Wi-Fi position fix

US8994590B2 · kind B2 · utility

Assignee

• CAMBRIDGE SILICON RADIO LIMITED · GB

Inventors

• Murray Robert Jarvis · Stapleford, GB
• Ben Tarlow · Gainsborough, GB

Key dates

• Filing date: Sep 30, 2011
• Grant date: Mar 31, 2015
• Expiry date: Oct 3, 2033

Classification

• Technology area (CPC G): Physics
• CPC primary: G01S5/14
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A method of forming an estimate of the two-dimensional position of a radio receiver relative to a plurality of radio transmitters each having an associated position estimate and a position uncertainty expressible as an uncertainty ellipse having major and minor axes, the method comprising using the uncertainty vectors describing the uncertainty ellipses of the radio transmitters in a predetermined coordinate system to define a new compound coordinate basis, and forming an estimate of the two-dimensional position of the radio receiver in the compound coordinate basis by projecting the major and minor axes of each uncertainty ellipse onto the new compound coordinate basis and calculating the position of the radio receiver by means of a weighted centroid that uses weighting values calculated in the new compound coordinate basis and position estimates of the plurality of the radio transmitters expressed in the compound coordinate basis.