Apparatus and method for receiving and proessing Loran signals
US4814771A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 28, 1987 |
| Grant date | Mar 21, 1989 |
| Priority date | — |
| Expiry date | Sep 28, 2007 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S1/245
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A radio signal containing Loran C pulses from stations of interest is received and periodically sampled to convert the input signal to sample data. The data is assigned to memory locations within an acquisition memory at positions in the memory which correspond to specific times within the group repetition interval (GRI) of the Loran chain of interest. A GRI counter assigns the locations in the memory to which the data are written and cycles the memory after the completion of each GRI so that new data corresponding to a new set of pulses from the master and secondary stations of the Loran C chain will be assigned to essentially the same memory locations as data acquired during a previous GRI. The new data is ensemble averaged with the old data contained in the memory locations and the averaged data stored back in the memory. As data is collected and averaged over a sufficient number of GRI's, any signals present in the received radio signal which are not synchronous with the GRI will tend to be averaged out, improving the signal to noise ratio of the Loran C pulses in the memory. Averaging of the sampled input signal over several GRI's in this manner minimizes the effect of sporadi…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.