METHOD FOR REDUCING IN-TRANSIT NAVIGATIONAL ERRORS

• US 20190310089A1
• Filed: 04/02/2019
• Published: 10/10/2019
• Est. Priority Date: 04/04/2018
• Status: Active Grant

• Current Assignee: Stidd Systems, Inc.
• Original Assignee: Stidd Systems, Inc.
• Inventors: Perry, Richard
• Granted Patent: US 11,054,262 B2
• Time in Patent Office: Days
• CPC Class Codes: G01C 21/1654 with electromagnetic compass
• CPC Class Codes: G01C 21/188 for accumulated errors, e.g. by coupling inertial systems with absolute positioning systems
• CPC Class Codes: G01C 25/005 initial alignment, calibration or starting-up of inertial devices

Abstract

A method for improving the accuracy of an inertial navigation system (INS) by performing a synchronization procedure to align the INS to a compass-derived initial heading comprises the steps of determining a heading of minimal error for the compass and defining that heading as the initial heading; orienting the INS to align with the so-defined initial heading; synchronizing the internal navigation system to that heading; and proceeding with navigation by use of the INS. The INS may be vehicle mounted or be contained in a portable navigation unit for swimmers or other users. The heading of minimal error may be determined by placing the compass within a multi-axis Helmholz coil system and monitoring compass readings and deviation errors as a function of actual compass positions.

Claims

1. A method for improving the accuracy of an inertial navigation system (INS) by performing a synchronization procedure to align the INS to a compass-derived initial heading, comprising the steps of:

a. determining a heading of minimal error for the compass and defining that heading as the initial heading;

b. orienting the INS to align with the so-defined initial heading;

c. synchronizing the internal navigation system to that heading; and

d. proceeding with navigation by use of the INS.

2. The method of claim 1 wherein the heading of minimal error is obtained from a display of error at one or more predetermined points as a function of indicated heading over a 360 degree circumference.

3. The method of claim 2 wherein the one or more points are used to create a graph of error over the 360 degree circumference.

4. The method of claim 1 wherein the INS is associated with a vehicle.

5. The method of claim 1 wherein the step of determining the heading of minimal error is performed by placing the compass within a multi-axis Helmholz coil system and monitoring the compass reading as a function of actual compass positions with respect to a known orientation of the magnetic field generated by the coil system and obtaining deviation values for various compass positions.