Position determining apparatus and method
US4114155A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 30, 1976 |
| Grant date | Sep 12, 1978 |
| Priority date | — |
| Expiry date | Jul 30, 1996 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S19/30
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The position of a receiver responsive to C/A signals derived from multiple, orbiting space crafts is determined to an accuracy of greater than 300 meters. Each of the C/A signals has the same carrier frequency and a different, predetermined Gold code sequence that normally prevents position determination to be more accurate than to within 300 meters. C/A signals transmitted to the receiver are separately detected by cross correlating received Gold code sequences with plural locally derived Gold code sequences. Four of the detected C/A signals are combined to compute receiver position to an accuracy of 300 meters. To determine receiver position to greater accuracy than 300 meters, the relative phase of internally derived Gold code sequences is varied over the interval of one chip of each sequence, to derive second cross correlation values indicative of received and locally derived Gold code sequences; the second cross correlation values represent different positions within the computed 300 meter position. Third cross correlation values indicative of correlations between the internally derived Gold code sequences for the different positions within the computed 300 meter position are …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.