A heading indicator is disclosed which utilizes a one-degree-of-freedom platform stabilized by a two-degree-of-freedom dry flexure gyro. The output of one of the sensitive axis is coupled through an amplifier to the corresponding torquer in the gyro and selectively through another amplifier to the opposite torquer. The other sensitive axis output is coupled through an amplifier to the platform. The indicator initializes to true north and is then switched to a directional gyro mode.
The invention concerns a compass having an electro magnetic half-shell transformer energy transmission and opto electronic data transmission. To avoid a slipring connection during the transfer of supply voltage at least one winding on the primary half-shell is connected to a controllable input voltage source via a H-bridge circuit, and at least one secondary winding having taps is provided at the other half-shell coil.
A device is provided for enabling inertial land navigation of a vehicle, for measuring and updating vehicle heading by North-seeking and navigating. A single dual-axis gyroscope is sequenced through North-seeking, parameter calibration, and navigating by a high resolution flip table rotated by a stepper motor, without a gimballed support therefor. Inclinometers aid the gyroscope in North-seeking and parameter calibration without accelerometers therefor.
An angular rate sensor system [10] comprising a vibratory sensing element [12] and signal processing circuit [14]. The element [12] is preferably a polymorphic rectangular bar fabricated from two layers of piezoceramic material [26, 28] divided by a thin center electrode [E.sub.c ], and a plurality of electrodes [E.sub.1 -E.sub.4 ] scored onto the planar conductive surfaces [30, 32]. The element [12] is suspended at its acoustic nodes [N, N'] to vibrate in one direction [V] normal to the physical plane of the electrodes [E.sub.c, E.sub.1 -E.sub.4 ] using any suitable mounting structure such as parallel crossed filaments [34] or inwardly angled support arms [64] that provide predetermined degrees of lateral [S'] and longitudinal [S] stiffness. The circuit [14] may optionally constitute totally shared [FIG. 7], partially shared [FIG. 8], or totally isolated [FIG. 9] driving and sensing functions, the corresponding element [12] being configured with dual-pair, single-pair, or single-triple outer electrodes [E.sub.1 -E.sub.4 ], respectively. The circuit [14] typically utilizes an automatic gain control and two operational amplifiers, and may include various signal conditioning components and a separate tuning module.
