Inertial Position Determination Under Vibration

The main purpose of navigation systems is a position determination different moving objects. For standard inertial navigation systems algorithm, the initial position data are required. Normally these data may be determined by astronomical techniques or satellite and radio navigation systems. However, astronomical techniques depend on climate conditions and satellite and radio systems can be disturbed by electromagnetic countermeasures. It is proposed to use an Inertial Measurement Unit (IMU) and a navigation computer for autonomous determination of an initial position. IMU should be composed of three accelerometers, three gyroscopes and a signal processing circuit. The method proposed the latitude determination uses projections of the Earth’s rate measured by orthogonal IMU gyroscopes and projections of the gravity acceleration measured by orthogonal IMU accelerometers. Experimental tests of the IMU with a ring laser gyros triad and precision pendulum accelerometers confirmed the efficiency of the method on a fixed base. The behavior of the latitude determination under vibration is researched. The latitude determination under vibration was considered analytically by Power Spectral Density theory. It was estimated a variance of the latitude under the broad-band vibration. The method operability under harmonic and random vibration of the base at the real time is considered.