×

Three dimensional interferometric synthetic aperture radar terrain mapping employing altitude measurement and second order correction

  • US 5,189,424 A
  • Filed: 09/19/1991
  • Issued: 02/23/1993
  • Est. Priority Date: 09/19/1991
  • Status: Expired due to Term
First Claim
Patent Images

1. A method of terrain mapping employing a platform including first and second antennas, the first and second antennas each having a predetermined field of view and together forming an interferometer baseline, said method comprising the steps of:

  • moving the platform substantially perpendicular to the interferometer baseline along a set of substantially parallel platform paths;

    for each such platform path;

    repeatedly detecting the position of the moving platform,repeatedly detecting the distance above the terrain of the moving platform via a radiant ranging sensor,repeatedly transmitting a radar signal via at least one of the first and second antennas,receiving reflections of each of said transmitted radar signals via the predetermined field of view of at least one of the first and second antennas,forming first synthetic aperture complex image data for a plurality of resolution cells in slant range and Doppler frequency from radar reflections received by the first antenna employing plural transmitted radiant signals;

    forming second synthetic aperture complex image data for a plurality of resolution cells in slant range and Doppler frequency from radar reflections received by the second antenna employing plural transmitted radiant signals;

    determining the phase difference between said first and second synthetic aperture complex image data for each resolution cell;

    computing the elevation and ground range for each resolution cell within a selected one of said first and second synthetic aperture complex image data for each of said set of platform paths employing the detected position of the moving platform and the phase difference between said first and second synthetic aperture complex image data for that platform path;

    computing a first order corrected elevation and ground range for each resolution cell for each of said set of platform paths corrected for interferometer baseline roll angle employing said detected distance above the terrain of the moving platform of a corresponding adjacent platform path where the moving platform passed above the terrain imaged in said selected one of said first and second synthetic aperture complex image data; and

    computing a second order corrected elevation and ground range for each resolution cell corrected for the first return point of said radiant ranging sensor, employing said first order corrected elevation and ground range for resolution cells near each of said corresponding adjacent platform paths.

View all claims
  • 6 Assignments
Timeline View
Assignment View
    ×
    ×