Apparatus and method for synchronizing the signal averaging clock of a Loran C. receiver to the clock of a Loran C. transmitter
US4999638A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 6, 1990 |
| Grant date | Mar 12, 1991 |
| Priority date | — |
| Expiry date | Mar 6, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG04G7/02
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Radio signals containing Loran C pulses from stations from a desired chain are amplified, filtered and ensembled averaged in an acquisition memory which is accessible by a controlling microprocessor. By staggering the ensemble averaging of the first four pulses in a station pulse group in time with respect to the last four pulses of the same pulse group, cross correlating the composite pulses formed by averaging the first four and last four pulses of the station pulse group with the help of the microprocessor provides time skew information which is used to adjust the receiver's master clock to align it with the clock of the transmitter. By varying the amount of time stagger, an ever finer resolution adjustment range is achieved. When the staggered averaging cycle times would exceed the time between successive ensemble averaging cycles without stagger, then successive ensemble averaging cycle time is employed for master clock adjustment. Cross correlation of the composite pulse formed by averaging the eight pulses gathered during the most recent unstaggered averaging cycle with the composite pulse averaged from the eight pulses of the previous average cycle can then be used to yield…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.