Sum-difference asymmetric monopulse angle measurement method
By adopting the sum-difference asymmetric single pulse angle measurement method in the radar system, using equivalent phase center vector calculation and optimization algorithm, the problem of inaccurate target angle estimation under asymmetric array conditions is solved, and high-precision unbiased angle measurement is achieved , improves radar performance.
Patent Information
- Application Number
- CN202411370441.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-29
- Publication Date
- 2025-02-11
AI Technical Summary
Under the conditions of asymmetric arrays, there are large deviations in single pulse and differential angle measurement methods in the existing radar systems, resulting in inaccurate target angle estimation and reducing the radar's performance.
Using the sum-to-difference asymmetric single pulse angle measurement method, through equivalent phase center vector calculation, a sum-to-difference angle measurement model based on the phase center of a two-dimensional plane array is established, and conventional algorithms are optimized to calculate the single pulse sum-to-difference ratio to determine the angle of the target object. .
It effectively solves the problem of asymmetric single pulse angle measurement of sum and difference, realizes high-precision unbiased estimation, improves radar target detection performance, and has a simple and convenient algorithm with great engineering application value.
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Figure CN119414346A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of radar detection target angle measurement, and in particular relates to a sum-difference asymmetric single pulse angle measurement method. Background Art
[0002] With the development of low-cost and modular radar TR components, a TR component often integrates multiple array elements. At the same time, due to the strict installation space restrictions of airborne radars, airborne active phased array radar antennas are developing towards irregular and asymmetric, making it difficult to form standard and differential beams. At this time, the target angle estimation has the following problems:
[0003] 1) Existing single pulse and differential angle measurement methods have large deviations
[0004] The conventional single pulse sum difference angle measurement method is based on the standard sum and difference beam theory. The asymmetry of the sum and difference introduces additional errors, which makes the conventional single pulse sum difference angle measurement theory invalid, and direct application will result in large deviations.
[0005] 2) The existing generalized monopulse angle measurement has a small linear region, and when the target deviates greatly from the center, there is a large deviation. For example, the generalized monopulse angle measurement can be directly applied to any form of sum-difference beam radar. However, the conventional generalized monopulse angle measurement is based on the first-order Tay l or approximation, and when the target deviates greatly from the center, there is a large deviation.
[0006] In summary, the radar has a large angle error in detecting the target, which reduces the performance of the radar. Summary of the invention
[0007] In view of this, the sum-difference asymmetric single pulse angle measurement method of the present invention solves the technical problem that the existing method reduces the use efficiency of the radar.
[0008] A sum-difference asymmetric single pulse angle measurement method is applicable to the angle measurement of a target by an aircraft radar, wherein the radar includes a phased array antenna, and the method includes:
[0009] S101: Calculate the equivalent phase center vector of the azimuth difference and elevation difference of the radar;
[0010] S102: establishing a single pulse sum difference angle measurement equation of the asymmetric array radar for the target based on the radar sum beam echo, azimuth difference beam number echo and elevation difference beam echo;
[0011] S103: Calculating a single pulse sum-difference ratio according to an actual echo signal of the target object detected by the radar;
[0012] S104: Determine the angle of the target object, which includes the azimuth angle Az t and pitch angle El t .
[0013] Beneficial Effects
[0014] Based on the equivalent phase center theory, the present invention establishes a sum-difference angle measurement model based on the phase center of a two-dimensional planar array and gives a theoretical exact solution. By optimizing and improving the conventional sum-difference angle measurement algorithm, the problem of sum-difference asymmetric single-pulse angle measurement is effectively solved. The algorithm is simple and convenient and has great engineering application value. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.
[0016] Figure 1 It is a schematic diagram of the process of the present invention;
[0017] Figure 2 Schematic diagram of the asymmetric array azimuth difference;
[0018] Figure 3 Schematic diagram of the asymmetric array pitch difference;
[0019] Figure 4 The method of the present invention and the difference angle measurement result;
[0020] Figure 5 The conventional method and the difference angle measurement results are shown in Figure 2. The arrows indicate the target angle estimation deviation. DETAILED DESCRIPTION
[0021] The embodiments of the present disclosure are described in detail below with reference to the accompanying drawings.
[0022] The following describes the embodiments of the present disclosure through specific examples, and those skilled in the art can easily understand other advantages and effects of the present disclosure from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all of the embodiments. The present disclosure can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present disclosure. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present disclosure.
[0023] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on the present disclosure, it should be understood by those skilled in the art that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects described herein can be used to implement the device and / or practice the method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this device and / or practice this method.
[0024] It should also be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present disclosure, and only show the components related to the present disclosure rather than being drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout type may also be more complicated.
