Comment Re:Spacecraft, aircraft, commercial vehicles... (Score 1) 91
Gravity Probe B had what i believe is at least a comparable spec of gyroscope:
http://einstein.stanford.edu/TECH/technology1.html
"The SQUID magnetometers are so sensitive that a field change of only one quantum—equivalent to 5 x 10-14 gauss (1/10,000,000,000,000th of the Earth's magnetic field) and corresponding to a gyro tilt of 0.1 milliarcsecond (3x10-8 degrees)—is detectable. "