meeting11_18_98.html

Some Notes from the Lockheed-Martin/Univ. of Illinois Meeting on
Nov. 11, 1998

By Aaron Lanterman

Notes from the Morning Meeting

The morning meeting focused on the experiences of workers at Lockheed-Martin.

  • Some researchers at Lockheed-Martin have employed the NEC software
    (developed by Lawrence Livermore) for
    scattering calculations and the AREPS model (contact: Wayne Paterson,
    619-553-1423, www.spawar.navy.mil) for atmospheric propagation
    calculations.

  • The L-M system target track update rate is 8 updates per second.
  • Useful book: “Bistatic Radar” by Nicholas J. Willis, available from
    Technology Service Corp., 962 Wayne Ave., Silver Spring, MD 20910.

  • For television transmissions, the L-M system makes no attempt to
    monitor the direct signal from the transmitter, since most of the power
    is in the carrier anyway. For FM transmissions, the L-M system does measure
    the direct path signal and correlates it with the
    signal which bounces off the target.

  • The polarization characteristics of the transmitted signal vary from
    station to station. For FM signals, there is some emphasis on vertically
    polarized signals, since most car antennas are vertical.

  • It would be useful to collect data from the L-M system while using an
    optical camera to visually track and identify aircraft in order to get
    “ground truth.” It might be especially helpful to conduct such experiments
    at a small, low-activity airport, in order to cut down on background clutter
    and generally make the data easier to analyze.

  • Some experiments on detecting and tracking a car going in circles
    in a parking lot showed that the background clutter introduced by other
    moving objects in the scene can be a significant effect. Also, there were
    duplicate doppler signatures corresponding to other information in the TV
    signal. These duplicate signatures were 13 to 20 db down from the main
    signature.

  • The FCC has a database of information about radio and television
    transmitters in the U.S., including latitude, longitude, etc.

  • The LM system receives on four bands – VHF low (2-6), VHF high
    (7-13), UFH, and FM. Beamforming is performed digitally.

Notes from the Afternoon Meeting

The afternoon focused on potential areas of investigation and
collaboration.

  • Target identification/estimation
    • Basic detection
    • Different levels of classification
    • Position estimation (especially altitude)
    • Orientation estimation (linked to tracking)
    • Performance bounds
  • Target Imaging
    • Useful for targets which may not be in a classifier’s library
    • Linear methods
      • Dependence of reflectance on aspect angle
      • Use of multiple receiving antennas
      • Interferometry
      • Dependence on source bandwidth & locations
      • Autofocus (phase alignment issues)
    • Nonlinear methods
  • Areas applicable to both ID and imaging
    • Principles of multistatic radar systems
    • Use of polarization information
    • Collection of experimental data
    • Simulated data: XPATCH, FISC, etc.
    • Comparison of simulated and real data
    • Techniques based on electromagnetic models
    • System design (Ex: best place to put sensors)
    • Role of tracking: motion dynamics, track association