A continuous wave phased array radar system with separate transmission and reception and its beam control method

Abstract

The present invention discloses a continuous wave phased array radar system with separate transmitters and receivers and a beam control method thereof. The system's array antenna structure layout selects a four-array structure layout, with each array covering a 90° range in azimuth, and the transmit and receive array surfaces are separated and arranged alternately at 45° intervals. The method comprises: determining the array azimuth scanning range in the phased array radar spatial coordinate system based on the array antenna structure layout; determining the optimal array surface tilt angle and array antenna geometric configuration based on the elevation scanning range in the phased array radar spatial coordinate system; determining the azimuth unit spacing and elevation unit spacing of the array antenna; determining the number of azimuth units and elevation units of the array antenna; determining the beam position arrangement in the sinusoidal spatial coordinate system; determining the beam distribution in the phased array radar spherical coordinate system; and controlling the amplitude and phase of the array antenna elements to form transmit and receive beams. The present invention solves the problem of continuous wave radar leakage signal suppression and improves the detection performance of continuous wave radar.

Description

Technical Field

[0001] The present invention relates to the technical field of radar system design, and in particular to a transmitting-receiving split continuous wave phased array radar system and a beam control method thereof. Background Art

[0002] Phased array radars can perform a variety of tasks, including target search, tracking, detection, and identification, and can simultaneously monitor and track multiple targets. Consequently, they have found widespread application in areas such as air defense surveillance and multi-target trajectory measurement. Traditional pulse-modulated phased array radars, which use magnetron transmitters, suffer from drawbacks such as bulk, low efficiency, and difficulty adjusting pulse width and modulation bandwidth.

[0003] In recent years, with the development of advanced solid-state device technology, active phased array radars using all-solid-state transmitters have achieved small size, light weight, high reliability, and low cost. Active phased array radars based on split-transmitter continuous-wave modulation can transmit flexible and variable high-duty-cycle waveforms, significantly reducing the radar's peak radiated power, achieving excellent low-obtain intercept performance, and eliminating range blind spots. The key to this is continuous-wave radar leakage signal suppression technology.

[0004] Currently, continuous wave radar leakage signal suppression uses RF cancellation and spatial isolation technologies. RF cancellation couples the transmitter's output signal as a cancellation signal to prevent strong leakage signals from saturating the radar's receiver front end. This technology only cancels the transmitted leakage signal and cannot suppress the transmitted signal's sideband noise. The transmitted signal sideband noise power N that leaks into the receiver is leak (dBW) can be expressed as N leak =P CW +η+B n -D g , where P CW (dBW) represents the transmitted signal power, η (dBc / Hz) represents the transmitted signal phase noise, B n (dBHz) represents the detection bandwidth, that is, the bandwidth of the sub-filter after Fourier transform, D g (dB) represents the isolation between the transmitting and receiving antennas. For example, when P CW =20dBW, η = -120dBc / Hz. To prevent the transmitted signal sideband noise from raising the receiver noise floor, the transmitted signal sideband noise power must be lower than the receiver noise power, that is, the requirement is: 20dBW-120dBc / Hz+B n -D g ≤-204dBW / Hz+B n , get D g≥104dB, indicating that the transmit and receive antenna isolation must be at least 104dB to meet system design requirements. Therefore, improving transmit and receive antenna isolation is key to suppressing continuous wave radar leakage signals. Existing continuous wave phased array radar systems suffer from low transmit and receive antenna isolation, which restricts the continuous wave radar's detection capabilities. Summary of the Invention

[0005] The purpose of the present invention is to provide a continuous wave phased array radar system with separate transmitters and receivers and a beam control method thereof, which utilizes transmitter and receiver array surfaces placed at 45° intervals to increase the spatial distance between the transmitter and receiver antennas, achieve high isolation between the transmitted and received signals, solve the problem of continuous wave radar leakage signal suppression, and improve the detection performance of the continuous wave radar.

[0006] The present invention adopts the following technical solution to solve the above technical problems: a continuous wave phased array radar system with separate transmitting and receiving arrays, wherein the array antenna structure layout of the system selects a four-array structure layout, each array azimuth covers a range of 90 degrees, and the transmitting and receiving arrays are separated, and the transmitting array and the receiving array are alternately arranged at an interval of 45 degrees;

[0007] The optimal array tilt angle and geometric configuration of the array antenna are determined according to the elevation scanning range in the spatial coordinate system of the phased array radar;

[0008] The azimuth unit spacing and elevation unit spacing of the array antenna are determined according to the optimal array tilt angle and the azimuth scanning range and elevation scanning range in the spatial coordinate system of the phased array radar;

[0009] The number of azimuth and elevation elements of the array antenna is determined based on the requirements for the azimuth and elevation element spacing of the array antenna, as well as the azimuth and elevation beamwidths.

[0010] The wave position arrangement in the sinusoidal space coordinate system is determined in the sinusoidal space coordinate system according to the sinusoidal space scanning area of the phased array radar;

[0011] The beam distribution in the spherical coordinate system of the phased array radar is determined in the spherical coordinate system of the phased array radar according to the wave position arrangement in the sinusoidal space coordinate system of the phased array radar;

[0012] The transmitting beam and receiving beam are formed by controlling the amplitude and phase of the array antenna units according to the beam distribution in the spherical coordinate system of the phased array radar.

