Showing papers on "Inertial measurement unit published in 1968"

Statistical estimation in inertial navigation systems.

Abstract: Although navigation systems have generally been developed by solving exactly the dynamic equations of motion, in reality the navigation problem is a statistical one since there are unpredictable errors in the measurements. The advent of very powerful navigation computers makes it possible by using statistical filtering techniques to retrieve more of the information contained in the navigation measurements. The navigation system is thus developed here as an information-filtering problem rather than a simulation of a deterministic physical system. The Kalman optimum linear filter is found to apply to the navigation problem if some technique is used to account for possible non-Gaussian maneuver accelerations. A major problem in the application of statistical techniques is the tremendous amount of computation required. Two methods are suggested which greatly reduce the amount of computation with a minimum degradation in the performance of the system. In one method, physical considerations are used to divide the total filter into smaller, simpler filters. In the other method, the optimum gains are precomputed and approximated by simple functions in the flight computer. The details are given for the alignment and calibration of an inertial platform using statistical filtering.

A non-orthogonal multi-sensor strapdown inertial reference unit.

Abstract: Nonorthogonal multisensor strapdown inertial reference unit providing redundant capabilities and optimal performance

Design approach for reducing gyro-induced errors in strapdown inertial systems.

Abstract: Single degree of freedom integrating gyro in strapdown inertial systems, discussing error reduction

Computer-aided inertial platform realignment in manned space flight.

Abstract: Hardware design and functions of Apollo guidance and navigation system for inertial measurement unit realignment, outlining computer programs and routines

Omega‐Inertial Hybrid Receiver

Abstract: Schuler tuned inertial data tracking OMEGA radio position data, with the difference applied to erect the inertial platform and damp Schuler oscillations, yields a Hybrid OMEGA-INERTIAL system that follows vehicle maneuver without lag, with continuous correction of vertical and azimuth. Initial alignment prior to departure is not required. Position errors are bounded by radio data, so that inertial sensors of only moderate accuracy are sufficient. After signal acquisition, the radio data is tracked with zero error through all maneuver, including signal outages of moderate duration, so that OMEGA lane count is maintained. Azimuth and attitude are available for autopilot inputs, and the system provides a Universal Time scale to microsecond accuracy.