Backscatter Pedestrian

Backscatter signals from pedestrian

Since R2021a

• 

Libraries:
Radar Toolbox

Description

The Backscatter Pedestrian block models the monostatic reflection of non-polarized electromagnetic signals from a walking pedestrian. The pedestrian walking model coordinates the motion of 16 body segments to simulate natural motion. The model also simulates the radar reflectivity of each body segment. From this model, you can obtain the position and velocity of each segment and the total backscattered radiation as the body moves.

Ports

Input

X — Incident radar signals

complex-valued M-by-16 matrix

Incident radar signals on each body segment, specified as a complex-valued M-by-16 matrix. M is the number of samples in the signal. See Body Segment Indices for the column representing the incident signal at each body segment.

The size of the first dimension of the input matrix can vary to simulate a changing signal length. A size change can occur, for example, in the case of a pulse waveform with variable pulse repetition frequency.

Data Types: double
Complex Number Support: Yes

Ang — Incident signal directions

real-valued 2-by-16 matrix

Incident signal directions on the body segments, specified as a real-valued 2-by-16 matrix. Each column of ANG specifies the incident direction of the signal to the corresponding body part. Each column takes the form of an [AzimuthAngle;ElevationAngle] pair. Units are in degrees. See Body Segment Indices for the column representing the incident direction at each body segment.

Data Types: double

AngH — Pedestrian heading

scalar

Heading of the pedestrian, specified as a scalar. Heading is measured in the xy-plane from the x-axis towards the y-axis. Units are in degrees.

Example: -34

Data Types: double

Output

Y — Combined reflected radar signals

complex-valued M-by-1 column vector

Combined reflected radar signals, returned as a complex-valued M-by-1 column vector. M equals the same number of samples as in the input signal, X.

Data Types: double
Complex Number Support: Yes

Pos — Positions of body segments

real-valued 3-by-16 matrix

Positions of body segments, returned as a real-valued 3-by-16 matrix. Each column represents the Cartesian position, [x;y;z], of one of 16 body segments. Units are in meters. See Body Segment Indices for the column representing the position of each body segment.

Data Types: double

Vel — Velocity of body segments

real-valued 3-by-16 matrix

Velocity of body segments, returned as a real-valued 3-by-16 matrix. Each column represents the Cartesian velocity, [vx;vy;vz], of one of 16 body segments. Units are in meters per second. See Body Segment Indices for the column representing the velocity of each body segment.

Data Types: double

Ax — Orientation of body segments

real-valued 3-by-3-by-16 array

Orientation axes of body segments, returned as a real-valued 3-by-3-by-16 array. Each page represents the 3-by-3 orientation axes of one of 16 body segments. Units are dimensionless. See Body Segment Indices for the page representing the orientation of each body segment.

Data Types: double

Parameters

Height (m) — Height of pedestrian

1.65 (default) | positive scalar

Height of pedestrian, specified as a positive scalar. Units are in meters.

Data Types: double

Walking Speed (m/s) — Walking speed of pedestrian

1.4 times pedestrian height (default) | nonnegative scalar

Walking speed of the pedestrian, specified as a nonnegative scalar. The motion model limits the walking speed to 1.4 times the pedestrian height set in the Height (m) parameter. Units are in meters per second.

Data Types: double

Propagation speed (m/s) — Signal propagation speed

physconst('LightSpeed') (default) | positive scalar

Signal propagation speed, specified as a real-valued positive scalar. The default value of the speed of light is the value returned by physconst('LightSpeed').

Data Types: double

Operating Frequency (Hz) — Carrier frequency

300e6 (default) | positive scalar

Carrier frequency of narrowband incident signals, specified as a positive scalar. Units are in Hz.

Example: 1e9

Data Types: double

Initial Position (m) — Initial position of pedestrian

[0;0;0] (default) | 3-by-1 real-valued vector

Initial position of the pedestrian, specified as a 3-by-1 real-valued vector in the form of [x;y;z]. Units are in meters.

Data Types: double

Initial Heading (deg) — Initial heading of pedestrian

0 (default) | scalar

Initial heading of the pedestrian, specified as a scalar. Heading is measured in the xy-plane from the x-axis towards y-axis. Units are in degrees.

Data Types: double

Simulate using — Block simulation method

Interpreted Execution (default) | Code Generation

Block simulation, specified as Interpreted Execution or Code Generation. If you want your block to use the MATLAB^® interpreter, choose Interpreted Execution. If you want your block to run as compiled code, choose Code Generation. Compiled code requires time to compile but usually runs faster.

Interpreted execution is useful when you are developing and tuning a model. The block runs the underlying System object™ in MATLAB. You can change and execute your model quickly. When you are satisfied with your results, you can then run the block using Code Generation. Long simulations run faster than in interpreted execution. You can run repeated executions without recompiling, but if you change any block parameters, then the block automatically recompiles before execution.

This table shows how the Simulate using parameter affects the overall simulation behavior.

When the Simulink^® model is in Accelerator mode, the block mode specified using Simulate using overrides the simulation mode.

Acceleration Modes

Block Simulation	Simulation Behavior
	Normal	Accelerator	Rapid Accelerator
Interpreted Execution	The block executes using the MATLAB interpreter.	The block executes using the MATLAB interpreter.	Creates a standalone executable from the model.
Code Generation	The block is compiled.	All blocks in the model are compiled.

For more information, see Choosing a Simulation Mode (Simulink).

More About

Body Segment Indices

Body segment indices define which columns in the X, Ang, BPPOS, and BPVEL ports contain the data for a specific body segment. Body segment indices define which page in the Ax port contains the data for a specific body segments. For example, column 3 of X contains sample data for the left lower leg. Column 3 of Ang contains the arrival angle of the signal at the left lower leg.

Body Segment	Index
Left foot	1
Right foot	2
Left lower leg	3
Right lower leg	4
Left upper leg	5
Right upper leg	6
Left hip	7
Right hip	8
Left lower arm	9
Right lower arm	10
Left upper arm	11
Right upper arm	12
Left shoulder	13
Right shoulder	14
Head	15
Torso	16

Extended Capabilities

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

Version History

Introduced in R2021a