[0013] A beam steering method for a continuous wave phased array radar system with separate transmitters and receivers is disclosed. The system's array antenna structure layout selects a four-array structure layout, with each array covering a 90° range. The transmitting and receiving arrays are separated, with the transmitting array and the receiving array alternately arranged at 45° intervals. The beam steering method steps are as follows:

[0014] Step 1: Determine the array azimuth scanning range in the phased array radar spatial coordinate system according to the array antenna structure layout;

[0015] Step 2: Determine the optimal array tilt angle and array antenna geometry according to the elevation scanning range in the phased array radar spatial coordinate system;

[0016] Step 3: Determine the sinusoidal spatial scanning area of the phased array radar and the azimuth unit spacing and elevation unit spacing of the array antenna based on the optimal array tilt angle determined in step 2 and the azimuth scanning range and elevation scanning range in the phased array radar spatial coordinate system;

[0017] Step 4: Determine the number of azimuth and elevation elements of the array antenna according to the azimuth element spacing and elevation element spacing of the array antenna and the requirements for azimuth beamwidth and elevation beamwidth determined in step 3;

[0018] Step 5: Determine the wave position arrangement in the sinusoidal space coordinate system according to the sinusoidal space scanning area of the phased array radar determined in step 3;

[0019] Step 6: Determine the beam distribution in the phased array radar spherical coordinate system according to the arranged wave position determined in the phased array radar sinusoidal space coordinate system in step 5;

[0020] Step 7: Based on the beam distribution in the spherical coordinate system of the phased array radar in step 6, the amplitude and phase of the array antenna unit are controlled to form the transmit beam and the receive beam.

[0021] Compared with the prior art, the present invention has the following significant advantages:

[0022] (1) High isolation between the transmitting and receiving antennas: The transmitting and receiving arrays are placed at 45° intervals and staggered in elevation, achieving large-spacing spatial isolation within a limited space. Choke slots and absorbing materials can be flexibly placed between the transmitting and receiving antennas to further improve isolation between them, thus resolving the issue of continuous wave radar detection capability being limited by the isolation between the transmitting and receiving antennas.

[0023] (2) Reduce the fluctuation of two-way beam scanning loss: During the scanning process, the greater the scanning angle deviates from the array normal, the greater the beam scanning loss. In the traditional coplanar transceiver array, the two-way beam scanning loss is twice the one-way beam scanning loss, resulting in a beam loss of about 3 to 4 dB greater than the normal direction at scanning angles away from the array normal. In this method, the transceiver beams are complementary at 45°, and the beam loss fluctuation is about 0.8 to 1 dB, which can ensure that the beam obtains a relatively constant detection power within the scanning range, which is beneficial to the detection of tangentially moving targets. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1It is the overall flow chart of the present invention.

[0025] Figure 2 This is a structural layout diagram of the array antenna used in the present invention.

[0026] Figure 3 It is a geometric model diagram of the antenna array used in the present invention in a Cartesian coordinate system.

[0027] Figure 4 It is the three-dimensional beam pattern in the array normal direction obtained by the method of the present invention.

[0028] Figure 5 It is an arranged wave position diagram determined in the sinusoidal space coordinate system of the phased array radar obtained by the method of the present invention.

[0029] Figure 6 It is the beam pointing diagram of the phased array radar in the sinusoidal space coordinate system obtained by the method of the present invention.

[0030] Figure 7 It is the beam pointing diagram of the phased array radar in the space coordinate system obtained by the method of the present invention.

[0031] Figure 8 It is the transmitting beam and receiving beam pointing diagram of the phased array radar in the sinusoidal space coordinate system obtained by the method of the present invention.

[0032] Figure 9 This is a scanning loss diagram generated during the phased array radar beam scanning process obtained by the method of the present invention. DETAILED DESCRIPTION

[0033] To address the issue of low isolation between transmit and receive antennas, the present invention employs bi-located transmit and receive antennas to improve the isolation between transmitted and received signals. The key to this is increasing the spatial separation between the transmit and receive antennas. Therefore, an active phased array radar system is designed with transmit and receive arrays spaced 45° apart. When the antenna arrays are fixed, transmit and receive beam steering is crucial for achieving spatial scanning of phased array radars. Therefore, the present invention also designs a beam steering method for bi-located continuous-wave phased array radar systems.

[0034] The present invention provides a continuous wave phased array radar system with separate transmitting and receiving arrays. The system has an array antenna structure layout of four arrays, each array covering a 90° range, and the transmitting and receiving arrays are separated, with the transmitting array and the receiving array alternately arranged at 45° intervals.

[0035] The optimal array tilt angle and geometric configuration of the array antenna are determined according to the elevation scanning range in the spatial coordinate system of the phased array radar;

[0036] The azimuth unit spacing and elevation unit spacing of the array antenna are determined according to the optimal array tilt angle and the azimuth scanning range and elevation scanning range in the spatial coordinate system of the phased array radar;

[0037] The number of azimuth and elevation elements of the array antenna is determined based on the requirements for the azimuth and elevation element spacing of the array antenna, as well as the azimuth and elevation beamwidths.

