CN110058226B - Phased array radar angle measurement system based on positive and negative frequency modulation slope linear frequency modulation - Google Patents

Abstract

The present invention proposes a phased array radar angle measurement system based on positive and negative frequency modulation slope linear frequency modulation, wherein the radar reflected echo signals are sequentially received according to the time sequence of the signals transmitted by the pulse radar system; the echo signal weighting coefficients are generated The module calculates and obtains the echo signal weighting coefficients of each sub-array or array element of the phased array antenna according to the steering angle of the phased array antenna; the sum-difference channel echo generation module uses the echo signals of each sub-array or array element and the corresponding weighting The coefficient obtains the sum-difference channel echo; the echo signal processing module performs pulse compression on the sum-difference channel echo and detects the sum-difference channel complex signal at the distance where the target is located; the angle error calculation module measures the angle according to the amplitude ratio single pulse The method calculates the angle error values corresponding to the positive and negative frequency modulation slopes; the target angle calculation module calculates the angle of the target.

Description

A Phased Array Radar Angle Measurement System Based on Positive and Negative FM Slope Linear Frequency Modulation

technical field

The invention relates to the technical field of angle measurement of moving objects, in particular to a phased array radar angle measurement system based on positive and negative frequency modulation slope linear frequency modulation.

Background technique

Amplitude ratio monopulse angle measurement method is a widely used method in the field of radar angle measurement of moving targets, but this method is easily affected by angular flicker, which in turn affects the measurement accuracy of target angle. Therefore, in some applications that require high target angle measurement accuracy, it is necessary to improve the measurement frequency and accuracy of the target angle.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a phased array radar angle measurement system based on positive and negative frequency modulation slope linear frequency modulation, so as to solve the problem of low measurement frequency and precision of target angle.

In this regard, the present invention proposes a phased array radar angle measurement system based on positive and negative frequency modulation slope linear frequency modulation. The system includes: a radar echo acquisition module, an echo signal weighting coefficient generation module, and a difference channel echo generation module , an echo signal processing module, an angular error calculation module and a target angle calculation module; wherein, the radar reflected echo signals are sequentially received according to the time sequence of the signals transmitted by the pulse radar system; the echo signal weighting coefficient generation module is based on the phase control The echo signal weighting coefficient of each sub-array or array element of the phased array antenna is obtained by calculating the steering angle of the array antenna; the sum-difference channel echo generation module uses the echo signal of each sub-array or array element and the corresponding weighting coefficient to obtain the sum-difference channel channel echo; the echo signal processing module performs pulse compression on the sum-difference channel echo and detects the sum-difference channel complex signal at the distance of the target; The angle error value corresponding to the negative frequency modulation slope; the target angle calculation module calculates the angle of the target.

The beneficial effects of adopting the technical solution of the present invention:

In the case that the traditional method of single frequency modulation slope linear frequency modulation ratio amplitude single pulse angle measurement cannot meet the requirements of target angle measurement frequency and accuracy, the invention can use positive and negative frequency modulation slope linear frequency modulation to increase the phase without significantly reducing the radar repetition frequency. The measurement frequency of the target angle by the array radar, and the average of the two measurements is used to reduce the angular flicker effect encountered in the traditional method of single-pulse measurement. After theoretical derivation and simulation verification, the method can provide guidance for applications such as high-precision angle measurement of single or multiple moving targets.

Detailed ways

The technical solutions of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

Embodiments of the present invention are as follows:

(1) Build a phased array radar angle measurement system based on positive and negative frequency modulation slope linear frequency modulation;

Specifically, the phased array radar angle measurement system based on positive and negative frequency modulation slope linear frequency modulation includes: radar echo acquisition module, echo signal weighting coefficient generation module, sum-difference channel echo generation module, echo signal processing module, angle error a calculation module and a target angle calculation module; wherein,

The function of the radar echo acquisition module is to acquire the radar reflected echo of the target;

The function of the echo signal weighting coefficient generating module is to calculate the echo signal weighting coefficients of each sub-array (or array element) of the phased array antenna according to the steering angle of the phased array antenna;

The function of the sum-difference channel echo generation module is to obtain the sum-difference channel echo by using the echo signals of each sub-array (or array element) and the corresponding weighting coefficients;

The function of the echo signal processing module is: pulse compress the sum-difference channel echo and detect the sum-difference channel complex signal at the distance of the target;

The function of the angle error calculation module is to calculate the angle error value corresponding to the positive and negative frequency modulation slopes according to the amplitude ratio single pulse angle measurement method;

The function of the target angle calculation module is to calculate the angle of the target.

