Channel estimating reference signal processor for communication system adaptive antennas
Mobile radiotelephone station two-way ranging system
System and method for tracking targets in a multipath environment
Programming format and apparatus for the improved coherent beam coupler system and method
Remote controlled tracking transmitter and tracking support system Patent #: 4596988
ApplicationNo. 06/894867 filed on 08/08/1986
US Classes:342/457, Land vehicle location (e.g., bus, police car342/465Plural receivers only
ExaminersPrimary: Tarcza, Thomas H.
Assistant: Swann, Tod R.
Attorney, Agent or Firm
International ClassesH04Q 7/38 (20060101)
G01S 3/48 (20060101)
G01S 3/14 (20060101)
G01S 5/04 (20060101)
AbstractThe present invention combines the relative insensitivity of the phase angle differences of a radio signal to the signal distortions inherent in an urban environment with digital signal processing techniques to produce an accurate and economical way to locate a mobile transmitter station such as a mobile telephone in a cellular telephone network. Phase angle measurements indicative of the angle of direction of a mobile transmitter station from each of a plurality of land stations are obtained by translated Hilbert transformation and are processed to produce a probability density function. The probability density functions are combined after a CHI-squared analysis to produce an area of uncertainty representing the position of the mobile transmitter station. The radio frequency signals emitted from the mobile transmitter station need have no special characteristic for the localization process. Thus, the present invention may easily work as an adjunct to an unrelated communications system such as a cellular telephone system.