System using leo satellites for centimeter-level navigation

US6373432B1 · kind B1 · utility

Assignee

• The Board of Trustees of the Leland Stanford Junior University · US

Inventors

• Matthew Rabinowitz · San Francisco, US
• Bradford W. Parkinson · Los Altos, US
• Clark E. Cohen · Washington, US
• David G. Lawrence · Santa Clara, US

Key dates

• Filing date: Jul 25, 2000
• Grant date: Apr 16, 2002
• Expiry date: Jul 25, 2020

Classification

• Technology area (CPC G): Physics
• CPC primary: G01S19/05
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

Disclosed herein is a system for rapidly resolving position with centimeter-level accuracy for a mobile or stationary receiver [4]. This is achieved by estimating a set of parameters that are related to the integer cycle ambiguities which arise in tracking the carrier phase of satellite downlinks [5,6]. In the preferred embodiment, the technique involves a navigation receiver [4] simultaneously tracking transmissions [6] from Low Earth Orbit Satellites (LEOS) [2] together with transmissions [5] from GPS navigation satellites [1]. The rapid change in the line-of-sight vectors from the receiver [4] to the LEO signal sources [2], due to the orbital motion of the LEOS, enables the resolution with integrity of the integer cycle ambiguities of the GPS signals [5] as well as parameters related to the integer cycle ambiguity on the LEOS signals [6]. These parameters, once identified, enable real-time centimeter-level positioning of the receiver [4]. In order to achieve high-precision position estimates without the use of specialized electronics such as atomic clocks, the technique accounts for instabilities in the crystal oscillators driving the satellite transmitters, as well as those in …