NVESD MMW RADAR: SIMULATED RANGE-PROFILES

Wright Laboratory has provided CIS with the High Resolution Radar signature prediction tool XPATCH. This simulator was used with CAD models of the T-62 tank and the HMMWV to produce a series of simulated millimeter-wave range-profiles for each of these vehicles. CIS has used these data to test algorithms for target recognition and orientation estimation under various models for the HRR data.

The Vehicles

CAD models for the HMMWV and the T-62 tank were obtained from public domain archives. These models were originally obtained in the "wavefront" or "OBJ" format, and were converted using locally developed software to the XPATCH-compatible "facet" format. Shown below are images captured from each of the vehicles in the original format.


The Data

The HRR simulator XPATCH was used to simulate range-profiles for each of the two vehicles. The frequency parameters for the simulation were chosen to correspond with actual millimeter-wave data supplied to CIS by the Night Vision Laboratory. The complex backscattered far-field is simulated at 64 discrete frequencies centered around 35 GHz and covering a bandwidth of 320 MHz. The wavelength at the carrier frequency is 8.57 mm and the range resolution is 46.9 cm. This center frequency actually corresponds to the technical definition of Ka-band, but the data are commonly referred to as millimeter-wave.

Range-profiles were simulated for each of the each of the vehicles at at azimuth angles uniformly sampled around the circle at 1 degree increments. The elevation angle was help constant at 1 degree for all of the simulations. XPATCH produces range profiles for each of the three independent linear polarization states: {vv, hv, hh}. These collections of range-profiles are depicted in a series of 48 images described below. They are also available for downloading in 6 binary files, also described below.

Images

The 360 range-profiles for each of the two vehicles and for each of the three polarization states are depicted in 48 images. Each image is a waterfall plot of the magnitude of the range-profiles for one of the vehicles, for one of the polarization states, and over a 45 degree sweep in azimuth angle. Click on any of the thumbnail images below to see a full-size version.

Inspection of these images reveals that in many cases, a single range-profile from the set of 45 has much larger magnitude than the others. This is due to the fact that both target models contain large flat surfaces on each side. As a result, when the azimuth angle is a multiple of 90 degrees, one of these surfaces is normal to the radar line-of-sight, producing a very large response in the hh and vv range-profiles.

HMMWV DATA

hh polarization hv polarization vv polarization

T-62 DATA

hh polarization hv polarization vv polarization

Binary Files

The range profiles depicted above are available for downloading. They are grouped by vehicle and polarization state into 6 binary files. The files are named hummer_rps_hh.dat, hummer_rps_hv.dat, hummer_rps_vv.dat, t62_rps_hh.dat, t62_rps_hv.dat, and t62_rps_vv.dat. All data in all of the files is stored as single-precision floating-point values. No header information is contained in any of the files. Each consecutive pair of floats gives the real and imaginary parts of the complex-valued return in a single range bin. Each consecutive set of 64 range bins (128 floats) gives the range-profile for a particular azimuth angle. The range-profiles are listed consecutively in the file, beginning with 0 degrees azimuth, and proceeding in 1 degree increments up to 359 degrees azimuth. Click on the links below to download the associated binary file. The links are currently disabled while we obtain approval to release the data.

HMMWV data: hh polarization
HMMWV data: hv polarization
HMMWV data: vv polarization

T-62 data: hh polarization
T-62 data: hv polarization
T-62 data: vv polarization

CIS (cis@cis.jhu. edu); page last updated on Wed Dec 13 10:10:54 2000.