Fast acquisition position reporting system
US6243648A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 12, 1999 |
| Grant date | Jun 5, 2001 |
| Priority date | — |
| Expiry date | Jul 12, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S19/40
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A geographic tracking system with minimal power and size required at the mobile terminal collects observation data at the mobile terminal, forwards the data to a processor, which calculates the position. The mobile terminal needs only to gather a few milliseconds of observation data, and to relay this observation data to the processor. The range from the satellite (or other airborne transponder) to the terminal is determined using the known positions of an interrogating transmitter and a satellite, and a known terminal delay between the received signal and the transmission of the return signal, and the round trip time. An arc of locations is determined by computing an intersection of a sphere centered at the satellite having a radius given by the calculated range with a model of the Earth's surface. Only that portion of the arc within the region bounded by the satellite beam pattern is retained. Next, the time when the mobile terminal collected the GPS signal is determined. A satellite orbit model estimates the positions of the GPS satellites at their time of transmission. Using discrete points on the arc as an initial guess, an iterative least squares technique fits the observatio…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.