Showing papers on "Inertial reference unit published in 1974"
Patent•
17 Jun 1974TL;DR: In this article, a redundant inertial measuring system includes three strapdown platforms each having two inertial sensors and the sensitive axes of the sensors are discretely disposed relative to the faces of a dodecahedron.
Abstract: A redundant inertial measuring system includes three strapdown platforms each having two inertial sensors. The sensitive axes of the sensors are discretely disposed relative to the faces of a dodecahedron. The sensors and their associated electronics are physically and electrically separated from each other within each of the platforms.
10 citations
TL;DR: The drift rates observed on these inertial grade gyros during the 1½ year of in-orbit operation have remained within a band of 16 arcsec per hour peak-to-peak as discussed by the authors.
Abstract: The Inertial Reference Unit (IRU) used in NASA's Orbiting Astronomical Observatory (OAO-C or Copernicus) uses three single degree of freedom, floated, rate-integrating gyros operated in binary, pulse-restrained torque loops to provide an inertial attitude reference for the spacecraft's altitude control system. Since 21 August 1972 when the spacecraft was launched, more than 15,000 hours of continuous and troublefree operation have been accumulated on the IRU. When prelaunch operation is included, the running times for the gyro wheels range between 17,000 and 22,000 hours.
The drift rates observed on these inertial grade gyros during the 1½ year of in-orbit operation have remained within a band of 16 arcsec per hour peak-to-peak When the effects of known disturbances are considered, the standard deviation of drift rate appears to approach one arcsec per hour (≤10−7 degrees per second).
Included in this paper are a brief description of the OAO and IRU, a summary of the data reduction programs used to calibrate the IRU in orbit, and some thoughts on how gyros with good long-term drift stability could be applied to future spacecraft such as the Large Space Telescope and Earth Observatory Satellite.
3 citations
17 Dec 1974
TL;DR: The book is devoted to the theory of autonomous inertial systems, an analysis of which permits evaluation of the operating stability of the system and establishment of the relationship between the errors of the elements and the accuracy of determining the navigational parameters of the object: the current coordinates of position and its orientation in space.
Abstract: : The main attention is devoted to the equations of ideal operations (unperturbed functioning) of inertial systems, which determine their structure, and to equations of inertial navigation system errors, an analysis of which permits evaluation of the operating stability of the system and establishment of the relationship between the errors of the elements and the accuracy of determining the navigational parameters of the object: the current coordinates of position and its orientation in space. Problems of autonomous preparation of inertial systems for operation are also considered. The book is devoted to the theory of autonomous inertial systems.
3 citations
01 Aug 1974
TL;DR: The incorporation of precision inertial control on LST could exert a strong influence on the philosophy of and techniques for carrying out astronomical observations as discussed by the authors, which could easily expand LST capability to include observations such as tracking of solar system objects, including specific points of interest on the planets, rapid repositioning of scanning sensors on distributed objects such as nebulae and galaxies, and carrying out unified star catalog measurements to eliminate the overlap problem which exists in all ground procedures.
Abstract: The incorporation of precision inertial control on LST could exert a strong influence on the philosophy of and techniques for carrying out astronomical observations. In conjunction with a fine guidance star sensor, the inertial reference unit (IRU) described herein could easily expand LST capability to include observations such as (1) tracking of solar system objects, including specific points of interest on the planets; (2) rapid repositioning of scanning sensors on distributed objects such as nebulae and galaxies; (3) carrying out unified star catalog measurements to eliminate the overlap problem which exists in all ground procedures; and (4) carrying out various astrometric measurements with 'real time' data reduction capability.
2 citations
01 Mar 1974
TL;DR: The theory, development, and test evaluations of the Strapdown Inertial Reference Unit (SIRU) are discussed in this article, where statistical failure detection and isolation, single position calibration, and self alignment techniques are emphasized.
Abstract: The theory, development, and test evaluations of the Strapdown Inertial Reference Unit (SIRU) are discussed. The statistical failure detection and isolation, single position calibration, and self alignment techniques are emphasized. Circuit diagrams of the system components are provided. Mathematical models are developed to show the performance characteristics of the subsystems. Specific areas of the utilization program are identified as: (1) error source propagation characteristics and (2) local level navigation performance demonstrations.
2 citations
Patent•
25 Mar 1974
TL;DR: In this paper, the authors combined means for sensing an inertial condition and for providing torquing and damping functions for controlling the response of the device to the condition, such as a rate gyro, accelerometer or like device.
Abstract: For use with an inertial sensing device such as a rate gyro, accelerometer or like device, combined means for sensing an inertial condition and for providing torquing and damping functions for controlling the response of the device to the condition.
2 citations
05 Aug 1974
1 citations
15 Sep 1974
TL;DR: The attitude control logic in conjunction with command inputs from other spacecraft subsystems establishes the attitude control operating mode as discussed by the authors, which utilizes Sun and Canopus acquisition signals generated within the ACS to perform automatic mode switching so that dependence of ground control is minimized when operating in the sun acquisition, roll search, and celestial cruise modes.
Abstract: The Mariner Mars 1971 attitude control subsystem (ACS) is discussed. It is comprised of a sun sensor set, a Canopus tracker, an inertial reference unit, two cold gas reaction control assemblies, two rocket engine gimbal actuators, and an attitude control electronics unit. The subsystem has the following eight operating modes: (1) launch, (2) sun acquisition, (3) roll search, (4) celestial cruise, (5) all-axes inertial, (6) roll inertial, (7) commanded turn, and (8) thrust vector control. In the celestial cruise mode, the position control is held to plus or minus 0.25 deg. Commanded turn rates are plus or minus 0.18 deg/s. The attitude control logic in conjunction with command inputs from other spacecraft subsystems establishes the ACS operating mode. The logic utilizes Sun and Canopus acquisition signals generated within the ACS to perform automatic mode switching so that dependence of ground control is minimized when operating in the sun acquisition, roll search, and celestial cruise modes. The total ACS weight is 65.7 lb, and includes 5.4 lb of nitrogen gas. Total power requirements vary from 9 W for the celestial cruise mode to 54 W for the commanded turn mode.
1 citations
23 Sep 1974
TL;DR: In this paper, three different rebalance electronic loops were designed, implemented, and evaluated using width-modulated binary types using a 614.4 kHz keying signal; they were developed to accommodate the following three inertial sensors with the indicated resolution values.
Abstract: Three different rebalance electronic loops were designed, implemented, and evaluated. The loops were width-modulated binary types using a 614.4 kHz keying signal; they were developed to accommodate the following three inertial sensors with the indicated resolution values: (1) Kearfott 2412 accelerometer - resolution = 260 micro-g/data pulse, (2) Honeywell GG334 gyroscope - resolution = 3.9 milli-arc-sec/data pulse, (3) Kearfott 2401-009 accelerometer - resolution = 144 milli-g/data pulse. Design theory, details of the design implementation, and experimental results for each loop are presented.
1 citations
30 Nov 1974
TL;DR: Analysis and data reduction techniques are developed to determine the attitude of the Ute-Tomahawk rocket A09.209-1, fired 16 April 1973 at White Sands Missile Range, New Mexico.
Abstract: : The implementation of procedures used to calculate the attitude of a rocket from its transmitted gyroscopic roll, pitch, and yaw signals is discussed The differences and the angular conversions of the output from various inertial attitude systems are presented Also, a synopsis of the mathematical analysis used to compute attitude is presented In addition, analyses and data reduction techniques are developed to determine the attitude of the Ute-Tomahawk rocket A09209-1, fired 16 April 1973 at White Sands Missile Range, New Mexico