I thought they weighed in at around $20 k; didn't Johns cost that? I think that's fairly expensive. Are there cheaper ones? I was wondering about how to do guidance for an orbital capable vehicle I'm thinking about. Probably need under a degree accuracy over 5 minutes.
I don't really see the problem with FOGs. They're not particularly expensive when you get anywhere above the scale we're working at now,
The cheap KVH FOG gyros were $1.5k per axis. The fully-integrated-and-compensated, digital output, 6DOF Crossbow FOG unit was $9,500, but their new-and-improved model just bumped the price to $11,500.
The non-fog crossbow 6DOF IMUs were $3995 for the 400 series, and $2995 for the 300 series.
"solid state" gyros should perform much better than the 1 deg/sec that tuning-fork style gyros like the gyration parts get. I am certainly interested in hearing results from work with them.
I believe they have a drift around 1 degree/second, great if you have GPS to compare against, but GPS capable of orbital velocity cost $10k or so?and for our current scale, decent solid state gyros should work fine ($50-$150 range).
When you have a vehicle capable of orbital velocity, $10k won't be a problem.
In any case, GPS by itself doesn't let you re-sync your gyros, you need a multi-antenna GPS attitude sensing system, not just a position output GPS.
John Carmack
