Range Doppler image formation algorithm for linear FM waveform
returns a single-look complex image
slcimg = rangeDopplerImagerLFM(
slcimg generated from raw synthetic
aperture radar (SAR) data obtained using a linear frequency modulated (LFM) pulse
fc specifies the operating frequency.
v specifies the platform speed.
rc is the
radar-to-beam center distance.
Generate Image for Unfocused SAR
Generate a complex-valued single-look SAR image from simulated unfocused raw data. The radar transmits an LFM waveform. The LFM waveform has a 3 microsec duration with a PRF of 960 Hz. The radar has an operating frequency of 9 GHZ with a pulse sweep bandwidth of 29.979 MHz. The radar platform moves at 100 m/s. The radar-to-beamcenter distance is 1.118 km.
FIrst, load the raw image data from a mat-file. The raw data consists of a 481-by-577 complex-valued matrix. Then compute the focused SAR image.
load('RangeMigrationLFMExampleData.mat') slcimg = rangeDopplerImagerLFM(raw,waveform,fc,v,rc); imagesc(abs(slcimg)) title('SLC Image') xlabel('Cross-Range Samples') ylabel('Range Samples')
raw — Unfocused IQ raw SAR data
M-by-N complex-valued matrix
Unfocused IQ raw SAR data, specified as an
M-by-N complex-valued matrix. The data is the
unfocused in-phase and quadrature (I/Q) raw data collected by the SAR system. Rows of
raw correspond to 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
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.
v — Platform velocity
Platform velocity, specified as a positive scalar. Units are in meters per second.
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.
 Curlander, John C., Robert N. McDonough. Synthetic Aperture Radar: Systems and Signal Processing. Wiley, 1991.
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)