How did early US nuclear powered subs fix their position?

timmyg00 · 07-29-05, 05:21 PM

Technically, a "fix" is position data received from an external source (Radio signals like GPS, visual references like the stars or land features/navaids, or radar fixes), so INS, SINS, or ESGN doesn't count as a "fix"; they are just very advanced dead-reckoning systems. Basically, you enter a position from a fix into one of these systems, and the system computes your expected position based on your course and speed. I think ESGN is still the standard for advanced DR systems today.

Older systems used for position fixes included LORAN and OMEGA (Radio Nav systems at LF and VLF) and NAVSAT (a precursor to GPS). GPS and visual (when properly performed and at slow speeds) fixes are the most accurate. Anything that takes into account at least 3 external references is considered a fix (3 radar positions of fixed objects counts as well).

TG

07-29-05, 05:21 PM	#3
timmyg00 中国水兵 Join Date: Jan 2000 Location: The People's Republic of Massachusetts, USA Posts: 282 Downloads: 42 Uploads: 0	Technically, a "fix" is position data received from an external source (Radio signals like GPS, visual references like the stars or land features/navaids, or radar fixes), so INS, SINS, or ESGN doesn't count as a "fix"; they are just very advanced dead-reckoning systems. Basically, you enter a position from a fix into one of these systems, and the system computes your expected position based on your course and speed. I think ESGN is still the standard for advanced DR systems today. Older systems used for position fixes included LORAN and OMEGA (Radio Nav systems at LF and VLF) and NAVSAT (a precursor to GPS). GPS and visual (when properly performed and at slow speeds) fixes are the most accurate. Anything that takes into account at least 3 external references is considered a fix (3 radar positions of fixed objects counts as well). TG __________________ ET1/SS, SSN-760 USSVI Marblehead Base (MA) *Naval Historical Sites - Photo Galleries*