Radar and Measurement Technology
Data Processing

SPC has a number of in-house data processing capabilities, developed using Matlab, Labview, and Fortran. (An overview of these capabilities can be downloaded here.)

GenGUI
GenGUI is a suite of MATLAB-based utilities designed to analyze and image MkV radar data. An overview of the GenGUI suite can be dowloaded here.

GenGUI1 is used to extract I/Q data, view header information, and obtain key parameters from the MkV data file format. The pre-processing in GenGUI1 is modular and can easily be adapted to other radar formats. Both GenGUI2 and GenGUI3 work on generic I/Q files.

GenGUI2 is intended to provide quick-look capability to determine the quality of collected data. Capabilities include:

  • Display amplitude, phase, real (I), or imaginary (Q) components of data
  • Allow selection of sub-bands of frequencies to process
  • Perform 1- and 2-dimensional FFTs
  • Apply windowing; arbitrary phase adjustment; calibration or background-correction; bias correction
  • View single frequency over burst, or single burst over frequency
  • View data on a dB scale with user-defined limits; maximum and minimum values in data to check for saturation
  • Export selected data as an ASCII file of either real and imaginary components or amplitude and phase
  • Save intermediate results as MATLAB variables for additional processing

GenGUI3 is used to image SAR data and reference to geographic location. Capabilities include:

  • Superimpose GPS data from measurements onto Digital Elevation Maps (DEM) or bitmaps
  • Interactively select region to image and provide immediate feedback as to availability of data
  • Allow viewing intermediate range profile data and region of data to be imaged
  • Perform time-domain tomographic imaging with user-defined interpolation
  • Incorporate DEM, calibration files, background files, position files, and bias files
  • Allow easy interactive manipulation of images; interactive definition of image coordinates
  • Work in metric or English units
  • Save results for subsequent processing
3D Imaging
Using SPC's rotator and linear rail, SAR/ISAR data were collected on a specially-designed target designed to be completely asymmetric. The data were processed using tomographic techniques to develop a 3D image. X-Y slices at varying heights are shown below.
Pulse-Doppler Processing
The data normally associated with instrumentation radar systems contain only a few range gates for each PRI. Instrumentation enhancements for the Ariane re-entry program provide continuous sampling in range. Where the MkV data represent samples at a given range, the ADDR system collects contiguous range-gate samples. Physical range is determined from the number of samples between the pulse (main bang) and the return of interest.

In order to interpret the data and extract desired information, a data processing system was developed in Labview. The software provides the following capabilities:

Data Reduction

  • Extract desired data set from raw data on ADDR system
  • Search raw data to find locations of main bangs
  • Analyze location of main bangs to identify waveform attributes
  • Extract byte addresses (for each interleaved waveform)and store for use in processing

Data Processing

  • Use byte addresses to identify desired data for processing
  • Apply iterative SNR optimization routine for bias rejection on pulse-to-pulse basis
  • Perform Doppler processing, remove zero Doppler, and sum Doppler bins
  • Apply matched filtering routine
  • Correlate a PRI to the date/time when it was collected
  • Automatically track peaks in Range-Amplitude trace
  • Create multiple plots (Range-Time-Intensity (RTI), Range-Doppler-Intensity (RDI), Doppler-Time-Intensity (DTI), Range-Amplitude)
  • Export plots in JPG/BMP formats
  • Export data in ASCII format