Showing papers on "Inertial reference unit published in 1969"

Inertial/doppler-satellite navigation system

Abstract: Terrestrial navigation apparatus for a vehicle includes a system of inertial sensors generating signals representative of the position and velocity of the vehicle, a data processor, and a receiver for receiving data from a doppler satellite system including a signal of known frequency as well as signals representative of the satellite''s position. The difference between the doppler frequency shift computed from the information received from the satellite and the doppler frequency shift computed by the inertial system is modeled as an observable in a Kalman filter programmed into the data processor to generate a set of error signals representative of estimates of the errors in the position and velocity signals generated by the inertial sensors. The error estimate signals are then used to correct the errors in the inertial sensors. In one disclosed embodiment, the external, observed parameter is a discrete frequency; whereas in an alternative system, it is a frequency count.

Experimental strapdown redundant sensor inertial navigation system

Abstract: Strapdown redundant experimental sensor inertial navigation package containing gyros and accelerometers, discussing signal real time processing by digital computer

Shipboard or aircraft gravity vector determination by means of a three-channel inertial navigator

Abstract: A method is suggested for using a three-channel inertial navigator in a ship or aircraft to provide accurate information on the direction and magnitude of the earth's gravity field. The principles are similar to those used to determine the earth's gravity field by observations of a satellite. The inertial navigator considered here includes a provisional model of the earth's gravity field from which the three components of gravitational acceleration are derived as functions of position. The velocity and position are outputs of the system in its normal mode of operation and they themselves, or functions of them, can be compared with corresponding values obtained from noninertial sources such as Loran. The parameters of the gravity computations and the initial conditions are then modified to produce the best agreement between computed and observed quantities. The connections between this method and existing gravimetric and astrogeodetic techniques are established.

Two-resolver, strapped-down inertial reference system

Abstract: The strapped-down reference system attains the equivalence of a three- and four-gimbal, inertial reference system by using a forward resolver chain, which can be of relatively low accuracy, to derive gimbal angle values, and high-accuracy feedback resolvers to derive signals to cage the gyroscopes. The gyroscopes are caged by pulse torque techniques and integration of angular rates is performed in an essentially digital fashion by pulse generators and stepping motors.

Analysis and evaluation of a novel inertial navigation system

Abstract: sensors. The theory of the system mechanization is develop ed from first principles and methods for calculation of the system loop gains are presented. First, a single-axis system is considered and then the analysis is generalized to a three-axis system. The analyses performed indicate that error propagation for the novel system and the conven tional system are identical for identical error sources. It is also shown that the RAMP base motion isolation syste provides a better gyro environment than that used in a con ventional system since the level gyros are not required in the gimbal servo loops. Reports of flight tests of this system corroborate these conclusions. SUMMARY A novel inertial navigation system referred to in the literature as the RAMP inertial navigator is analyzed and then compared to a conventional local vertical navigation system. The main attraction of this system is that it is capable of indicating the vertical using only gyros as sensors, The theory of the system mechanization is developed from first principles and methods for calculation of the system loop gains are presented. First, a single-axis system is considered and then the analysis is generalized to a three-axis system. The analyses performed indicate that error propagation for the novel system and the conventional system are identical for identical error sources. It is also shown that the RAMP base motion isolation system provides a better gyro environment than that used in a conventional system since the level gyros are not required in the gimbal servo loops. Reports of flight tests of this system corroborate these conclusions. fulfillment of the requirements for the degree of Master of Science.

SIRU - A new inertial system concept for inflight reliability and maintainability.

Abstract: Strapdown inertial reference unit system for inflight reliability and maintainability, discussing design and components

Designing differentiating and integrating gyroscopes and accelerometers

Abstract: : The book covers the fundamentals of analysis and designing of differentiating and integrating gyroscopes and accelerometers and an analysis of their errors under different operating conditions is given. Simple calculation formulas for determination of the basic parameters of these instruments and also their instrumental and methodical errors are given. Depending upon the assignment of the instrument, requirements for static, dynamic, and accuracy characteristics are shown. Much attention is given description of the physical essence and causes of appearance of the examined errors. (Author)

Design of Strapdown Gyroscopes for a Dynamic Environment Interim Scientific Report II

Abstract: Error analysis for single degree of freedom integrating gyro, and figure of merit relating gyro errors to orientation error of strapdown inertial reference system

On the Treatment of Inertial Measurement Unit Data in Optimal Linear Navigation Policies

Abstract: The inclusion of the integrated nongravitational acceleration outputs from an inertial measurement unit in an optimal linear navigation policy is treated. This formulation appears to be considerably different nt from the treatments of IMU data for space vehicle navigation that have previously been discussed and promises to yield considerably better results in many instances. It has the advantage that the data are processed in an optimal fashion that makes the best use of knowledge of the general system characteristics. Further, the IMU enters the formulation in the same manner as any other sensor and, therefore, provides a more uniform method of treatment. Two methods of dealing ng with the IMU are discussed and then applied to a simple example. The advantages of the second formulation are observed to be quite significant.

Error analysis of strapdown and local level inertial systems which compute in geographic coordinates

Abstract: Error analysis of strapdown and local level inertial navigation systems which compute in geographic coordinates

Strapdown navigation equations for geographic and tangent coordinate frames

Abstract: Navigation equations for geographic and tangent coordinate frames for radar strapdown inertial navigation