US 5,146,231 AGranted

Electronic direction finder

AssigneeMotorola, Inc.

InventorsSanjar Ghaem, George L. Lauro, Michael Barnea

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Abstract

An electronic direction finder (10), having a housing (11) with a major axis (18), has a GPS receiver (28) and directional (31) and omnidirectional (30) antennas and provides an electrical signal (angle A) indicative of the direction of the housing axis (18) with respect to a predetermined compass heading (North). The electrical signal (angle A) is provided by using determined positions of the GPS receiver (28) and one GPS satellite to calculate a compass bearing from the receiver (28) to the one satellite and using the directional antenna (31) to determine the orientation of the housing axis (18) with respect to the satellite. This eliminates using electrical output terrestrial magnetism sensing devices to sense direction finder/receiver orientation with respect to compass direction, and therefore avoids the inaccuracies and costs associated with such magnetism sensing devices.

Claims20

Dependent claims

Electronic direction finder comprising:

a housing having a major axis;
an omnidirectional antenna for receiving signals from at least three satellites;
navigation receiver fixed within said housing and coupled to said omnidirectional antenna for receiving said satellite signals from said omnidirectional antenna and in response thereto determining the position of the receiver and also determining the position of at least one of the satellites;
directional antenna means, having a directional antenna pattern, fixed to and rotatable with said navigation receiver for also providing said satellite signals to said receiver;
direction means for determining when said directional antenna pattern is oriented at a predetermined direction with respect to said at least one satellite;
and
means for providing an electrical signal indicative of the direction of said housing axis with respect to at least one predetermined compass heading when said directional antenna pattern is oriented at said predetermined direction by using the determined positions of said at least one satellite and of said receiver to calculate a bearing from said receiver to said at least one satellite.

4 more elements

Electronic direction finder comprising:

a housing having a major axis;
an omnidirectional antenna for receiving signals from at least three satellites;
GPS navigation receiver fixed within said housing and coupled to said omnidirectional antenna for receiving said satellite signals from said omnidirectional antenna and in response thereto determining the position of the receiver and also determining the position of at least one of the satellites;
directional antenna means, having a directional antenna pattern, fixed to and rotatable with said navigation receiver for also providing said satellite signals to said receiver;
direction means for determining when said directional antenna pattern is oriented at a predetermined direction with respect to said at least one satellite;
means for providing an electrical signal indicative of the direction of said housing axis with respect to at least one predetermined compass heading when said directional antenna is oriented at said predetermined direction by using the determined positions of said at least one satellite and of said receiver to calculate a bearing from said receiver to said at least one satellite;
and
display means coupled to said navigation receiver for providing, in accordance with said electrical signal, a visual indication of the orientation of said housing axis with respect to said one predetermined compass heading.

5 more elements

Electronic direction finder comprising:

a housing having a major axis;
an omnidirectional antenna for receiving signals from at least three satellites;
GPS navigation receiver fixed within said housing and coupled to said omnidirectional antenna for receiving said satellite signals from said omnidirectional antenna and in response thereto determining the position of the receiver and also determining the position of at least one of the satellites;
directional antenna means, having a directional antenna pattern, fixed to and rotatable with said navigation receiver for also providing said satellite signals to said receiver;
direction means for determining when said directional antenna pattern is oriented at a predetermined direction with respect to said at least one satellite;
and
means for providing an electrical signal indicative of the direction of said receiver axis with respect to at least one predetermined compass heading when said directional antenna is oriented at said predetermined direction by using the determined positions of said at least one satellite and of said receiver to calculate a bearing from said receiver to said at least one satellite;
wherein said directional antenna pattern has at least one narrow band null and wherein said direction means determines when said narrow band null is directed towards said at least one satellite, wherein said navigation receiver is dimension so as to be hand holdable, and wherein said navigation receiver includes display means for providing a visual indication indicative of when said housing axis is oriented at said predetermined direction with respect to said at least one satellite.

5 more elements

Dependencies are inferred from the claim text.