[0025] Additionally, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, one skilled in the art will appreciate that aspects may be practiced without these specific details.
[0026] See also Figures 1 to 5 The sum-difference asymmetric single pulse angle measurement method shown is applicable to the angle measurement of a target by an aircraft radar, preferably, applicable to an active phased array radar, wherein the radar includes a phased array antenna, and the method includes:
[0027] S101: Calculate the equivalent phase center vector of the azimuth difference and elevation difference of the radar. Specifically,
[0028] S201: Calculating a difference equivalent phase center vector according to information parameters of the phased array antenna, where the information parameters include “sum and difference channel configuration”, array element coordinates, and array element low sidelobe weights;
[0029] S202: According to the x-axis coordinate x of the nth array element of the phased array antenna n , y-axis coordinate y n and the amplitude weighted value w of the nth array element n Determine the equivalent phase center vector, the equivalent phase center vector includes the pitch difference and the azimuth difference, the azimuth difference includes the first azimuth difference equivalent phase center d Az1 (that is, the left half of the antenna array) and the two-azimuth difference equivalent phase center d Az2 (that is, the right half of the antenna array), the elevation difference includes the first elevation difference equivalent phase center d El1 and the second pitch difference equivalent phase center d El2 , respectively expressed as:
[0030] Where, Arry_L represents the array element on the left side of the azimuth difference, and Arry_R represents the array element on the right side of the azimuth difference;
[0031] Where Arry_U represents the array element above the pitch difference, and Arry_D represents the array element below the pitch difference.
[0032] S102: Based on the radar's sum beam echo, azimuth difference beam echo and elevation difference beam echo, establish the single pulse "sum and difference angle measurement" equation of the asymmetric array radar for the target. Sum and difference angle measurement is a term. Specifically,
[0033] S301: Define u = sin (Az) cos (El), v = sin (El), when the radar receives the echo of the azimuth difference beam, the beam points to the azimuth component u0 and the pitch component v0, and the azimuth component u of the target echo t and the pitch component v t And the "sum beam" echo is S, which satisfies:
[0034]
[0035] S302: The “sum beam” echo is simplified to S: Where A is the amplitude of the target, λ is the wavelength of the electromagnetic wave, Az0 is the antenna electronic scanning azimuth, El0 is the antenna electronic scanning azimuth, Az t is the azimuth of the target, El t is the pitch angle of the target, j is the imaginary unit;
[0036] S303: Determine the azimuth phase difference of the target echo
[0037] Determine the azimuth component Δu of the target echo phase difference t = sin(Az t )cos(El t )-sin(Az0)cos(El0);
[0038] Determine the pitch component Δv of the target echo phase difference t = sin(El t )-sin(El0);
[0039] S304: Determine azimuth difference beam echo And determine the elevation difference beam echo D El =Aexp(-jΔθ t )-Aexp(jΔθ t ), where the pitch phase difference Δθ of the target echo t=(d El1 Δu t +d El2 Δv t )π / λ;
[0040] S305: The equation of the asymmetric array single pulse "sum and difference angle measurement" is obtained by the ratio of the azimuth difference beam echo, the elevation difference beam echo and the "sum beam" echo, which is expressed as:
[0041]
[0042] S103: Calculate the single pulse sum difference ratio according to the actual echo signal of the target object detected by the radar. Specifically,
[0043] According to the actual echo signal, obtain the actual and beam echo X S , actual azimuth difference beam echo and the actual elevation difference beam echo And calculate the azimuth and difference monopulse ratio and the pitch and difference monopulse ratio, where,
[0044] Azimuth and difference monopulse ratio
[0045] Pitch and difference monopulse ratio
[0046] S104: Determine the angle of the target object, which includes the azimuth angle Az t and pitch angle El t , specifically,
[0047] According to the equation of "sum and difference angle measurement" of asymmetric array single pulse, solve the azimuth component Δu of the target echo phase difference t The pitch component Δv of the phase difference between the target echo and the t ,satisfy:
[0048]
[0049] According to Δu t = sin(Az t )cos(El t )-sin(Az0)cos(El0) and Δv t = sin(El t )-sin(El0), the azimuth angle Az of the target object can be obtained t and pitch angle El t , expressed as:
[0050]
[0051] With the low-cost modular development of radar TR components, a TR component often integrates multiple array elements. At the same time, due to the stringent installation space restrictions of airborne radars, airborne active phased array radar antennas are developing towards irregular and asymmetric development, making it difficult to form standard sum and difference beams. At this time, the conventional sum and difference angle measurement algorithm will have a large deviation. In response to the above problems. The method of the present invention is based on the equivalent phase center theory and establishes a "sum and difference angle measurement" equation based on the phase center of a two-dimensional planar array. For example, according to the first azimuth difference equivalent phase center d Az1 , the second azimuth difference equivalent phase center d Az2 , the first pitch difference equivalent phase center d El1 and the second pitch difference equivalent phase center d El2 , can determine the angle of the target, ensure the high-precision angle measurement of the radar for the detected target, effectively solve the problem of sum and difference asymmetric single pulse angle measurement, the algorithm is simple and convenient, and has great engineering application value. The present invention is applicable to any form of active phased array antenna radar and difference asymmetric single pulse angle measurement, can achieve high-precision unbiased estimation, and is of great significance to improving the radar target detection performance.