[0038] The wave position arrangement in the sinusoidal space coordinate system is determined in the sinusoidal space coordinate system according to the sinusoidal space scanning area of the phased array radar;

[0039] The beam distribution in the spherical coordinate system of the phased array radar is determined in the spherical coordinate system of the phased array radar according to the wave position arrangement in the sinusoidal space coordinate system of the phased array radar;

[0040] The transmitting beam and receiving beam are formed by controlling the amplitude and phase of the array antenna units according to the beam distribution in the spherical coordinate system of the phased array radar.

[0041] As a specific example, the azimuth scanning range of each array in the phased array radar spatial coordinate system is az = [-45°, 45°]. With the normal direction of transmitting array 1 as 0° and the clockwise direction as positive, the azimuth scanning area of transmitting array 1 is (315°, 360°) and (315°, 45°), the azimuth scanning area of transmitting array 2 is (45°, 135°), the azimuth scanning area of transmitting array 3 is (135°, 225°), and the azimuth scanning area of transmitting array 4 is (225°, 315°); the receiving array surface is staggered by 45° compared to the transmitting array surface, the azimuth scanning area of receiving array 1 is (0°, 90°), the azimuth scanning area of receiving array 2 is (90°, 180°), the azimuth scanning area of receiving array 3 is (180°, 270°), and the azimuth scanning area of receiving array 4 is (270°, 360°).

[0042] As a specific example, the optimal array tilt angle and geometric configuration of the array antenna are determined by the following process:

[0043] The elevation scanning range of the phased array radar in the spatial coordinate system is el. In order to minimize the maximum scanning angle of the beam within the given scanning range, the optimal array tilt angle is determined to meet where el max Indicates the maximum scanning angle in pitch direction, el min Indicates the minimum scanning angle in pitch direction;

[0044] The geometric configuration of the array antenna adopts a rectangular grid, and the antenna units are arranged at equal intervals.

[0045] As a specific example, the azimuth unit spacing and the elevation unit spacing of the array antenna are determined by the following process:

[0046] According to the conversion formula from the phased array radar space coordinate system to the sinusoidal space coordinate system, the sinusoidal space scanning area of the phased array radar is determined:

[0047] α=cos(el)×sin(az)

[0048] β=sin(el)×cos(θ T )-cos(el)×cos(az)×sin(θ T )

[0049] Where α represents the sinusoidal spatial horizontal coordinate of the phased array radar, β represents the sinusoidal spatial vertical coordinate; az and el are the azimuth scanning range and elevation scanning range in the spatial coordinate system of the phased array radar respectively; θ T is the optimal array inclination angle;

[0050] Referring to the geometric model of the array antenna in the Cartesian coordinate system, the array antenna is arranged in the xy plane, and the azimuth unit spacing of the array antenna is recorded as d x , according to the condition that no grating lobe appears within the azimuth scanning range, the azimuth unit spacing is determined to meet where λ min Indicates the minimum operating wavelength;

[0051] The pitch unit spacing of the array antenna is denoted as d y , according to the condition that no grating lobe appears within the pitch scanning range, the pitch unit spacing is determined to meet

[0052] As a specific example, the number of azimuth units and the number of elevation units of the array antenna are determined by the following process:

[0053] According to the determined azimuth unit spacing and azimuth beam width requirements, the number of azimuth units of the array antenna N is s satisfy where λ max Indicates the maximum operating wavelength, θ 3dB Indicates the 3dB beamwidth in azimuth;

[0054] According to the determined pitch unit spacing and pitch beam width requirements, the number of pitch units of the array antenna M is s satisfy Indicates the 3dB beamwidth in elevation.

[0055] As a specific example, the wave position arrangement in the sinusoidal space coordinate system uses an interleaved beam arrangement method, with 3dB beam width intervals in azimuth and 2.2dB beam width intervals in elevation. The coordinates of the arranged wave position in the sinusoidal space coordinate system (αij ,β ij ), where α ij represents the sinusoidal spatial coordinate of the jth wave position in the i-th row, β ij represents the sinusoidal spatial ordinate of the j-th wave position in the i-th row;

[0056] Phased array radar beam pointing in spherical coordinate system for:

[0057]

[0058]

[0059] where θ ij represents the azimuth pointing direction of the jth beam in the i-th row in the spherical coordinate system of the phased array radar, represents the pitch pointing direction of the jth beam in the i-th row;

[0060] Phased array radar beam pointing in space coordinate system (az ij ,el ij )for:

[0061]

[0062]

[0063] Among them az ij Indicates the azimuth pointing direction of the jth beam in the i-th row in the phased array radar space coordinate system, el ij Indicates the pitch pointing direction of the jth beam in the i-th row.

[0064] As a specific example, the transmit beam and the receive beam are formed by controlling the amplitude and phase of the array antenna units according to the beam distribution in the spherical coordinate system of the phased array radar, wherein:

[0065] The phase control of the transmitting array antenna unit is:

[0066]

[0067] in,

[0068]

[0069]

[0070] n=0,1,…,N s -1 indicates the nth row of antenna elements, N s Indicates the number of antenna units in azimuth, m=0,1,…,M s -1 indicates the mth column antenna unit, M s Indicates the number of antenna units in elevation direction;

[0071] The phase control of the receiving array antenna unit is:

[0072]

[0073] in,

[0074]

[0075]

[0076]

[0077]

[0078]

[0079]

[0080] θ T Indicates the optimal array inclination angle.

