Patents by Inventor Daniel N. Held

Daniel N. Held has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 7420504
    Abstract: A method of operating a multibeam radar carried on a platform flying a mission over a prescribed flight path to obtain images of a plurality of target areas, the beams of said radar being the result of respective transmit pulses and beam returns being received by respective receive windows. A range of pulse repetition frequencies and pulse repetition frequency change rates are used in an iterative process to determine non-collision alignments of any combination of transmit pulses and receive windows. When a non-collision alignment is determined the particular arrangement producing that non-collision alignment is used in a simulated flight of the platform to determine dwell time before a collision occurs. An arrangement that produces sufficient dwell time to accomplish a mission is then used in an actual flight of the platform.
    Type: Grant
    Filed: January 6, 2006
    Date of Patent: September 2, 2008
    Assignee: Northrop Grumman Corporation
    Inventors: Daniel N. Held, Elbert L. Cole, Jr., Martin J. Decker, Charles Y. Chen
  • Patent number: 5818383
    Abstract: An interferometric moving target radar imaging system includes a plurality of simultaneously operating apertures, receivers and processing channels which together coherently process RF return signals to image a moving vehicle. The system corrects for the different phase centers of the apertures and interferometrically combines the return signals from different apertures to attenuate the energy from stationary objects. The true azimuth location of the moving vehicle within main beam clutter spread is then determined which facilitates distinguishing between slow moving and stationary objects to detect the moving objects which are then tracked and imaged in the range doppler domain.
    Type: Grant
    Filed: October 28, 1994
    Date of Patent: October 6, 1998
    Assignee: Northrop Grumman Corporation
    Inventors: Edward F. Stockburger, Hugh D. Holt, Jr., Daniel N. Held, Robert A. Guarino
  • Patent number: 4829303
    Abstract: Two alternative methods are disclosed for digital reduction of synthetic aperture multipolarized radar data using scattering matrices, or using Stokes matrices, of four consecutive along-track pixels to produce "averaged" data for generating a synthetic polarization image.
    Type: Grant
    Filed: May 18, 1988
    Date of Patent: May 9, 1989
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventors: Howard A. Zebker, Daniel N. Held, Jakob J. van Zul, Pascale C. Dubois, Lynne Norikane
  • Patent number: 4450447
    Abstract: A synthetic aperture radar (SAR) target simulator for simulating the radar return, or echo, from a target seen by a SAR antenna mounted on a platform moving with respect to the target includes a first-in first-out memory (26) which has digital information clocked in at a rate related to the frequency of a transmitted radar signal and digital information clocked out with a fixed delay defining range between the SAR and the simulated target, and at a rate related to the frequency of the return signal. An rf input signal having a frequency similar to that utilized by a synthetic aperture array radar is mixed with a local oscillator (16) signal to provide a first baseband signal having a frequency considerably lower than that of the rf input signal. The first baseband signal is converted to a plurality of digital words which are clocked into the memory (26) at a rate related to the frequency of the local oscillator (16).
    Type: Grant
    Filed: July 17, 1981
    Date of Patent: May 22, 1984
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventors: Howard A. Zebker, Daniel N. Held, Richard M. Goldstein, Thomas C. Bickler