Enhanced global positioning system Delta-Range processing
Differential navigation system for remote mobile users
Method and apparatus for deriving pseudo range from earth-orbiting satellites
Geodetic surveying system using multiple GPS base stations
Exploration system and method for high-accuracy and high-confidence level relative position and velocity determinations
Vehicle tracking system employing global positioning system (GPS) satellites Patent #: 5225842
ApplicationNo. 846380 filed on 03/05/1992
US Classes:701/215, Having multiple GPS antennas or receivers (e.g., differential GPS)342/357.03, Using differential correction342/358, With satellite signal correction701/226Space orbits or paths
ExaminersPrimary: Black, Thomas G.
Assistant: Zanelli, Michael J.
Attorney, Agent or Firm
International ClassG01S 005/02
AbstractAn embodiment of the present invention relates to a worldwide network of differential GPS reference stations (NDGPS) that continually track the entire GPS satellite constellation and provide interpolations of reference station corrections tailored for particular user locations between the reference stations Each reference station takes real-time ionospheric measurements with codeless cross-correlating dual-frequency carrier GPS receivers and computes real-time orbit ephemerides independently. An absolute pseudorange correction (PRC) is defined for each satellite as a function of a particular user's location. A map of the function is constructed, with "iso-PRC" contours. The network measures the PRCs at a few points, so-called reference stations and constructs an iso-PRC map for each satellite. Corrections are interpolated for each user's site on a subscription basis. The data bandwidths are kept to a minimum by transmitting information that cannot be obtained directly by the user and by updating information by classes and according to how quickly each class of data goes stale given the realities of the GPS system. Sub-decimeter-level kinematic accuracy over a given area is accomplished by establishing a mini-fiducial network.