[0081] The present invention provides a beam control method for a continuous wave phased array radar system with separate transmitting and receiving arrays. The system's array antenna structure layout selects a four-array structure layout, each array covers a 90° range, and the transmitting and receiving arrays are separated, with the transmitting array and the receiving array alternately arranged at 45° intervals. The beam control method steps are as follows:

[0082] Step 1: Determine the array azimuth scanning range in the phased array radar spatial coordinate system according to the array antenna structure layout;

[0083] Step 2: Determine the optimal array tilt angle and array antenna geometry according to the elevation scanning range in the phased array radar spatial coordinate system;

[0084] Step 3: Determine the sinusoidal spatial scanning area of the phased array radar and the azimuth unit spacing and elevation unit spacing of the array antenna based on the optimal array tilt angle determined in step 2 and the azimuth scanning range and elevation scanning range in the phased array radar spatial coordinate system;

[0085] Step 4: Determine the number of azimuth and elevation elements of the array antenna according to the azimuth element spacing and elevation element spacing of the array antenna and the requirements for azimuth beamwidth and elevation beamwidth determined in step 3;

[0086] Step 5: Determine the wave position arrangement in the sinusoidal space coordinate system according to the sinusoidal space scanning area of the phased array radar determined in step 3;

[0087] Step 6: Determine the beam distribution in the phased array radar spherical coordinate system according to the arranged wave position determined in the phased array radar sinusoidal space coordinate system in step 5;

[0088] Step 7: Based on the beam distribution in the spherical coordinate system of the phased array radar in step 6, the amplitude and phase of the array antenna unit are controlled to form the transmit beam and the receive beam.

[0089] As a specific example, in step 5, the beam arrangement method uses staggered beams, with 3dB beam width intervals in azimuth and 2.2dB beam width intervals in elevation, and the coordinates of the arranged beam positions in the sinusoidal space coordinate system (α ij ,β ij ), where α ij represents the sinusoidal spatial coordinate of the jth wave position in the i-th row, β ij Represents the sinusoidal space ordinate of the j-th wave position in the i-th row.

[0090] As a specific example, step 7 is as follows:

[0091] (7.1) The amplitude and phase of the transmit array antenna unit are controlled to complete transmit beam synthesis in space and form a transmit beam. The phase control formula of the transmit array antenna unit is as follows:

[0092]

[0093] in,

[0094]

[0095]

[0096] n=0,1,…,N s -1 indicates the nth row of antenna elements, N s Indicates the number of antenna units in azimuth, m=0,1,…,M s -1 indicates the mth column antenna unit, M s Indicates the number of antenna units in elevation direction;

[0097] (7.2) The amplitude and phase of the receiving array antenna unit are controlled to form a receiving beam at the receiving end of the array antenna. The phase control formula of the receiving array antenna unit is as follows:

[0098]

[0099] in,

[0100]

[0101]

[0102]

[0103]

[0104]

[0105]

[0106] θ T Indicates the optimal array inclination angle.

[0107] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those skilled in the art in the art to which the present invention belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with their meanings in the context of the prior art and, unless defined as such, will not be interpreted in an idealized or overly formal sense.

[0108] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be interpreted as limiting the present invention.

[0109] Example

[0110] The present invention provides a continuous wave phased array radar system with separate transmitting and receiving locations and a beam control method thereof, wherein the implementation steps are as follows: Figure 1 shown.

[0111] Step 1: Determine the array azimuth scanning range in the phased array radar spatial coordinate system based on the array antenna structure layout.

[0112] (1.1) Detecting sea / ground and low-altitude targets, with a 360° all-round search, a four-array structure is selected to reduce aperture loss and antenna unit mismatch. Each array azimuth covers a 90° range, that is, the array azimuth scanning range in the phased array radar spatial coordinate system is az = [-45°, 45°];

[0113] (1.2)Reference Figure 2The transmitting and receiving arrays are separated and placed 45° apart. With the normal direction of transmitting array 1 at 0° and the clockwise direction as positive, the azimuth scanning area of transmitting array 1 is (315°, 360°) and (315°, 45°), the azimuth scanning area of transmitting array 2 is (45°, 135°), the azimuth scanning area of transmitting array 3 is (135°, 225°), and the azimuth scanning area of transmitting array 4 is (225°, 315°). The receiving array is staggered 45° from the transmitting array. The azimuth scanning area of receiving array 1 is (0°, 90°), the azimuth scanning area of receiving array 2 is (90°, 180°), the azimuth scanning area of receiving array 3 is (180°, 270°), and the azimuth scanning area of receiving array 4 is (270°, 360°).

[0114] Step 2: Determine the optimal array tilt angle and array antenna geometric configuration based on the pitch scanning range in the phased array radar spatial coordinate system.

[0115] (2.1) Let the elevation scanning range of the phased array radar in the spatial coordinate system be el. In order to minimize the maximum scanning angle of the beam within a given scanning range, determine the optimal array tilt angle to satisfy where el max Indicates the maximum scanning angle in pitch direction, el min Indicates the minimum scanning angle in pitch direction;

[0116] (2.2) The geometric configuration of the array antenna is a rectangular grid, with the antenna units arranged at equal intervals.

