1. Add radar to aircraft
First open MATLAB , run the following MATLAB script to add scenes and aircraft:
%打开一个STK应用实例
uiapp = actxserver('STK10.application');
%获取STK用户界面
root = uiapp.Personality2;
%显示界面
uiapp.visible = 1;
%创建一个新场景并设定时区
root.NewScenario('open_STK');
%设置时间日期格式为UTCG
root.UnitPreferences.Item('DateFormat').SetCurrentUnit('EpSec');
root.UnitPreferences.Item('Distance').SetCurrentUnit('m');
aircraft = root.CurrentScenario.Children.New('eAircraft', 'MyAircraft');
aircraft.VO.Model.ModelData.set('Filename',
'STKData\VO\Models\Air\b-52_stratofortress.mdl');
route = aircraft.Route;
ptsArray = {37.5378,101,5000,20,5;
47.2602,30.5517,5000,20,5;
47.2602,30.5517,5000,20,5;
39.5378,14.2207,5000,20,5;};
route.SetPointsSmoothRateAndPropagate(ptsArray);
%Propagate the route
route.Propagate; Then add radar:
aircraft.Children.New('eRadar','Radar1');2. Introduction to Radar
2.1 Classification by beam type
(1) Pulse Radar ( Pulse Radar ): Ranging.
(2) Doppler radar ( PD )/moving target indicator ( MTI ): to detect the speed and orientation of moving objects.
(3) Continuous wave radar ( CW ): Doppler frequency shift or velocity detection.
(4) LiDAR ( LIDAR ): Narrow laser beam.
2.2 Classification by Transmitter and Receiver
(1) Monostatic Radar (Monostatic) : A single antenna is used for transmission and reception.
(2) Bistatic Radar (Bistatic) : Separate antennas are used for transmission and reception.
2.3 Key concepts
(1) Pulse repetition frequency (PRF): The number of pulses transmitted per second, which is the reciprocal of the pulse repetition interval ( PRI). The pulse repetition interval is the time interval between one pulse and the next. 1/2 of the pulse repetition frequency is called the Nyquist frequency limit. If the Doppler frequency shift value exceeds this limit, the frequency change detected by the pulse Doppler will have an artifact of magnitude and direction, which is called Frequency distortion .
(2) Radar Cross Section (RCS) : The RCS of a target is equal to the ratio of the power reflected by the unit solid angle target in the direction of the radar receiving antenna (per single solid angle) to the power density incident on the target (per square meter).
(3) Synthetic Aperture Radar (SAR) : Synthetic Aperture Radar uses a small-aperture antenna that moves relative to the target to coherently process the echoes received at different positions to obtain a higher-resolution imaging radar.
3. Key Radar Settings
Notice
STK radar has no independent subclasses and public methods, so radar properties cannot be set in MATLAB , and can only be set directly in the STK interface.
3.1 Select Radar Type
There are two types of radar in STK : Monostatic and Bistatic :
3.2 Mode selection
There are two modes: Synthetic Aperture ( SAR) and Search Track ( Search Track ), and the default is Search Track.
3.3 Waveform parameter setting
The waveform has fixed pulse wave ( Fixed PRF ) and continuous wave ( Continuous Wave ), and the default is fixed pulse wave. For fixed pulse waves, there are two key parameters that need to be set:
(1) PRF : determines the number of pulses emitted per second.
(2) Pulse width (Pulse width)
For continuous wave, the analysis mode is generally set, including:
(1) Fixed time interval (2) Global SNR . Two analysis modes.
3.4 Radar 3D graphics display settings
Check Show Volume under Volume Graphics , the radar beam cone will be displayed:
Then check show as wireframe , and the wireframe will be displayed:
Slide the sliders below to adjust the density and coverage of the rays in the wireframe. resolution is the resolution, which controls the interval between rays, Point is the number of equal points, start and stop are the starting and ending angles respectively.
For example, set the radar scanning azimuth range to [-30°,30°] :
3.5 Antenna Setup
STK opens the radar property window, and selects the antenna ( Antenna ) tab to view the antenna type. STK uses a parabolic antenna by default.
Different antenna types can produce different beam shapes, resulting in different detection distances and field of view angles. Several commonly used types are listed below:
(1) Parabolic antenna (parabolic)
(2) Helix antenna (helix)
(3) dipole antenna (dipole)
(4) Gaussian antenna
3.6 Radar pointing and position on the fuselage
The default orientation of the airborne radar is the Z axis of the aircraft system (British coordinate system) . To adjust the detection direction of the radar, you can adjust the azimuth and elevation angle of the antenna in the radar property window Basic>Antenna>orientation , for example, the previous The center of the airborne radar beam is adjusted to the x- axis of the aircraft system (British coordinate system) , that is, the elevation angle is set to 0, so that ground detection can be changed to air detection.
It is found that the radar wave covers a part of the nose, which is not beautiful. You can set the origin of the radar to shift a little towards the nose:
