Pulse-type Noise Elimination Or Compensation (e.g., Sky Waves) Patents (Class 342/421)
  • Patent number: 7750842
    Abstract: In one aspect, a system to generate a radar signature of an object includes electromagnetic processing modules that include a first module including at least one processing unit to perform a shooting and bouncing (SBR) technique to solve for physical optics and multi-bounce characteristics of the object, a second module including a processing unit to perform a physical theory (PTD) technique to solve for material edges of the object and a third module including a processing unit to perform an incremental length diffraction coefficient (ILDC) to solve for material boss/channel. Results from the first, second and third modules are coherently integrated by frequency to generate radar cross section (RCS) values of the object in real-time. Performance of the system is scalable by adding processing units to at least one of the first, second or third modules.
    Type: Grant
    Filed: September 18, 2008
    Date of Patent: July 6, 2010
    Assignee: Raytheon Company
    Inventors: Chul J. Lee, Axel R. Villanueva
  • Patent number: 7646333
    Abstract: An electronic circuit comprises a randomizing bit generator configured to generate a randomizing bit sequence based on a sequence selection input signal. The randomizing bit generator includes a counter operable to provide an individual starting count for the randomizing bit sequence and a parity generator responsive to an output of the counter. The circuit further comprises a pseudo-random number generator responsive to the randomizing bit generator. The pseudo-random number generator is operable to provide at least one pulsed signal based at least in part on the random bit sequence. The electronic circuit is operable to substantially eliminate interference in a series of pulsed signal transmissions comprising the at least one pulsed signal from each of two or more navigation devices, where each of the pulsed signals from each of the navigation devices is separated by an automatically adjustable time interval.
    Type: Grant
    Filed: June 4, 2008
    Date of Patent: January 12, 2010
    Assignee: Honeywell International Inc.
    Inventors: Mark S. Shoemaker, Peter Peterson, Curtis J. Petrich
  • Patent number: 6765532
    Abstract: A system is provided for assisting in the detection and tracking of narrowband signals arriving at an antenna array operating over a wide detection bandwidth and in a crowded RF environment. Since the nature of the detection mission is constrained to be a general search, the system does not attempt to detect signals of interest via matched filtering mechanisms (i.e. training sets), but exploits general properties such as power, frequency, time and angle of arrival. For the purposes of providing sufficient Frequency/Time resolution as well as to avoid array overloading in the detection process, the digitized wideband streaming data is frequency channelized using a sufficiently high revisit rate for the signal set of interest, constrained by the required feature detection accuracy or environment adaption rates. Within each frequency subchannel, efficient array signal subspace tracking techniques are used to separate and track spatially separated cochannel signals.
    Type: Grant
    Filed: December 17, 2002
    Date of Patent: July 20, 2004
    Assignee: Bae Systems Information and Electronic Systems Integration Inc.
    Inventors: Thomas R. Vaccaro, Norman D. Paul
  • Patent number: 4912479
    Abstract: There is disclosed a microwave landing system wherein there are provided at least two means which are spaced by a predetermined distance and from two of which beams radiate alternately to scan a predetermined region vertically and horizontally. In the microwave landing system, multipath propagating beams due to the scanning beams or side-lobes thereof are of out of phase or in non-correlation with each other in a receiving means in an aircraft to suppress multipath errors.
    Type: Grant
    Filed: April 21, 1989
    Date of Patent: March 27, 1990
    Assignee: NEC Corporation
    Inventors: Takashi Nishimura, Taksukichi Koshio
  • Patent number: 4665404
    Abstract: The system includes a method and apparatus for transmitting a spread spectrum signal from each of a plurality of base stations. The spread spectrum signal has a predetermined timing and has a ground wave component and a sky wave component. The signal is transmitted with a repetition time at least as great as a maximum anticipated delay time of the sky wave component such that the ground wave component of the transmitted spread spectrum signal can be distinguished from the sky wave component. The signal is detected at each of a plurality of mobile stations and the timing of the detected signal is compared to a local timing signal. The phase difference between these signals is indicative of the range of the base station from the mobile station.
    Type: Grant
    Filed: October 19, 1984
    Date of Patent: May 12, 1987
    Assignee: Offshore Navigation, Inc.
    Inventors: Edmund H. Christy, Robert E. Rouquette, Lawrence Van Doren