[0117] Step 3: According to the optimal array inclination angle θ determined in step 2 T As well as the azimuth scanning range az and elevation scanning range el in the phased array radar space coordinate system, determine the azimuth unit spacing and elevation unit spacing of the array antenna.

[0118] (3.1) According to the conversion formula from the phased array radar spatial coordinate system to the sinusoidal spatial coordinate system, the sinusoidal spatial scanning area of the phased array radar is determined. The solution steps are as follows:

[0119] α=cos(el)×sin(az)

[0120] β=sin(el)×cos(θ T )-cos(el)×cos(az)×sin(θ T )

[0121] Where α represents the sinusoidal space abscissa of the phased array radar, and β represents the sinusoidal space ordinate;

[0122] (3.2)Reference Figure 3The geometric model of the array antenna in the Cartesian coordinate system. The array antenna is arranged in the xy plane, and the azimuth unit spacing of the array antenna is recorded as d x According to the condition that no grating lobes appear within the azimuth scanning range, the azimuth unit spacing is determined to meet where λ min Indicates the minimum operating wavelength;

[0123] (3.3) The pitch element spacing of the array antenna is denoted as d y , according to the condition that no grating lobe appears within the pitch scanning range, the pitch unit spacing is determined to meet

[0124] Step 4: Determine the number of azimuth and elevation elements of the array antenna based on the azimuth element spacing and elevation element spacing of the array antenna and the requirements for the azimuth beamwidth and elevation beamwidth determined in step 3.

[0125] (4.1) According to the azimuth unit spacing and azimuth beamwidth requirements determined in step (3.2), the number of azimuth units of the array antenna meets where λ max Indicates the maximum operating wavelength, θ 3dB Indicates the 3dB beamwidth in azimuth;

[0126] (4.2) According to the pitch unit spacing and pitch beam width requirements determined in step (3.3), the number of pitch units of the array antenna meets Indicates the 3dB beamwidth in elevation.

[0127] Step 5: Based on the sinusoidal spatial scanning area of the phased array radar determined in step (3.1), determine the wave position arrangement in the sinusoidal spatial coordinate system, specifically:

[0128] (5.1) Minimize the pitch scanning angle and change the azimuth scanning angle to obtain the lower boundary of the sinusoidal spatial scanning area of the phased array radar and determine the minimum value of the lower boundary β min =min(sin(el min )×cos(θ T )-cos(el min )×cos(az)×sin(θ T ), the minimum value of the left boundary α min =min(cos(el min )×sin(az)), the maximum value of the right boundary α max =max(cos(el min )×sin(az)), where min(·) indicates the minimum value and max(·) indicates the maximum value;

[0129] (5.2) Let the pitch scanning angle be the largest and the azimuth scanning angle change to obtain the upper boundary of the sinusoidal spatial scanning area of the phased array radar and determine the maximum value of the upper boundary β max =max(sin(el max )×cos(θ T )-cos(el max )×cos(az)×sin(θ T ));

[0130] (5.3) The number of beams to be arranged is determined based on the scanning area boundaries determined in steps (5.1) and (5.2). The solution steps are as follows:

[0131] (5.3a) The beam arrangement method uses staggered beams, with 3dB beamwidth intervals in azimuth and 2.2dB beamwidth intervals in elevation;

[0132] (5.3b) The wave positions are arranged starting from the lower boundary of the scanning area, which is recorded as the first wave position. The maximum number of wave position rows is determined as Where round(·) means rounding to the nearest integer;

[0133] (5.3c) is arranged in odd-numbered wave positions, and the vertical coordinate is Where i≤row, i=1,3,… represents odd rows, and the horizontal coordinate is initially selected as In α min and α max The interval θ 3dB Arrange left and right;

[0134] (5.3d) Arrange the even-numbered wave positions, and the vertical coordinate is Where i≤row, i=2,4,… represents an even row, the horizontal coordinate is initially selected as 0, and in α min and α max The interval θ 3dB Arranged left and right.

[0135] Step 6: Based on the arranged beam positions determined in the phased array radar sinusoidal space coordinate system in step 5, determine the beam distribution in the phased array radar spherical coordinate system. The solution steps are as follows:

[0136] Note that the arrangement wave position determined in the sinusoidal space coordinate system of the phased array radar in step 5 is (α ij ,β ij ), where i = 1, 2, ... represents the i-th row, j = 1, 2, ... represents the j-th wave position, then the beam pointing in the spherical coordinate system of the phased array radar is for:

[0137]

[0138]

[0139] where θ ij represents the azimuth pointing direction of the jth beam in the i-th row in the spherical coordinate system of the phased array radar, Indicates the pitch pointing direction of the jth beam in the i-th row.

[0140] Phased array radar beam pointing in space coordinate system (az ij ,el ij )for:

[0141]

[0142]

[0143] Among them az ij Indicates the azimuth pointing direction of the jth beam in the i-th row in the phased array radar space coordinate system, el ij Indicates the pitch pointing direction of the jth beam in the i-th row.