[0052] For example:
[0053] Simulation parameters: electromagnetic wave frequency 10GHz, antenna form Figure 2 As shown, there are 36 array elements in azimuth and 16 array elements in elevation, the array element spacing is 0.5 times the wavelength, the low sidelobe weight is 30dB Taylor weight, the antenna azimuth electronic scanning angle is 30°, the elevation electronic scanning angle is 30°, the target deviates from the azimuth center between -1° and 1°, and deviates from the elevation center between -2° and 2°.
[0054] 1) Calculation of equivalent phase center vector of azimuth difference and elevation difference
[0055] According to the phased array antenna and difference configuration, phased array element coordinates and receiving element low sidelobe weights, the equivalent phase center vectors of azimuth difference and elevation difference are calculated. For any two-dimensional planar array, the x-axis coordinate of the nth array element is x n , the y-axis coordinate is y n , the receiving amplitude weight of the nth array element is w n The equivalent phase center vector of the azimuth difference is:
[0056]
[0057] Arry_L represents the array element on the left side of the azimuth difference, and Arry_R represents the array element on the right side of the azimuth difference.
[0058] The equivalent phase center vector of the pitch difference is:
[0059]
[0060] Arry_U represents the array element above the pitch difference, and Arry_D represents the array element below the pitch difference.
[0061] 2) Establish an asymmetric array single pulse and difference angle measurement equation. Based on the basic principle of active phased array radar, an asymmetric array single pulse and difference angle measurement model is established based on the sum beam echo, azimuth difference beam echo, and elevation difference beam echo, where:
[0062] Define u = sin(Az)cos(El), v = sin(El), when the azimuth difference beam is received, the beam points to u0, v0, and the target direction is u t 、v t The sum beam echo is S:
[0063]
[0064] in:
[0065]
[0066] Δu t = sin(Az t )cos(El t )-sin(Az0)cos(El0)
[0067] Δv t = sin(El t )-sin(El0)
[0068] A is the target amplitude, λ is the wavelength of the electromagnetic wave, Az0 is the antenna electronic scanning azimuth, El0 is the antenna electronic scanning azimuth, Az t is the azimuth of the target, El t is the pitch angle of the target.
[0069] The azimuth difference beam echo is:
[0070] The elevation difference beam echo is: D El =Aexp(-jΔθ t )-Aexp(jΔθ t );
[0071] Among them, Δθ t =(d El1 Δu t +d El2 Δv t )π / λ.
[0072] By calculating the ratio of the azimuth difference beam, elevation difference beam and sum beam echo, the asymmetric array single pulse sum difference angle measurement equation can be obtained as follows:
[0073]
[0074] 3) Calculate the actual target echo signal single pulse and difference ratio
[0075] According to the actual echo, target detection is performed to extract the target and beam complex echo X S , azimuth difference beam complex echo Elevation difference beam complex echo Calculate the single pulse sum-difference ratio.
[0076] The azimuth and difference monopulse ratio is:
[0077] The ratio of pitch and difference monopulse is:
[0078] 4) Solve and calculate the target angle
[0079] According to the asymmetric array single pulse and difference angle measurement equation, Δu can be directly solved t and Δv t The solution is:
[0080]
[0081] According to Δu t = sin(Az t )cos(El t )-sin(Az0)cos(El0) and Δv t = sin(El t )-sin(El0), the azimuth angle Az of the target can be directly solved t and pitch angle El t :
[0082]
[0083] Implementation effect:
[0084] Firstly, according to the phased array sky and difference configuration, the equivalent phase center vectors of azimuth difference and elevation difference are calculated, and the asymmetric array single pulse sum and difference angle measurement equation based on equivalent phase center theory is established; then, according to the actually detected target sum beam, azimuth difference beam and elevation difference beam signals, the single pulse sum and difference ratio of the actual echo is extracted; finally, according to the asymmetric array single pulse sum and difference angle measurement equation, the target angle is solved and calculated, and the sum and difference asymmetric single pulse unbiased angle measurement is realized. Figure 3 A comparison between the method of the present invention and conventional single pulse and differential angle measurement is given. It can be seen from the figure that for asymmetric arrays, conventional single pulse and differential angle measurement methods have large estimation errors. The more the target deviates from the beam center, the greater the error, which can reach up to 0.8°. The method of the present invention is almost an unbiased estimate, with a maximum error of <0.01°.