(2) The radar echo acquisition module acquires the radar reflection echo of the target;

Specifically, the pulse radar system transmits linear frequency modulation with a carrier frequency _fc in turn according to a certain pulse repetition period (PRT), and the frequency modulation slope alternates between positive and negative, and the radar echo acquisition module sequentially receives the signals transmitted by the pulse radar system in the time sequence. The radar reflected echo signals are denoted as R _up (t _τ ,n) and R _dn (t _τ ,n) respectively according to the sign of the signal FM slope, where R _up (t _τ ,n) represents the chirp slope direction as For a positive echo signal, R _dn (t _τ ,n) represents the echo signal with a negative chirp slope direction, t _τ is the time sequence of a single echo sampling, the so-called fast time, and n is the phased array antenna. The sequence number corresponding to the subarray (or array element).

(3) The echo signal weighting coefficient generation module calculates and obtains the echo signal weighting coefficients of each sub-array (or array element) of the phased array antenna according to the steering angle of the phased array antenna;

Specifically, the echo signal weighting coefficient generation module calculates the phased array antenna steering angle according to the array form of the phased array antenna used by the radar, the position and normal direction of each sub-array (or array element) and other parameters to obtain the phased array antenna steering angle as θ When the weighting coefficient of the sum channel echo signal of each sub-array (or array element) is denoted as the column vector W _s (n) of length N, and then the corresponding weighting coefficient of the difference channel echo signal is obtained, denoted as the length of N Column vector W _d (n). Among them, the coefficient of the sub-array (or array element) in the positive direction of the angle of W _d (n) is obtained by shifting the corresponding coefficient of W _s (n) by 90 degrees, and the sub-array of W _d (n) in the negative direction of the angle is obtained. The coefficients (or array elements) are obtained by shifting the corresponding coefficients of W _s (n) by negative 90 degrees.

(4) The sum-difference channel echo generation module obtains the sum-difference channel echo by using each sub-array (or array element) echo signal and the corresponding weighting coefficient;

Specifically, the sum-difference channel echo generation module uses the echo signals R _up (t _τ ,n) and R _dn (t _τ ,n) and the echo signal weighting coefficients W _s (n) and W _d (n) to respectively generate The sum-difference channel echo signal of positive and negative FM slopes, the specific operation formula is as follows:

和

分别表示正调频斜率和通道回波、正调频斜率差通道回波、负调频斜率和通道回波和负调频斜率差通道回波。in,

and

Respectively represent positive FM slope and channel echo, positive FM slope difference channel echo, negative FM slope and channel echo and negative FM slope difference channel echo.

(5) The echo signal processing module performs pulse compression on the sum-difference channel echo and detects the sum-difference channel complex signal at the distance where the target is located;

和

其中，

为目标所在距离处的正调频斜率和通道复信号，

为目标所在距离处的正调频斜率差通道复信号，

目标所在距离处的负调频斜率和通道复信号，

为目标所在距离处的负调频斜率差通道复信号。Specifically, the echo signal processing module performs pulse compression on the positive and negative FM slopes and the difference channel echoes, respectively, and finds the maximum value of the sum channel, and then obtains the corresponding complex signals at the distance of the difference channel target, which are respectively recorded as

and

in,

is the positive FM slope and the channel complex signal at the target distance,

is the positive FM slope difference channel complex signal at the distance of the target,

Negative FM slope and channel complex signal at the target distance,

is the negative FM slope difference channel complex signal at the target distance.

(6) The angle error calculation module calculates the angle error value corresponding to the positive and negative frequency modulation slopes according to the amplitude ratio single pulse angle measurement method;

Specifically, the angle error calculation module performs a single-pulse angle measurement operation on the positive and negative frequency modulation slopes and the corresponding complex signals at the distance where the difference channel target is located. The operation formula is as follows:

表示取

的实部，k为比例因子，sgn(x)为符号函数，定义为in,

means to take

The real part of , k is the scale factor, sgn(x) is the sign function, defined as

Similarly, δ _dn can be obtained.

(7) The target angle calculation module calculates the target angle.

Specifically, the target angle calculation module adds the average value of the current steering angle of the phased array radar antenna and the output value of the angle error calculation module to obtain the angle measurement value of the target, and the calculation formula is:

θ'=θ+(δ _up +δ _dn )/2

where θ' is the final angle measurement.

Obviously, the above-mentioned embodiments are only examples for clear description, rather than limiting the implementation manner. For those skilled in the art, changes or modifications in other different forms can also be made on the basis of the above description. There is no need and cannot be exhaustive of all implementations here. And the obvious changes or changes derived from this still belong to the protection scope of the present invention.

