patent for bank angle from GPS signals

Some will find this reference interesting. An underlying assumption
for the patent seems to be the airplane is in coordinated flight.
Isn't that an uncomfortable assumption for most of you -- slips along
a straight track would go undetected as banks, wouldn't they?


United States Patent 5451963
Link to this Page: http://www.freepatentsonline.com/5451963.html
Abstract: An apparatus for determining the bank angle of a moving
aircraft includes a receiver for receiving navigational signals from
NAVSTAR/GPS satellites in orbit about the earth, a signal processor
for demodulating the satellite navigational signals, an arrangement
for determining aircraft speed based on the navigational signals, an
arrangement for determining the rate of change of the aircraft track
heading from the navigational signals, an arrangement for determining
the bank angle of the moving aircraft from the aircraft speed and the
rate of change of track heading wherein the aircraft bank angle is
inversely proportional to the aircraft speed and directly proportional
to the rate of change of track heading.