Range migration image formation algorithm for frequency-modulated CW waveform
Single-Look Complex Image from Unfocused FMCW Data
Load a file that contains simulated unfocused synthetic aperture radar (SAR) data obtained with a frequency modulated continuous wave waveform sampled at 15 MHz. The waveform has a sweep time of 25 microseconds, a sweep bandwidth of 20 MHz, and sweeps in the
data = load("RangeMigrationFMCWExampleData"); raw = data.raw; wvf = phased.FMCWWaveform(SampleRate=15e6, ... SweepTime=2.5e-5,SweepBandwidth=20e6,SweepDirection="Down");
The system works at an operating frequency of 3 GHz. The platform moves at a velocity of 200 meters per second and the distance between the beam center on the ground and the radar is 46.672 meters.
fc = 3e9; v = 200; rc = 46.672;
Generate a single-look complex image from the data. Plot the image and zoom in on the first 20 along-range samples.
slcimg = rangeMigrationFMCW(raw,wvf,fc,v,rc); imagesc(abs(slcimg(1:20,:))) xlabel("Cross-Range Samples") ylabel("Range Samples")
raw — Raw SAR data
Raw SAR data, specified as a matrix. The data is the unfocused in-phase and
quadrature (I/Q) raw data collected by the SAR system. The rows of
raw correspond to the along-range samples. The columns of
raw correspond to the pulses received as the platform moves along
the cross-range direction.
raw must have at least two rows.
waveform — Input waveform
Input waveform, specified as a
v — Platform velocity
Platform velocity, specified as a positive scalar. Units are in meters per second.
fc — Operating frequency
Operating frequency, specified as a positive scalar. Units are in Hz.
2.8e9 Hz specifies a typical S-band operating-frequency value for
airport and weather radar systems.
rc — Distance between radar and beam center
Distance between radar and beam center on the ground, specified as a positive scalar. Units are in meters.
Specify optional pairs of arguments as
the argument name and
Value is the corresponding value.
Name-value arguments must appear after other arguments, but the order of the
pairs does not matter.
SquintAngle — Squint angle
0 (default) | scalar in the range
Squint angle of the antenna from the broadside direction in degrees, specified as a scalar in the range
PropagationSpeed — Signal propagation speed
physconst("LightSpeed") (default) | positive scalar
Signal propagation speed in meters per second, specified as a positive scalar.
343 meters per second approximates the speed of sound at sea level and at a temperature of 20 °C under normal atmospheric conditions.
C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.
Introduced in R2022a
- Stripmap Synthetic Aperture Radar (SAR) Image Formation (Radar Toolbox)
- Squinted Spotlight Synthetic Aperture Radar (SAR) Image Formation (Radar Toolbox)
- Synthetic Aperture Radar System Simulation and Image formation (Radar Toolbox)