Patent ID: 7522999

Claim:
A navigation system comprising: (a) a means for identifying an origin, (b) an inertial reference frame comprising mutually exclusive orthogonal axes X, Y, and Z, (c) a triad of linear accelerometers wherein the sensitive axis of each linear accelerometer is aligned exclusively with one axis of said inertial reference frame, (d) a tilt-rate sensor wherein said tilt-rate sensor senses a rotation about said axis X and a rotation about said axis Y of said inertial reference frame, (e) a yaw-rate sensor wherein said yaw-rate sensor senses a rotation about said axis Z of said inertial reference frame, (f) a processor means for computing a composite direction of travel based on a triad of linear accelerations from said triad of linear accelerometers, a tilt-rate from said tilt-rate sensor, and a yaw-rate from said yaw-rate sensor, and updating said computation at regular time intervals; and (g) a processor means for mathematically calculating a direction of travel to said origin from said composite direction of travel.