Doppler-inertial ground velocity indicator

Claim 1

A DOPPLER-INERTIAL GROUND VELOCITY INDICATOR FOR USE IN A MOVING VEHICLE, COMPRISING: A DOPPLER VELOCITY COMPUTER; A STABLE PLATFORM CONTAINING A GYROSCOPE PIVOTALLY MOVABLE ABOUT FIXED REFERENCE AXES OF VEHICLE HEADINGLY AND DRIFT MOTION; ACCELEROMETERS OPERATIVELY MOUNTED ON SAID PLATFORM; SAID ACCELEROMETERS BEING ORIENTED TO DETECT ACCELERATIONS PARALLEL TO SAID REFERENCE AXES AND PROVIDE OUTPUT SIGNALS PROPORTIONAL TO THE HEADING AND DRIFT ACCELERATIONS; INTEGRATORS CONNECTED TO SAID ACCELEROMETERS TO CONVERT THE ACCELERATION SIGNALS TO VELOCITY SIGNALS; SAID COMPUTER HAVING OUTPUTS PROVIDING DIRECTIONAL VELOCITY SIGNALS COMPARABLE TO THOSE FROM SAID INTEGRATORS; A VELOCITY COMPARATOR HAVING MEANS TO COMPARE THE VELOCITY SIGNALS FROM SAID COMPUTER OUTPUTS WITH THOSE FROM SAID INTEGRATORS AND TO PRODUCE OUTPUT ERROR SIGNALS PROPORTIONAL TO THE DIFFERENCES BETWEEN THE COMPARABLE VELOCITY SIGNALS; SAID GYROSCOPE HAVING ERECTING MEANS COUPLED TO SHIFT THE GYROSCOPE ABOUT SAID REFERENCE AXES; AND MEANS TO APPLY THE OUTPUT ERROR SIGNALS FROM SAID VELOCITY COMPARATOR TO SAID ERECTING MEANS TO ERECT THE GYROSCOPE AND COMPENSATE FOR ACCELERATIONS OF THE VEHICLE.