Electronic direction finder

• US 5,173,709 A
• Filed: 06/03/1991
• Issued: 12/22/1992
• Est. Priority Date: 06/03/1991
• Status: Expired due to Term

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Menick, Ralph E., Lauro, George L.
• Primary Examiner(s): Issing, Gregory C.
• Application Number:
  US07/710,197
• Time in Patent Office: 568 Days
• Field of Search: 342/357, 342/443, 342/419, 364/444, 364/449, 340/988, 340/985, 340/944, 340/870.15, 33/319, 33/320, 33/324, 33/349
• US Class Current: 342/443
• CPC Class Codes: G01C 17/30 Earth-inductor compasses
• CPC Class Codes: G01S 19/13 Receivers
• CPC Class Codes: G01S 19/51 Relative positioning

Abstract

An electronic direction finder (10) includes a navigation receiver (28) and a compass (32) to generate a bearing signal that indicates that direction of a desired destination. The bearing signal is received by a display driver (34) which causes an electronic display (14) to generate a visible image of a rotatable pointer that points in the direction of the user'"'"'s desired destination. Preferably, the display also shows an electronic compass card indicating the direction of north.

Claims

1. A portable electronic direction finder for directing a user toward a user selectable destination, comprising:

means including a navigation receiver and a compass for generating a direction signal indicative of a bearing toward the destination, the bearing being relative to the user'"'"'s heading;

an electronic display; and

a display driver coupled to the electronic display and responsive to the direction signal and to the compass for causing the electronic display to generate a pair of simultaneous visible images, one image being a compass card illustrating at least one actual compass direction, and the other image being a linear rotatable pointer which points in the direction of the user selectable destination relative to the user'"'"'s heading.

2. An electronic direction finder as set forth in claim 1 wherein the compass card has a center, and wherein the pointer image rotates about an axis that is substantially aligned with the center of the compass card.

3. A portable electronic direction finder, comprising:

input means permitting a user to input data indicative of a desired destination;

a GPS receiver which responds to the input data for generating a bearing signal indicative of a bearing relative to north (Angle B) from the user'"'"'s present position to the desired destination;

a compass for generating a heading signal indicative of the user'"'"'s heading (Angle A) relative to north;

means receiving the bearing signal and the heading signal for generating therefrom a direction signal indicative of the direction, relative to the user'"'"'s heading, of the desired destination; and

means including a display, responsive to the direction signal and to the heading signal, for simultaneously generating two images, one image being an image of a linear pointer which points in the direction of the desired destination relative to the user'"'"'s heading, and the other image being a compass card that illustrates actual compass directions.

4. An electronic direction finder, comprising:

input means permitting a user to input data indicative of a desired destination;

a GPS receiver which responds to the input data for generating a bearing signal indicative of a bearing relative to north from the user'"'"'s present position to the desired destination;

a flux-gate compass for generating a heading signal indicative of the user'"'"'s heading relative to north;

means receiving the bearing signal and the heading signal for generating therefrom a direction signal indicative of the direction, relative to the user'"'"'s heading, of the desired destination;

an electronic display; and

a display driver coupled to the electronic display and responsive to the heading signal for causing the electronic display to generate a visible image of a compass card having a center and illustrating actual compass directions, and responsive to the direction signal for causing the electronic display to generate a simultaneous visible image of an arrow that is rotatable about an axis that is substantially aligned with the center of the compass card, and for causing the arrow to point in the direction of the desired destination relative to the user'"'"'s heading, irrespective of changes in the user'"'"'s heading.