ctrectcorners

Corner measurements of constant turn-rate rectangular target

Syntax

zCorners = ctrectcorners(states)

zCorners = ctrectcorners(states,sensorParameters)

Description

zCorners = ctrectcorners(states) returns the positions of the corners for constant turn-rate rectangular targets in a rectangular frame.

zCorners = ctrectcorners(states,sensorParameters) specifies the parameters of the sensor that measures the corners of rectangular targets.

Examples

Position of Corners in Sensor Reference Frame

Define sensor reference frame by specifying the sensorParameters input.

sensorPosition = [-5;10;0];
sensorOrientation = rotmat(quaternion([30 0 0],'eulerd','ZYX','frame'),'frame');
sensorParams = struct('Frame','Rectangular', ...
    'OriginPosition',sensorPosition,...
    'Orientation',sensorOrientation);

Define the constant turn-rate state for the rectangle target.

state = [10;5;1.6;30;0.5;4.7;1.8];

Compute corner positions in sensor reference frame.

corners = ctrectcorners(state,sensorParams);

Set up visualization environment using theaterPlot.

% Create a theater plot.
tp = theaterPlot;
% Plot the state using a track plotter.
statePlotter = trackPlotter(tp,'DisplayName','Target State');
% Plot the corners using a detection plotter.
cornerPlotter = detectionPlotter(tp,'DisplayName','Corners');

Compute inputs and plot.

targetPos = [state(1) state(2) 0];
targetOrientation = rotmat(quaternion([state(4) 0 0],'eulerd','ZYX','frame'),'frame');
targetDims = struct('Length',state(6),...
    'Width',state(7),...
    'Height',5,...
    'OriginOffset',[0 0 0]);

cornerPosGlobal = sensorOrientation*corners(:,:) + sensorPosition;
statePlotter.plotTrack(targetPos,targetDims,targetOrientation);
cornerPlotter.plotDetection(cornerPosGlobal');

Input Arguments

states — Current rectangular target states

7-by-N real-valued matrix

Current rectangular target states, specified as a 7-by-N real-valued matrix, where N is the number of states. The seven dimensional rectangular state is defined as [x; y; s; θ; ω; L; W]. The meaning of these variables and their units are:

Variable	Meaning	Unit
x	Position of the rectangle center in x direction	m
y	Position of the rectangle center in y direction	m
s	Speed in the heading direction	m/s
θ	Orientation angle of the rectangle with respect to x direction	degree
ω	Turn-rate	degree/s
L	Length of the rectangle	m
W	Width of the rectangle	m

Example: [1;2;2;30;1;4.7;1.8]

Data Types: single | double

sensorParameters — Parameters for sensor transform function

structure | array of structures

Parameters for the sensor transform function, returned as a structure or an array of structures. If you only need to transform the state once, specify it as a structure. If you need to transform the state n times, specify it as an n-by-1 array of structures. For example, to transform a state from the scenario frame to the sensor frame, you usually need to first transform the state from the scenario rectangular frame to the platform rectangular frame, and then transform the state from the platform rectangular frame to the sensor spherical frame.

The fields of the structure are:

Field	Description
Frame	Child coordinate frame type, specified as 'Rectangular' or 'Spherical'.
OriginPosition	Child frame origin position expressed in the parent frame, specified as a 3-by-1 vector.
OriginVelocity	Child frame origin velocity expressed in the parent frame, specified as a 3-by-1 vector.
Orientation	Relative orientation between frames, specified as a 3-by-3 rotation matrix. If the IsParentToChild property is set to false, then specify Orientation as the rotation from the child frame to the parent frame. If the IsParentToChild property is set to true, then specify Orientation as the rotation from the parent frame to the child frame.
IsParentToChild	Flag to indicate the direction of rotation between parent and child frame, specified as true or false. The default is false. See description of the Orientation field for details.
HasAzimuth	Indicates whether outputs contain azimuth components, specified as true or false.
HasElevation	Indicates whether outputs contain elevation components, specified as true or false.
HasRange	Indicates whether outputs contain range components, specified as true or false.
HasVelocity	Indicates whether outputs contain velocity components, specified as true or false.

Note that here the scenario frame is the parent frame of the platform frame, and the platform frame is the parent frame of the sensor frame.

When frame is 'Rectangular', HasVelocity determines if the measurement is returned in the form of [x; y; z; v_x; v_y; v_z] or [x; y; z].

When frame is 'spherical', the returned measurements are in the order of [azimuth, elevation, range, range-rate]. The elements of the returned measurements are determined by:

• HasAzimuth — Determines if output contains azimuth measurement.

• HasElevation — Determines if output contains elevation measurement.

• HasRange — Determines if output contains range measurement.

• HasVelocity — Determines if output contains range-rate measurement on the condition that HasRange is 'true'. If HasRange is 'false', the returned measurement does not contain range-rate (even though HasVelocity is 'true').

Data Types: struct

Output Arguments

zCorners — States of corners

real-valued M-by-N-by-4 array.

States of corners, returned as a real-valued M-by-N-by-4 array. Each page (an M-by-N matrix) of the array corresponds to one corner for all the states given in the states input. N is the number of states. M is the dimension of output specified by the sensorParameters input. If unspecified, the default value of M is three, which corresponds to 3-D Cartesian position coordinates.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.

Version History

Introduced in R2018b