Vehicle tracking system employing global positioning system (GPS) satellites
US5225842A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 9, 1991 |
| Grant date | Jul 6, 1993 |
| Priority date | — |
| Expiry date | May 9, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S5/0009
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A tracking system employing global positioning system (GPS) satellites provides extremely accurate position, velocity, and time information for vehicles or any other animate or inanimate object within any mobile radio communication system or information system, including those operating in high rise urban areas. The tracking system includes a sensor mounted on each object, a communication link, a workstation, and a GPS reference receiver. The sensor operates autonomously following initialization by an external network management facility to sequence through the visible GPS satellites, making pseudo range and delta range or time difference and frequency difference measurements. No navigation functions are performed by the sensor, thereby permitting significant reductions in the cost thereof. The raw satellite measurements, with relevant timing and status information, are provided to the communication link to be relayed periodically back to the workstation. Differential corrections may also be provided at the workstation to increase the accuracy of the object location determination. In normal operation, three satellite measurements are required to compute the location of the object, …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.