NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: FOGs
From: George Huxtable
Date: 2008 Jan 30, 23:34 -0000
From: George Huxtable
Date: 2008 Jan 30, 23:34 -0000
Lu Abel wrote- | | I am tremendously enjoying this discussion. And thanks, Frank, for the | pointer to NASA's Gravity B experiment. Its technology is truly | mind-boggling. George adds- Me too. I hope the thread will continue, and perhaps expand. However, the link to the Gravity B experiment came from Paul Hirose, not Frank. And it leads to a further question- That article, http://einstein.stanford.edu/sitemap.html , was written in the future tense, describing a proposed experiment which was intended to launch in 2003, and last for two years. So by now it should have been-and-gone. Can anyone tell us whether it actually happened, an if so, what the results were? Just as Lu describes, there's a combination of technologues in that experiment that is indeed mind-boggling. The bit that tickles me best is the notion of floating the spinning ball within the spherical cavity, by accelerating the spacecraft about, with puffs of gas, to keep it centralised. That certainly puts the egg-and-spoon race in the shade. ========================= Knowing little about the optical versions of these gyros, I had asked- "... isn't it the case that there is effectively zero long-term drift in the orientation sensing of these devices; quite different from the behaviour of their mechanical predecessors?" And Frank responded- "No, they drift for many little reasons." I would like to know a bit more than that, if anyone can tell me. What, roughly is the current limit on the long-term drift of a ring laser gyro, suitably "dithered"? And how does it differ from that of a fibre-optic gyro? George. contact George Huxtable at george@huxtable.u-net.com or at +44 1865 820222 (from UK, 01865 820222) or at 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK. --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to NavList@fer3.com To , send email to NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---