The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 27, 2003
Filed:
Jul. 24, 2001
Bishnu P. Phuyal, DesPlaines, IL (US);
Nicholas E. Smith, Birmingham, GB;
Navigation Technologies Corporation, Chicago, IL (US);
Abstract
A method for calculating a distance between a first point and a second point using linear interpolation is provided. The first point and the second point are located between a first latitude and a second latitude. An interpolated prime vertical radius of curvature value for a point between the first point and the second point is calculated based on a first prime vertical radius of curvature value for the first latitude and a second prime vertical radius of curvature value for the second latitude. An interpolated meridian radius of curvature value for the point between the first point and the second point is calculated based on a first meridian radius of curvature value for the first latitude and a second meridian radius of curvature value for the second latitude. An interpolated cosine value for the point between the first point and the second point is calculated based on a value representing a cosine of the first latitude and a value representing a cosine of the second latitude. The distance between the first point and the second point is then calculated based on the interpolated prime vertical radius of curvature value, the interpolated meridian radius of curvature value, and the interpolated cosine value. The use of interpolated prime vertical radius of curvature, meridian radius of curvature, and cosine avoids use of non-linear function evaluation. As a result, the process is efficient and the calculated distances are sufficiently accurate.