The Charles Stark Draper Laboratory, Inc.

Jeffrey A Volp

Glenn Mamon

Douglas G Youmans

A fault-tolerant power distribution system which includes a plurality of power sources and a plurality of nodes responsive thereto for supplying power to one or more loads associated with each node. Each node includes a plurality of switching circuits, each of which preferably uses a power field effect transistor which provides a diode operation when power is first applied to the nodes and which thereafter provides bi-directional current flow through the switching circuit in a manner such that a low voltage drop is produced in each direction. Each switching circuit includes circuitry for disabling the power field effect transistor when the current in the switching circuit exceeds a preselected value.

Fault-tolerant power distribution system

A system for determining the range between a reference point and a target by transmitting a pulse toward the target and measuring the time until receipt of a pulse reflected by the target. In an airborne laser altimeter configuration, the reference point may be located on an aircraft and a pulsed laser is directed along a vertical path to the ground. The system measures the duration of a pulse sequence including a first (or start) pulse, representing a pulse transmitted from the reference point, and the last of one or more associated subsequent return pulses, where the return pulses represent reflections of the transmitted pulse from both the ground and interfering objects located between the reference point and the ground. The system generates a replica of the start pulse and subsequent pulses, with the replica being delayed by a predetermined period from the start pulse and associated subsequent return pulses. The undelayed pulse sequence is processed to determine the number of return pulses in that sequence, and this detected number of pulses is utilized to enable a gate which passes only the last return pulse in the delayed pulse sequence. A time interval measurement is performed by a single precision time interval counter which is initiated by the start pulse of the delayed pulse sequence and is disabled by the gated last, or stop, pulse of the delayed pulse sequence.

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Billerica, MA, United States of America

Jeffrey A Volp