On 6 Feb 2007 06:40:22 -0800, "Tony" wrote in
.com:

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,


The full text of the patent is available he


http://patft.uspto.gov/netacgi/nph-P...&RS=PN/5451963
Inventors: Lempicke; Thomas A. (Rock Hill, SC)
Appl. No.: 08/249,803
Filed: May 26, 1994


It seems Mr. Lempicke has another more recent patent also:


http://patft.uspto.gov/netacgi/nph-P...&RS=PN/5841370
US Patent Issued on November 24, 1998
5841370
Method and apparatus for determining aircraft bank angle using
satellite...
An apparatus for determining the bank angle of an aircraft and
method 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 a sensitivity... 1998-11-24


I wonder why I was never taught that " ... winds can cause lateral
forces to affect the aircraft turning movement, tending to slip
the aircraft sideways."


From the summary:

An aircraft turns by banking which is caused by oppositely
deflecting ailerons. As the aircraft turns in a banking manner,
the pilot requires some visual indicator of the aircraft banking
attitude to coordinate the turn, maintain the desired course and
to safely operate the aircraft. The banking attitude is the
aircraft bank angle or angle of bank. Bank angle indicators are
common instrumentation in an aircraft and are sometimes combined
with a bubble/level device to form a combined instrument known as
a turn coordinator. The display associated with this device gives
the pilot necessary information regarding performance of a
coordinated turn. As the aircraft turns, winds can cause lateral
forces to affect the aircraft turning movement, tending to slip
the aircraft sideways. The rudder may be moved in correcting
response to lateral forces causing the aircraft to slip. The
lateral forces are displayed on the turn coordinator using the
bubble-type device similar to a carpenter's level. However, it is
the bank angle which actually defines the extent and rate of the
turn in coordination with aircraft speed. Current bank angle
indicators or turn coordinators are based on gyroscopes and use
the precession of the gyroscope in combination with a correction
factor to determine bank angle. The bank angle is displayed on the
turn coordinator using a tilting aircraft silhouette.