[0144] Step 7: Based on the beam distribution of the phased array radar in the spherical coordinate system in step 6, the amplitude and phase of the array antenna elements are controlled to form a transmit beam and a receive beam, which specifically includes:

[0145] (7.1) Control the amplitude and phase of the transmit array antenna elements to complete transmit beam synthesis in space and form a transmit beam;

[0146] Reference Figure 3 , taking the array antenna unit at position (0,0) as the reference unit, the phase of the array antenna unit at position (n,m) is controlled as follows:

[0147]

[0148] where n=0,1,…,N s -1 represents the nth column antenna unit, m=0,1,…,M s -1 represents the mth row of antenna elements. The spatially synthesized transmit beam is:

[0149]

[0150] Where Y represents the transmit frequency-beam response function, f(w) represents the spectrum of the transmit signal, and A nm Represents the signal amplitude weighting of the transmitting array antenna unit.

[0151] (7.2) Control the amplitude and phase of the receiving array antenna elements to form a receiving beam at the receiving end of the array antenna;

[0152] Since the transmitting and receiving arrays are placed at 45° intervals, the azimuth beam pointing is staggered by 45° for reception. The phase of the receiving array antenna unit at the (n, m) position is controlled as follows:

[0153]

[0154] in

[0155]

[0156]

[0157]

[0158]

[0159] The synthesized receive beam is:

[0160]

[0161] Where Y′ represents the receiving frequency-beam response function, f′(w) represents the spectrum of the echo signal, and A n ' m Represents the amplitude weighting of the receiving array antenna unit signal.

[0162] The effect of the present invention is further illustrated by the following simulation experiments:

[0163] 1. Experimental conditions: According to the requirements of a certain X-band wideband digital array radar, the azimuth scanning range is -45° to 45°, the elevation scanning range is 0° to 30°, the azimuth beamwidth in the array normal direction is ≤3.5°, and the elevation beamwidth is ≤5.5°. A uniform rectangular array is selected, the array inclination angle is 10°, the number of azimuth elements is 32, and the element spacing is selected as 0.56λ. min , the number of pitch units is 16, and the unit spacing is selected as 0.7λ min , where λ min Indicates the minimum operating wavelength.

[0164] 2. Simulation content:

[0165] Simulation 1, based on the above simulation parameters, Figure 4 The three-dimensional beam pattern in the normal direction of the array obtained by the method of the present invention is given. The 3dB beam width in azimuth is 2.9°, and the 3dB beam width in elevation is 4.64°, which meets the index requirements. Wherein, the x-axis represents the sinusoidal spatial horizontal coordinate, The y-axis represents the ordinate of the sinusoidal space, The z-axis represents the sinusoidal spatial normalized beam gain.

[0166] Simulation 2, based on the above simulation parameters, Figure 5The arrangement wave position determined in the sinusoidal space coordinate system of the phased array radar obtained by the method of the present invention is given. Figure 6 The beam pointing of the phased array radar in the sinusoidal space coordinate system obtained by the method of the present invention is given. Figure 7 The beam pointing patterns of the phased array radar in the spatial coordinate system obtained using the method of the present invention are shown. To reduce the number of programmed beam positions and save time and resources, beam positions with beam pointing outside the scanning airspace are eliminated. As can be seen from the figure, the programmed beam positions using the method of the present invention can cover the required airspace, demonstrating the correctness and feasibility of the proposed method.

[0167] Simulation 3, based on the above simulation parameters, taking the transmit beam spatial azimuth scanning range [0°, 45°] as an example, the corresponding receive beam spatial azimuth scanning range is [-45°, 0°]. Figure 8 The transmitting beam and receiving beam pointing of the phased array radar in the sinusoidal space coordinate system obtained by the method of the present invention are given, where * represents the transmitting beam pointing and o represents the receiving beam pointing.

[0168] Simulation 4, based on the above simulation parameters, Figure 9 The scanning loss generated during the beam scanning process of a phased array radar obtained by the method of the present invention is shown. As can be seen from the figure, the scanning loss fluctuates between 0.7dB and 1.6dB, with a fluctuation range of 0.9dB. For comparison, the scanning loss generated during the beam scanning process of a traditional coplanar transceiver array is also shown in the figure. As can be seen from the figure, the scanning loss fluctuates between 0 and 3dB, with a fluctuation range of 3dB. Therefore, the method of the present invention can effectively reduce the fluctuation of the two-way beam scanning loss, ensure that the beam obtains relatively constant detection power within the scanning range, and facilitate the detection of tangentially moving targets.

[0169] The present invention discloses a continuous wave phased array radar system with separate transmitters and receivers and a beam control method thereof, which mainly solves the problem of reduced detection power due to signal leakage in existing continuous wave radars. The implementation steps are as follows: 1. Determining the array azimuth scanning range in the phased array radar space coordinate system according to the array antenna structure layout, selecting a four-array structure layout, and arranging the transmitting array face and the receiving array face at a 45° interval; 2. Determining the optimal array face inclination angle and array antenna geometric configuration according to the elevation scanning range in the phased array radar space coordinate system, and selecting a rectangular grid; 3. Determining the azimuth unit spacing and elevation unit spacing of the array antenna; 4. Determining the number of azimuth units and elevation units of the array antenna; 5. Determining the wave position arrangement in the sinusoidal space coordinate system; 6. Determining the beam distribution in the phased array radar spherical coordinate system; 7. Controlling the amplitude and phase of the array antenna elements to form the transmitting beam and the receiving beam.

