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Ward, R. C.

Publications and source records attributed to Ward, R. C..

5 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1974

Error analysis of householder transformations as applied to the standard and generalized eigenvalue problems

Backward error analyses of the application of Householder transformations to both the standard and the generalized eigenvalue problems are presented. The analysis for the standard eigenvalue problem determines the error from the application of an exact similarity transformation, and the analysis for the generalized eigenvalue problem determines the error from the application of an exact equivalence transformation. Bounds for the norms of the resulting perturbation matrices are presented and compared with existing bounds when known.

Ward, R. C.↗
NASA NTRS1973

An extension of the QZ algorithm for solving the generalized matrix eigenvalue problem

This algorithm is an extension of Moler and Stewart's QZ algorithm with some added features for saving time and operations. Also, some additional properties of the QR algorithm which were not practical to implement in the QZ algorithm can be generalized with the combination shift QZ algorithm. Numerous test cases are presented to give practical application tests for algorithm. Based on results, this algorithm should be preferred over existing algorithms which attempt to solve the class of generalized eigenproblems where both matrices are singular or nearly singular.

Ward, R. C.↗
NASA NTRS1973

Laser ranging system with 1-cm resolution.

A laser ranging system has been developed in which an image converter tube equipped with deflection plates is used to make a precise measurement of the fractional amount by which the time of flight of the ranging pulse exceeds an integral multiple N of the period of a stable oscillator. The value of N is determined in an auxiliary measurement. In short-range tests with a laboratory breadboard version of the system, time-of-flight uncertainties of about 45 psec were observed. The corresponding uncertainty in a range measurement is smaller than 7 mm.

Golden, K. E.↗
NASA NTRS1973

A novel laser ranging system for measurement of ground-to-satellite distances

A technique was developed for improving the precision of laser ranging measurements of ground-to-satellite distances. The method employs a mode-locked laser transmitter and utilizes an image converter tube equipped with deflection plates in measuring the time of flight of the laser pulse to a distant retroreflector and back. Samples of the outgoing and returning light pulses are focussed on the photocathode of the image converter tube, whose deflection plates are driven by a high-voltage 120 MHz sine wave derived from a very stable oscillator. From the relative positions of the images produced at the output phosphor by the two light pulses, it is possible to make a precise determination of the fractional amount by which the time of flight exceeds some large integral multiple of the period of the deflection sinusoid.

Golden, K. E.↗