Claims (6)

1. a phased array radar angle measurement system based on positive and negative frequency modulation slope linear frequency modulation, is characterized in that, described system comprises: radar echo acquisition module, echo signal weighting coefficient generation module and difference channel echo generation module , an echo signal processing module, an angular error calculation module and a target angle calculation module; among them, The radar echo acquisition module sequentially receives the radar reflected echo signals according to the time sequence of the signals transmitted by the pulse radar system; The echo signal weighting coefficient generating module calculates and obtains the echo signal weighting coefficients of each sub-array or array element of the phased array antenna according to the steering angle of the phased array antenna; The sum-difference channel echo generation module obtains the sum-difference channel echo by using each sub-array or array element echo signal and the corresponding weighting coefficient; The echo signal processing module performs pulse compression on the sum-difference channel echo and detects the sum-difference channel complex signal at the distance where the target is located; The angular error calculation module calculates the angular error value corresponding to the positive and negative frequency modulation slopes according to the amplitude ratio single pulse angle measurement method; The target angle calculation module calculates the angle of the target, wherein the target angle calculation module performs an addition operation on the average value of the current steering angle of the phased array radar antenna and the output value of the angle error calculation module to obtain the angle measurement value of the target, The calculation formula is θ'=θ+(δ _up +δ _dn )/2 Among them, θ' is the final angle measurement value, θ is the current steering angle of the phased array antenna, δ _up , δ _dn are the positive and negative FM slopes and the relative amplitude monopulse angle measurement of the corresponding complex signal at the distance from the target of the difference channel, respectively . 2. the phased array radar angle measuring system based on positive and negative frequency modulation slope linear frequency modulation according to claim 1, is characterized in that, The pulse radar system transmits the linear frequency modulation with the carrier frequency _fc in turn according to a certain pulse repetition period PRT, and the frequency modulation slope alternates between positive and negative. The wave signal includes: according to the positive and negative signs of the frequency modulation slope of the signal, the echo signals are respectively recorded as R _up (t _τ ,n) and R _dn (t _τ ,n), where R _up (t _τ ,n) represents linear frequency modulation The echo signal with positive slope direction, R _dn (t _τ ,n) represents the echo signal with negative chirp slope direction, t _τ is the time series of single echo sampling, as fast time, n is the phased array antenna The sequence number corresponding to each subarray or array element, n is a natural number. 3. The phased array radar angle measurement system based on positive and negative frequency modulation slope linear frequency modulation according to claim 2, is characterized in that, described echo signal weighting coefficient generation module obtains phased array according to the steering angle calculation of phased array antenna The echo signal weighting coefficients of each sub-array or array element of the array antenna include: The echo signal weighting coefficient generation module calculates according to the array form of the phased array antenna used by the radar, the position and normal direction of each sub-array or array element, and obtains each sub-array or array when the steering angle of the phased-array antenna is θ. The weighting coefficient of the echo signal of the sum channel of the array element is denoted as a column vector W _s (n) of length N, and then the corresponding weighting coefficient of the difference channel echo signal is obtained, denoted as a column vector of length N W _d (n) ; Among them, the coefficients of the sub-arrays or array elements in the positive direction of the angle of W _d (n) are obtained by shifting the corresponding coefficients of W _s (n) by positive 90 degrees, and the sub-arrays or arrays of the sub-arrays or arrays in the negative direction of the angle of W _d (n) The coefficients of the elements are obtained by shifting the corresponding coefficients of W _s (n) by negative 90 degrees. 4. The phased array radar angle measurement system based on positive and negative frequency modulation slope linear frequency modulation according to claim 3, is characterized in that, described sum-difference channel echo generation module utilizes each sub-array or array element echo signal and corresponding The sum and difference channel echoes obtained by the weighting coefficients include: The sum-difference channel echo generation module uses the echo signals R _up (t _τ ,n) and R _dn (t _τ ,n) and the echo signal weighting coefficients W _s (n) and W _d (n) to generate positive The sum-difference channel echo signal with negative FM slope, the specific operation formula is as follows:

in,

and

Respectively represent positive FM slope and channel echo, positive FM slope difference channel echo, negative FM slope and channel echo, and negative FM slope difference channel echo. 5. The phased array radar angle measurement system based on positive and negative frequency modulation slope linear frequency modulation according to claim 4, wherein the echo signal processing module performs pulse compression on the sum-difference channel echo and detects the distance of the target The sum-difference channel complex signals at include: The echo signal processing module performs pulse compression on the positive and negative FM slopes and the difference channel echoes, respectively, and finds the maximum value of the sum channel, and then obtains the complex signal corresponding to the distance where the difference channel target is located, which are respectively recorded as

and

in

is the positive FM slope and the channel complex signal at the target distance,

is the positive FM slope difference channel complex signal at the distance of the target,

Negative FM slope and channel complex signal at the target distance,

is the negative FM slope difference channel complex signal at the target distance. 6. The phased array radar angle measuring system based on positive and negative frequency modulation slope linear frequency modulation according to claim 5, is characterized in that, described angular error calculation module calculates and obtains positive and negative frequency modulation slope corresponding to according to amplitude ratio monopulse angle measurement method The angular error values include: The angular error calculation module performs a single-pulse angular measurement operation on the positive and negative frequency modulation slopes and the corresponding complex signals at the distance of the difference channel target as follows:

in,

means to take

The real part of , k is the scale factor, sgn(x) is the sign function, defined as

Similarly, δ _dn can be obtained.