GTRI Overview

GTRI 3D Turntable Data Description:

The GTRI turntable data consists of multi-polarization, X-band (9.6 GHz center frequency) radar phase history data. Although the original data supported higher range and cross range resolutions, the data has been down-sampled in frequency and azimuth to a range and cross range resolution of 1 foot x 1 foot, after applying a Taylor window with -35 dB sidelobes and a pre-windowed vertical resolution of 1 foot. Each file contains sufficient bandwidth and aperture to support the indicated range and cross range resolutions and corresponds to a specific transmit/receive polarization and nominal target aspect. Furthermore, each file contains an ASCII header defining, among other things, the radar center frequency, parent file name, target aspect, and sensor depression angle (see File Convention below). The data provides the capability to generate 3-D imagery. Target complex frequency response is provided as a function of both target azimuth and elevation. In order to develop a 3-D image with the indicated resolutions, all files for a given polarization and target aspect must be processed using an appropriate 3-D image formation algorithm. Aspect angle is implicitly defined by the last two digits of each file name, and polarization is defined by the last two letter in each file name.

The data nominal sampling rates were as follows:

  • Frequency : 3 MHz
  • Aspect : 0.05 Degrees
  • Elevation : 0.138 Degrees