Patents by Inventor Toshihiko Hagisawa

Toshihiko Hagisawa 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: 4809002
    Abstract: A moving target indicator device comprising a first clutter removing circuit for responding to a radar having a variable transmit repetition time and for removing clutter having a Doppler speed of nearly zero from a radar received signal having stationary clutter and moving clutter. The device further includes a correction circuit to keep the amplitude components and the phase components of the first clutter removing circuit output substantially constant. A second clutter removing circuit removes clutter having a constant amplitude component and phase component from the output of the correction circuit.
    Type: Grant
    Filed: February 13, 1985
    Date of Patent: February 28, 1989
    Assignee: NEC Corporation
    Inventors: Fusaji Togashi, Toshihiko Hagisawa
  • Patent number: 4661816
    Abstract: An adaptive radar signal processor is operable to effectively suppress clutters and extract a target signal with a high degree of accuracy and includes a memory storing two-dimensional radar data corresponding to range and azimuthal directions, multipliers multiplying each of data of the same range but different azimuthal direction read out from the memory, an adder generating the added data of the multipliers as an estimated data, and a weighting coefficient determinater which determines the optimum weighting coefficients based upon the stored radar data so that the difference between the radar data and the estimated data at an observing position is minimized, and produces the difference data as a clutter-suppressed radar data.
    Type: Grant
    Filed: October 5, 1983
    Date of Patent: April 28, 1987
    Assignee: NEC Corporation
    Inventors: Toshimitsu Musha, Eichi Kiuchi, Toshihiko Hagisawa
  • Patent number: 4658255
    Abstract: An adaptive radar signal processing apparatus for a radar system wherein filter coefficients are switched for individual regions so that optimum filter characteristics can be obtained for the individual stationary clutter region, moving clutter region, clear region, etc. thereby providing suppression of undesired signals which is adapted for each region.
    Type: Grant
    Filed: July 23, 1984
    Date of Patent: April 14, 1987
    Assignee: NEC Corporation
    Inventors: Hiroshi Nakamura, Eiichi Kiuchi, Toshihiko Hagisawa