Range migration image formation algorithm for stepped FM waveform
Single-Look Complex Image from Unfocused SFM SAR Data
Load a file that contains simulated unfocused synthetic aperture radar (SAR) data obtained with a stepped frequency modulated waveform. The waveform has a sample rate of 200 MHz, a pulse width of 250 nanoseconds, a pulse repetition frequency of 2/3 MHz, a frequency step size of 200 kHz, and 128 frequency steps.
data = load('RangeMigrationSFMExampleData.mat'); raw = data.raw; wvf = phased.SteppedFMWaveform(SampleRate=200e6, ... PulseWidth=250e-9,PRF=2e6/3,FrequencyStep=200e3,NumSteps=128);
The system works at an operating frequency of 4 GHz. The platform moves at a velocity of 400 meters per second and the distance between the beam center on the ground and the radar is 60 meters.
fc = 4e9; v = 400; rc = 60;
Generate a single-look complex image from the data. Plot the image.
slcimg = rangeMigrationSFM(raw,wvf,fc,v,rc); imagesc(abs(slcimg)) 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 frequency steps. The columns of
raw correspond to the bursts.
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.
 Cumming, Ian G., and Frank Hay-chee Wong. Digital Processing of Synthetic Aperture Radar Data: Algorithms and Implementation. Artech House Remote Sensing Library. Boston: Artech House, 2005.
 Tolman, Matthew A. "A Detailed Look at the Omega-k Algorithm for Processing Synthetic Aperture Radar Data.". MS thesis, Brigham Young University, 2008.
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)