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Passive Homing and Hovering Control System

IP.com Disclosure Number: IPCOM000079403D
Original Publication Date: 1973-Jun-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 41K

Publishing Venue

IBM

Related People

Henrich, JE: AUTHOR

Abstract

This is a system for hovering and homing control which provides a three-dimensional position, by passive reception of three signals using interferometer techniques.

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Passive Homing and Hovering Control System

This is a system for hovering and homing control which provides a three- dimensional position, by passive reception of three signals using interferometer techniques.

Current techniques typically employ active ranging and/or direction finding from a single transmitter. However, hovering control is tightly coupled to vehicle altitude. The present technique allows the position fix to be made uncoupled from vehicle altitude and by using interferometer techniques, accuracies to within a few feet may be obtained. Also, the system is passive with respect to the hovering vehicle.

Referring to Fig. 1, the ground system consists of three continuous-wave low- power transmitters. The transmitters are tuned so that the frequencies are f(o) - delta f(o), f(o), f(o) + delta f(o).

As shown in Fig. 2, the avionics system consists of a crossed base line interferometer, which measures six phases from the combination of two base lines and three frequencies. These six phases are then converted via a small avionics computer to xyz coordinates. A digital display or elaborate cathode-ray tube (CRT) display may be used.

The operation of the system may be explained by referring to Fig. 3. Looking at Fig. 3(a), the base of the pyramid is formed by the triad of transmitters and the apex angles are determined from the interferometer measurements. Given d(1), d(2), d(3), alpha(1), alpha(1), and alpha(3) the pyramid is defined, i.e., the apex can be d...