[0170] The present invention utilizes transceiver arrays placed at 45° intervals to increase the spatial distance between transceiver antennas, achieving high isolation between transmitted and received signals. This solves the problem that the detection capability of continuous wave radar is restricted by the isolation of transceiver antennas, improves the detection power of continuous wave radar, and combines pulse compression signal processing technology to achieve high signal processing gain, thereby obtaining long-range target detection performance. At the same time, it can effectively reduce the loss fluctuation of two-way beam scanning, which is beneficial to the detection of tangentially moving targets. The present invention can be widely used in three-coordinate radars such as air and sea surveillance and battlefield reconnaissance.

[0171] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be understood and conceived by anyone familiar with the art within the technical scope disclosed by the present invention are intended to be included within the scope of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A continuous wave phased array radar system with bi-directional transmission and reception, characterized in that: The system's array antenna structure layout uses a four-array structure layout, with each array covering a 90° range, and the transmitting and receiving arrays are separated, with the transmitting array and the receiving array alternately set at 45° intervals; The optimal array tilt angle and geometric configuration of the array antenna are determined according to the elevation scanning range in the spatial coordinate system of the phased array radar; The azimuth unit spacing and elevation unit spacing of the array antenna are determined according to the optimal array tilt angle and the azimuth scanning range and elevation scanning range in the spatial coordinate system of the phased array radar; The number of azimuth and elevation elements of the array antenna is determined based on the requirements for the azimuth and elevation element spacing of the array antenna, as well as the azimuth and elevation beamwidths. The wave position arrangement in the sinusoidal space coordinate system is determined in the sinusoidal space coordinate system according to the sinusoidal space scanning area of the phased array radar; The beam distribution in the spherical coordinate system of the phased array radar is determined in the spherical coordinate system of the phased array radar according to the wave position arrangement in the sinusoidal space coordinate system of the phased array radar; The transmitting beam and receiving beam are formed by controlling the amplitude and phase of the array antenna units according to the beam distribution in the spherical coordinate system of the phased array radar.

2. The transmitting and receiving bi-located continuous wave phased array radar system according to claim 1, characterized in that: The azimuth scanning range of each array in the phased array radar spatial coordinate system is az = [-45°, 45°]. With the normal direction of transmitting array 1 as 0° and the clockwise direction as positive, the azimuth scanning area of transmitting array 1 is (315°, 360°) and (315°, 45°), the azimuth scanning area of transmitting array 2 is (45°, 135°), the azimuth scanning area of transmitting array 3 is (135°, 225°), and the azimuth scanning area of transmitting array 4 is (225°, 315°); the receiving array surface is staggered by 45° compared to the transmitting array surface, the azimuth scanning area of receiving array 1 is (0°, 90°), the azimuth scanning area of receiving array 2 is (90°, 180°), the azimuth scanning area of receiving array 3 is (180°, 270°), and the azimuth scanning area of receiving array 4 is (270°, 360°).

3. The transmitting and receiving bi-located continuous wave phased array radar system according to claim 1, characterized in that: The optimal array tilt angle and geometric configuration of the array antenna are determined by the following process: The elevation scanning range of the phased array radar in the spatial coordinate system is el. In order to minimize the maximum scanning angle of the beam within the given scanning range, the optimal array inclination angle is determined to satisfy where el max Indicates the maximum scanning angle in the pitch direction, el min Indicates the minimum scanning angle in pitch direction; The geometric configuration of the array antenna adopts a rectangular grid, and the antenna units are arranged at equal intervals.

4. The transmitting and receiving bi-located continuous wave phased array radar system according to claim 3, characterized in that: The azimuth unit spacing and elevation unit spacing of the array antenna are determined by the following process: According to the conversion formula from the phased array radar space coordinate system to the sinusoidal space coordinate system, the sinusoidal space scanning area of the phased array radar is determined: α=cos(el)×sin(az) β=sin(el)×cos(θ T )-cos(el)×cos(az)×sin(θ T ) Where α represents the sinusoidal spatial horizontal coordinate of the phased array radar, β represents the sinusoidal spatial vertical coordinate; az and el are the azimuth scanning range and elevation scanning range in the spatial coordinate system of the phased array radar respectively; θ T is the optimal array inclination angle; Referring to the geometric model of the array antenna in the Cartesian coordinate system, the array antenna is arranged in the xy plane, and the azimuth unit spacing of the array antenna is recorded as d x , according to the condition that no grating lobe appears within the azimuth scanning range, the azimuth unit spacing is determined to meet where λ min Indicates the minimum operating wavelength; The pitch unit spacing of the array antenna is denoted as d y , according to the condition that no grating lobe appears within the pitch scanning range, the pitch unit spacing is determined to meet 5. The transmitting and receiving bi-located continuous wave phased array radar system according to claim 4, characterized in that: The number of azimuth units and the number of elevation units of the array antenna are determined by the following process: According to the determined azimuth unit spacing and azimuth beam width requirements, the number of azimuth units of the array antenna N is s satisfy where λ max Indicates the maximum operating wavelength, θ 3dB Indicates the 3dB beamwidth in azimuth; According to the determined pitch unit spacing and pitch beam width requirements, the number of pitch units of the array antenna M is s satisfy Indicates the 3dB beamwidth in elevation.

