Backscatter signals from pedestrian
Phased Array System Toolbox / Environment and Target
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.
X— Incident radar signals
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.
Complex Number Support: Yes
Ang— Incident signal directions
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
[AzimuthAngle;ElevationAngle] pair. Units are in degrees. See
Body Segment Indices for the column
representing the incident direction at each body segment.
AngH— Pedestrian heading
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.
Y— Combined reflected radar signals
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,
Complex Number Support: Yes
Pos— Positions of body segments
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.
Vel— Velocity of body segments
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.
Ax— Orientation of body segments
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.
Height (m)— Height of pedestrian
1.65(default) | positive scalar
Height of pedestrian, specified as a positive scalar. Units are in meters.
Walking Speed (m/s)— Walking speed of pedestrian
1.4times 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.
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
Operating Frequency (Hz)— Carrier frequency
300e6(default) | positive scalar
Carrier frequency of narrowband incident signals, specified as a positive scalar. Units are in Hz.
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
[x;y;z]. Units are in meters.
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.
Simulate using— Block simulation method
Interpreted Execution(default) |
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
Generation. Compiled code requires time to compile but usually runs
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
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.
|Block Simulation||Simulation Behavior|
|The block executes using the MATLAB interpreter.||The block executes using the MATLAB interpreter.||Creates a standalone executable from the model.|
|The block is compiled.||All blocks in the model are compiled.|
For more information, see Choosing a Simulation Mode (Simulink).
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 Indices
|Body segment||Body segment index|
|left lower leg||3|
|right lower leg||4|
|left upper leg||5|
|right upper leg||6|
|left lower arm||9|
|right lower arm||10|
|left upper arm||11|
|right upper arm||12|