[0085] The above is only a specific implementation of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present disclosure should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.
Claims
1. A method for measuring angles by sum-difference asymmetric single pulses, suitable for measuring the angle of a target by a carrier radar, wherein the radar includes a phased array antenna, and is characterized in that: The methods include: S101: Calculate the equivalent phase center vector of the azimuth difference and elevation difference of the radar; S102: establishing a single pulse sum difference angle measurement equation of the asymmetric array radar for the target based on the radar sum beam echo, azimuth difference beam number echo and elevation difference beam echo; S103: Calculating a single pulse sum-difference ratio according to an actual echo signal of the target object detected by the radar; S104: Determine the angle of the target object, which includes the azimuth angle Az t and pitch angle El t .
2. The sum-difference asymmetric single pulse angle measurement method according to claim 1, characterized in that: S101 includes, S201: Calculating a difference equivalent phase center vector according to information parameters of the phased array antenna, wherein the information parameters include sum and difference channel configuration, array element coordinates, and array element low sidelobe weights; S202: According to the x-axis coordinate x of the nth array element of the phased array antenna n , y-axis coordinate y n and the amplitude weighted value w of the nth array element n Determine an equivalent phase center vector, wherein the equivalent phase center vector includes a pitch difference and an azimuth difference, wherein the azimuth difference includes a first azimuth difference equivalent phase center d Az1 and the equivalent phase center d of the two-azimuth difference Az2 , the pitch difference includes the first pitch difference equivalent phase center d El1 and the second pitch difference equivalent phase center d El2 , respectively expressed as: Where, Arry_L represents the array element on the left side of the azimuth difference, and Arry_R represents the array element on the right side of the azimuth difference; Where Arry_U represents the array element above the pitch difference, and Arry_D represents the array element below the pitch difference.
3. The sum-difference asymmetric single pulse angle measurement method according to claim 2, characterized in that: S102 includes: S301: Define u=sin(Az)cos(El), v=sin(El). When the radar receives the echo of the azimuth difference beam, the beam points to the azimuth component u0 and the elevation component v0, and the azimuth component u0 of the target echo. t and the pitch component v t The sum beam echo is S, which satisfies: S302: The sum beam echo is simplified to S: Where A is the target amplitude, λ is the wavelength of the electromagnetic wave, Az0 is the antenna electronic scanning azimuth, El0 is the antenna electronic scanning azimuth, Az t is the azimuth of the target, El t is the pitch angle of the target, j is the imaginary unit; S303: Determine the azimuth phase difference of the target echo Determine the azimuth component Δu of the target echo phase difference t = sin(Az t )cos(El t )-sin(Az0)cos(El0); Determine the pitch component Δv of the target echo phase difference t = sin(El t )-sin(El0); S304: Determine azimuth difference beam echo And determine the elevation difference beam echo D El =Aexp(-jΔθ t )-Aexp(jΔθ t ), where the pitch phase difference Δθ of the target echo t =(d El1 Δu t +d El2 Δv t )π / λ; S305: The equation of the asymmetric array single pulse and difference angle measurement is obtained by the ratio of the azimuth difference beam echo, the elevation difference beam echo and the sum beam echo, which is expressed as:
4. The method for measuring angles by sum-difference asymmetric single pulse according to claim 3, characterized in that: S103 includes: According to the actual echo signal, obtain the actual and beam echo X S 、Actual azimuth difference beam echo X DAz and the actual elevation difference beam echo X DEl , and calculate the azimuth and difference monopulse ratios and the elevation and difference monopulse ratios, where, Azimuth and difference monopulse ratio Pitch and difference monopulse ratio 5. The method for measuring angles by sum-difference asymmetric single pulse according to claim 4, characterized in that: S104 includes: According to the equation of the asymmetric array single pulse and difference angle measurement, the azimuth component Δu of the target echo phase difference is solved. t The pitch component Δv of the phase difference between the target echo and the t ,satisfy: According to Δu t = sin(Az t )cos(El t )-sin(Az0)cos(El0) and Δv t = sin(El t )-sin(El0), the azimuth angle Az of the target object can be obtained t and pitch angle El t , expressed as:
6. The sum-difference asymmetric single pulse angle measurement method according to claim 1, characterized in that: The radar is an active phased array radar.