Networked differential GPS system
US5323322A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 5, 1992 |
| Grant date | Jun 21, 1994 |
| Priority date | — |
| Expiry date | Mar 5, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S19/32
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An 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 accompli…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.