Apparatus and method for encoding and decoding data on tactical air navigation and distance measuring equipment signals
US5691723A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 11, 1995 |
| Grant date | Nov 25, 1997 |
| Priority date | — |
| Expiry date | Sep 11, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S19/41
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method and apparatus for encoding and decoding data on navigation signal pulse pairs utilizes pulse position modulation (PPM). The pulse interval between a first pulse and a second pulse of the pulse pair is varied depending on whether the logic value of the data to be encoded is a logic "0" or a logic "1". A tri-graph encoding process converts the raw input data into encoded input data. Each input data bit is encoded into three bits with each bit having the same logical value as the input data bit. The encoded input data is then encoded on the navigation signal using a pulse position modulation (PPM) technique. A decoder recovers the encoded data and provides an error correction process for high data integrity that corrects certain bit errors that may occur during the transmission and reception of the data on the navigation signal. The error correction process detects and corrects errors such as a missing bit, an extra bit or a bit error.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.