6. The transmitting and receiving bi-located continuous wave phased array radar system according to claim 5, characterized in that: The wave position arrangement in the sinusoidal space coordinate system uses staggered beam arrangement, with 3dB beam width intervals in azimuth and 2.2dB beam width intervals in elevation. The coordinates of the arranged wave position in the sinusoidal space coordinate system (α ij ,β ij ), where αij represents the sinusoidal spatial abscissa of the j-th wave position in the i-th row, and βij represents the sinusoidal spatial ordinate of the j-th wave position in the i-th row; Phased array radar beam pointing in spherical coordinate system for: where θ ij represents the azimuth pointing direction of the jth beam in the i-th row in the spherical coordinate system of the phased array radar, represents the pitch pointing direction of the jth beam in the i-th row; Phased array radar beam pointing in space coordinate system (az ij ,el ij )for: Among them az ij Indicates the azimuth pointing direction of the jth beam in the i-th row in the phased array radar space coordinate system, el ij Indicates the pitch pointing direction of the jth beam in the i-th row.

7. The transmitting and receiving bi-located continuous wave phased array radar system according to claim 6, characterized in that: The transmit beam and receive beam are formed by controlling the amplitude and phase of the array antenna units according to the beam distribution in the spherical coordinate system of the phased array radar, wherein: The phase control of the transmitting array antenna unit is: in, n=0,1,…,N s -1 indicates the nth row of antenna elements, N s Indicates the number of antenna units in azimuth, m=0,1,…,M s -1 indicates the mth column antenna unit, M s Indicates the number of antenna units in elevation direction; The phase control of the receiving array antenna unit is: in, θ T Indicates the optimal array inclination angle.

8. A beam control method for a continuous wave phased array radar system with bi-directional transmission and reception, characterized in that: The system's array antenna structure layout uses a four-array structure layout. Each array covers a 90° range, and the transmitting and receiving arrays are separated. The transmitting array and the receiving array are alternately set at 45° intervals. The beam control method steps are as follows: Step 1: Determine the array azimuth scanning range in the phased array radar spatial coordinate system according to the array antenna structure layout; Step 2: Determine the optimal array tilt angle and array antenna geometry according to the elevation scanning range in the phased array radar spatial coordinate system; Step 3: Determine the sinusoidal spatial scanning area of the phased array radar and the azimuth unit spacing and elevation unit spacing of the array antenna based on the optimal array tilt angle determined in step 2 and the azimuth scanning range and elevation scanning range in the phased array radar spatial coordinate system; Step 4: Determine the number of azimuth and elevation elements of the array antenna according to the azimuth element spacing and elevation element spacing of the array antenna and the requirements for azimuth beamwidth and elevation beamwidth determined in step 3; Step 5: Determine the wave position arrangement in the sinusoidal space coordinate system according to the sinusoidal space scanning area of the phased array radar determined in step 3; Step 6: Determine the beam distribution in the phased array radar spherical coordinate system according to the arranged wave position determined in the phased array radar sinusoidal space coordinate system in step 5; Step 7: Based on the beam distribution in the spherical coordinate system of the phased array radar in step 6, the amplitude and phase of the array antenna unit are controlled to form the transmit beam and the receive beam.

9. The beam control method of the bi-directional continuous wave phased array radar system according to claim 8, characterized in that: In step 5, the beam arrangement method uses staggered beams, with 3dB beam width intervals in azimuth and 2.2dB beam width intervals in elevation. The coordinates of the arranged beam positions in the sinusoidal space coordinate system (α ij ,β ij ), where αij represents the sinusoidal spatial coordinate of the j-th wave position in the i-th row, β ij Represents the sinusoidal space ordinate of the j-th wave position in the i-th row.

10. The beam control method of the bi-directional continuous wave phased array radar system according to claim 9, characterized in that: The step 7 is specifically as follows: (7.1) The amplitude and phase of the transmit array antenna unit are controlled to complete transmit beam synthesis in space and form a transmit beam. The phase control formula of the transmit array antenna unit is as follows: in, n=0,1,…,N s -1 indicates the nth row of antenna elements, N s Indicates the number of antenna units in azimuth, m=0,1,…,M s -1 indicates the mth column antenna unit, M s Indicates the number of antenna units in elevation direction; d x Denotes the spacing between array antenna elements in azimuth, d y represents the pitch element spacing of the array antenna, θ ij represents the azimuth pointing direction of the jth beam in the i-th row in the spherical coordinate system of the phased array radar, represents the pitch pointing direction of the jth beam in the i-th row, α ij represents the sinusoidal spatial coordinate of the jth wave position in the i-th row, β ij represents the sinusoidal spatial ordinate of the j-th wave position in the i-th row; (7.2) The amplitude and phase of the receiving array antenna unit are controlled to form a receiving beam at the receiving end of the array antenna. The phase control formula of the receiving array antenna unit is as follows: in, az ij Indicates the azimuth pointing direction of the jth beam in the i-th row in the phased array radar space coordinate system, el ij represents the pitch pointing direction of the jth beam in the i-th row, θ T Indicates the optimal array inclination angle.

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