| Title | Medium-Frequency Data Link for Differential NAVSTAR/GPS Broadcasts |
|---|---|
| Record ID | 50479 |
| Personal Name Creator |
Enge, Per K.; Ruane, Michael F.; Sheynblatt, Lee |
| Source | 86p. in various pagings |
| Corporate Creator | John A. Volpe National Transportation Systems Center (U.S.) |
| Corporate Contributor |
United States. Coast Guard. Office of Navigation Safety and Waterway Services |
| Publisher | United States. Coast Guard |
| Publication Date | 19860601 |
| Language | English |
| Abstract | Differential GPS must communicate differential corrections to civilian users of the Global Positioning System. Modulation of existing marine radiobeacons can provide the needed communication link for DGPS, provided the operation of existing radiobeacon direction finding equipment is maintained ad adequate DGPS range is provided in the presence of atmospheric noise and skywave fading. Existing DF and ADF units were studied through a manufacturers' survey, and a radiobeacon modulation scheme has been proposed that maintains reliable DF and a ADF operation. MSK modulation with a frequency offset of 325 Hz is recommended, with a power offset of -3dB. This scheme limits ADF bearing errors to under 3 deg based on analysis of the modulation energy entering the effective passbands of the various ADF designs. CCir data on atmospheric noise and multipath were studies and a rate 1/2 convolutional code with constraint length 6 is recommended to provide a DGPS bit error probability of less than 0.00001. Reliable DGPS range for 10 nautical mile beacons will be 100 km, and for 30 nm beacons, 195 km. Discussion of interleaving to control atmospheric burst noise is included. |
| Rosap ID | dot:11865 |
| Rosap URL | https://rosap.ntl.bts.gov/view/dot/11865 |
| TRT Terms | Aids to navigation; Navigation; Radio beacons; Global Positioning System; Modulation |
| General Subjects | Data link; Differential Global Positioning System; Direction finding; Ocean surface; Multipath transmission |
| Classification | NTL - MARINE/WATERWAYS TRANSPORTATION - U.S. Coast Guard; NTL - MARINE/WATERWAYS TRANSPORTATION - MARINE/WATERWAYS TRANSPORTATION; NTL - MARINE/WATERWAYS TRANSPORTATION - Marine Planning and Policy; NTL - MARINE/WATERWAYS TRANSPORTATION - Marine Safety |
| Geographical Coverage |
United States |
| Contract Number | DTRS-57-85-C-00091 |
| Report Number | DOT/CG/N/02-86; DOT-TSC-CG-86-01 |
| Resource type | Tech Report |
| URL | https://ntlrepository.blob.core.windows.net/lib/50000/50400/50479/DOT-TSC-CG-86-01.pdf |
| Format | |
| Database | NTL Digital Repository |