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A general description of the st124-m inertial platform system
General description of ST-124-M inertial platform system
The adaptation of a strap down formulation for processing inertial platform data
An estimator propagation formulation which ultilizes dynamic data (attitude and sensed acceleration information) from a gimballed inertial platform has been developed to aid in the Shuttle post-flight trajectory reconstruction process and aerodynamic coefficient determination studies. Unlike the classical inertial algorithms, this formulation yields a six degree-of-freedom fully coupled state and attitude estimate. Furthermore, this inertial version is shown to be independent of initial unknown platform misalignments. Results obtained using actual Inertial Measurement Unit (IMU) data and Aerodynamic Coefficient Identification Package (ACIP) strap down data from Shuttle flights are presented.
Venus swingby trajectories, estimation of inertial platform errors, interplanetary navigation and guidance analysis
Trajectory calculations for Venus swingby trajectories, interplanetary navigation and guidance analysis, and inertial platform errors
Design and simulation of closed-loop ground alignment of inertial platforms with sway motion
This paper is concerned with the application of optimal estimation and control concepts to the ground alignment of inertial platforms subjected to random sway motion. A seventh-order Kalman filter has been designed for estimating the platform misalignments and sway motion. Using the linear quadratic optimal regulator techniques, feedback controller gains have been designed to drive the initial misalignments to a small value. A reconfiguration of the filter controller scheme has been proposed and verified by Monte Carlo simulation for improving the speed of alignment without changing the alignment accuracy.
Computer-aided inertial platform realignment in manned space flight.
Hardware design and functions of Apollo guidance and navigation system for inertial measurement unit realignment, outlining computer programs and routines
A derivation of the three dimensional three degree of freedom re-entry equations of motion in terrestrial navigational coordinates with subsequent resolution into inertial platform coordinates
Derivation of three-dimensional three-degree-of- freedom reentry equations of motion in terrestrial navigational coordinates
Gas supply system for the ST-124 inertial platform
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Adaptation of a strapdown formulation for processing inertial platform data
Previously cited in issue 19, p. 2991, Accession no. A82-39108
An introduction to analytic platforms for inertial guidance
Analytic platform inertial navigation system using single axis reference and pendulous integrating gyro accelerometer measuring devices
Optical alignment of Centaur's inertial guidance system
During Centaur launch operations the launch azimuth of the inertial platform's U-accelerometer input axis must be accurately established and maintained. This is accomplished by using an optically closed loop system with a long-range autotheodolite whose line of sight was established by a first-order survey. A collimated light beam from the autotheodolite intercepts a reflecting Porro prism mounted on the platform azimuth gimbal. Thus, any deviation of the Porro prism from its predetermined heading is optically detected by the autotheodolite. The error signal produced is used to torque the azimuth gimbal back to its required launch azimuth. The heading of the U-accelerometer input axis is therefore maintained automatically. Previously, the autotheodolite system could not distinguish between vehicle sway and rotational motion of the inertial platform unless at least three prisms were used. One prism was mounted on the inertial platform to maintain azimuth alignment, and two prisms were mounted externally on the vehicle to track sway. For example, the automatic azimuth-laying theodolite (AALT-SV-M2) on the Saturn vehilce used three prisms. The results of testing and modifying the AALT-SV-M2 autotheodolite to simultaneously monitor and maintain alignment of the inertial platform and track the sway of the vehicle from a single Porro prism.
Long-duration life tests of slip ring capsule assemblies for inertial guidance platforms
Eight slip ring capsules, each having 80 or 100 circuits, were operated for time periods ranging from 14,300 hours to 24,700 hours. The test mode simulated the motion of gimbal axes of the Saturn inertial guidance the platform in an organic free nitrogen environment. Computer-compiled noise data (approximately 45,000 recordings) were graphed as a function of test time and position within the capsules and as extreme probability distributions. Greater than ninety-nine percent of the noise measurements for the capsules with sufficient lubrication were less than 10 milliohms. Capsules with glass dielectrics did not perform significantly differently than those with filled epoxy dielectrics. The initial wear mode of prow formation was followed by rider wear. After 10 to the 8th power wipes, ring wear depth did not exceed the surface finish and the radial rider wear depth was less than 13 microns.
Angle of attack estimation using an inertial reference platform
This paper presents the mathematical development and flight test results of an angle of attack estimation system based on inertial navigation system inputs. The estimator uses these inputs to determine the coefficient of lift required at any instant inflight. Angle of attack is then modeled through a regression analysis based on coefficient of lift, altitude and Mach. Overall correlation of the estimator as tested was generally within 0.5 degrees through 17 degrees angle of attack on an F-15A aircraft. A robustness analysis indicates that the system can be used adequately in maneuvering flight.
Investigations of the potential performance characteristics of selected contact lubricants for applications in miniature slip-ring capsules of the type used in ST 124 M stabilized inertial guidance platforms Final technical report, 27 Mar. 1968 - 30 Apr. 1970
Performance characteristics of liquid and solid lubricants for contacts of miniature slip-ring capsules
Application of gyrocompassing to space missions Final technical report
Gyrocompassing with sensors or inertial platforms for use on planetary surface or in free orbital flight
Dynamic testing.
Dynamic response of inertial platform systems examining comparison, growing exponential, Fourier analysis and exponential series methods of response evaluation
Determination of navigation FDI thresholds using a Markov model
A method for determining time-varying Failure Detection and Identification (FDI) thresholds for single sample decision functions is described in the context of a triplex system of inertial platforms. A cost function consisting of the probability of vehicle loss due to FDI decision errors is minimized. A discrete Markov model is constructed from which this cost can be determined as a function of the decision thresholds employed to detect and identify the first and second failures. Optimal thresholds are determined through the use of parameter optimization techniques. The application of this approach to threshold determination is illustrated for the Space Shuttle's inertial measurement instruments.
Guidance, control, and propulsion systems
In accomplishing the Gemini Program objectives, an onboard digital computer system, an inertial platform reference system, a radar system, and control systems using hypergolic bipropellant propulsion have been developed and successfully demonstrated.