observes the display and control screen, selects a target that is isolated, flying towards the station, and whose echo amplitude meets the test conditions of the auxiliary channel, sends the target track information and gate size information to the auxiliary channel, and issues a gate acquisition command to the auxiliary channel; Step 2: Auxiliary channel target gate acquisition and wave path difference calculation; Step 3: The auxiliary channel calculates the incident angle. According to the distribution relationship of the wave path differences between the array radar elements, the incident angle is calculated from the wave path difference; Step 4: Elevation error estimation. Based on the time stamp, the elevation estimation value of the master channel is compared with the calculated value of the incident angle of the auxiliary channel to perform elevation error estimation.

2. An online elevation error estimation method for a phase-scanning array radar according to claim 1, characterized in that: The said Step 2 includes: 1) The auxiliary channel performs gate acquisition on the I and Q data of the array surface transmitted by the optical fiber, and analyzes the data within the range gate for each pulse according to the data protocol; 2) Perform pulse compression processing on the data within the range gate; 3) Take the modulus of the data within the range gate; 4) Select the maximum amplitude point from the data after taking the modulus of the pulse compression within the range gate; 5) Repeat 1)-4) for each pulse within the azimuth gate; 6) Select the maximum value point of the echo envelope within the gate; 7) Obtain the phases of the echoes of each element corresponding to the maximum value point within the gate; 8) Perform amplitude and phase compensation on each receiving channel; 9) Calculate the wave path differences of each element relative to the first element.

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