Digital compass with multiple sensing and reporting capability

• US 6,243,660 B1
• Filed: 10/12/1999
• Issued: 06/05/2001
• Est. Priority Date: 10/12/1999
• Status: Expired due to Term

• Current Assignee: PNI Corporation (PNI Digital Media)
• Original Assignee: Precision Navigation, Inc.
• Inventors: Hsu, George, Sherer, Christine Annette, Oh, Chung-a Becky
• Primary Examiner(s): Shah, Kamini
• Assistant Examiner(s): Raymond, Edward
• Application Number:
  US09/417,254
• Time in Patent Office: 602 Days
• Field of Search: 702/159, 702/160, 335/01, 333/19, 333/22, 333/49, 333/55.R, 324/259, 324/260
• US Class Current: 702/160
• CPC Class Codes: G01C 17/30 Earth-inductor compasses
• CPC Class Codes: G01C 21/08 involving use of the magnetic field of the earth
• CPC Class Codes: G01C 21/16 by integrating acceleration or speed, i.e. inertial navigation
• CPC Class Codes: G01C 21/20 Instruments for performing navigational calculations G01C21/24, G01C21/26 take precedence

Abstract

A multi-function electronic compass incorporates multiple sensors in addition to magnetometers inputting sensed data to a microprocessor system which calculates a variety of results from the sensed data in addition to direction. Direction indicia and other results are output for a user on a display. Additional sensors include one or more of an inclinometer, an altimeter, an accelerometer, and a barometer. In one aspect the compass has a tilt-up lid with a sighting port and an adjacent mirror, and the microprocessor system displays directional indicia backwards so the reflected indicia in the mirror adjacent to the sighting port are directly readable by the user using the sighting port. In one model a laser beam is included as an aid in sighting.

Claims

1. A multi-function electronic compass, comprising:

a microprocessor system including electronic memory for managing functions of the electronic compass;

a magnetometer system coupled to the microprocessor for sensing the Earth'"'"'s magnetic field and providing input according to the direction of the Earth'"'"'s magnetic field relative to the orientation of the compass;

a display for providing output including directional indicia for a user of the compass; and

an accelerometer for sensing changes in acceleration of the compass;

wherein the microprocessor system uses accelerometer input and stored data to determine walking distance for a user of the compass, integrating the walking distance with direction input to determine changes in location for the user, and displays connected legs of a walking trip on the display, with the legs arranged in direction of travel and the length of each leg proportional to walking distance traveled in the direction of the leg.

2. The compass of claim 1 further comprising an altimeter providing altitude data to the microprocessor system, wherein the microprocessor system incorporates the altitude data in determining change in location for a user.

3. The compass of claim 1 further comprising a microphone input and a speech recognition system, wherein functions may be initiated by a user by voice command.

4. A multi-function electronic compass, comprising:

a microprocessor system including electronic memory for managing functions of the electronic compass;

a magnetometer system coupled to the microprocessor for sensing the Earth'"'"'s magnetic field and providing input according to the direction of the Earth'"'"'s magnetic field relative to the orientation of the compass;

a display for providing output including directional indicia for a user of the compass;

a tilt-up lid including a sighting port and an adjacent mirror; and

an input for the user to initiate a sighting mode;

wherein the user of the compass in sighting mode may incline the tilt up lid at a predefined angle and sight a distant target through the sighting port, and the microprocessor system in the sighting mode produces directional display in reverse, such that the directional display reflected in the mirror adjacent the sighting port is directly readable by the user while maintaining the sight of the distant target.

5. The compass of claim 4 further comprising a laser beam source producing a laser beam in the direction of the sighting port, such that the user may move the compass to place the laser beam on the distant object as an aid in sighting.

6. The compass of claim 5 further comprising an inclinometer providing input to the microprocessor system, and the microprocessor system uses the inclinometer input with direction in performing triangulation calculations.

7. The compass of claim 4 further comprising a prism in the body of the compass for reflecting display indicia into the mirror in the tilt-up lid.

8. A method for night navigation using an electronic compass, comprising steps of:

(a) setting a course direction and entering the course direction in the electronic compass;

(b) implementing a group of at least three LEDs on a face of the compass;

(c) determining a heading as a user moves at night with the compass;

(d) comparing the heading with the entered course direction;

(c) activating the LEDs selectively to indicate adherence to or deviation from course.

9. The method of claim 8 wherein three LEDs are used, a first being between a second and third LED, the first activated to indicate adherence to course, the second to indicate deviation to one side from course, and the third activated to indicate deviation to the opposite side from course.

10. The method of claim 9 wherein the second and third LEDs are blinked, the rate of blinking being proportional to magnitude of deviation from course.