Method of factorizing pseudodistance time of week in an assisted GNSS context

• US 20050174285A1
• Filed: 01/27/2005
• Published: 08/11/2005
• Est. Priority Date: 01/28/2004
• Status: Active Grant

• Current Assignee: Sound View Innovations, LLC (Sound View Innovation Holdings, LLC)
• Original Assignee: Alcatel SA (Nokia Corporation)
• Inventors: Monnerat, Michel
• Granted Patent: US 7,312,748 B2
• Time in Patent Office: Days
• US Class Current: 342/357.460
• CPC Class Codes: G01S 19/09 providing processing capability normally carried out by the receiver
• CPC Class Codes: G01S 19/252 Employing an initial estimate of location in generating assistance data

Abstract

A method is disclosed of calculating the position of a mobile device in which an assistance data server provides aid with solving the point of the mobile device and the mobile device communicates with the server via a cellular network and receives positioning signals from a satellite positioning system using a spread spectrum access technique. The method comprises the following steps: following reception of the positioning signals, the device sends the server a set of spreading code phases corresponding to the satellites acquired, the code phases having a single time of week indication corresponding to the transmission time of one of the code phases; the server deduces from the information the transmission times corresponding to the code phases and the pseudodistances; and the server solves the point.

Claims

1. A method of calculating the position (or point) of a mobile device, said method employing an assistance data server for providing aid with solving the point of said mobile device and said mobile device comprising means for communicating with the server via a cellular mobile telephone network and means for receiving positioning signals from a satellite positioning system using a spread spectrum access technique, said method comprising the following steps:

following reception of said positioning signals, the device sends said server a set of spreading code phases corresponding to the satellites acquired, said code phases having a single time of week indication corresponding to the transmission time of one of the code phases,

said server deduces from said information the transmission times corresponding to said code phases and said pseudodistances, and

said server solves said point.

2. A method of calculating the position (or point) of a mobile device, said method employing an assistance data server for providing aid with solving the point of said mobile device and said mobile device comprising means for communicating with the server via a cellular mobile telephone network and means for receiving positioning signals from a satellite positioning system using a spread spectrum access technique, said method comprising the following steps:

said mobile device sends said server a set of code phases corresponding to the acquired satellites, said code phases being measured relative to the start of millisecond slices maintained by a local clock, said code phases having a time of week relative to a transmission time,

said server deduces said pseudodistances from said code phases and the associated transmission time, and

said server calculates the position of said mobile device.

3. A method of calculating the position (or point) of a mobile device, said device comprising means for receiving positioning signals coming from a satellite positioning system using a spread spectrum access technique, in which method, to avoid reading the transmission TOW T_e of said positioning signals, a non-linear technique is used to minimize the following function, in which Xu, Yu, Zu represent the position of the mobile device, Δ

T represents the clock error in the pseudodistance measurement, and T_e represents the transmission TOW of the positioning signals;

4. The method claimed in claim 3 wherein said step of minimizing said function f is based symmetrically on said reception TOW T_r of said positioning signals instead of said transmission TOW T_e.

5. The method claimed in claim 3 wherein said step of minimizing said function f is carried out by calculation means of said mobile device.

6. The method claimed in claim 3 wherein, said method using an assistance data server for providing aid with solving the point of the mobile device and said mobile device comprising means for communicating with the server via a cellular mobile telephone network, said minimization step of said method is executed by calculation means of said server.

7. A method of calculating the position (or point) of a mobile device, said device comprising means for receiving positioning signals from a satellite positioning system using a spread spectrum access technique, in which method, to avoid reading the transmission TOW T_e in the positioning signals, the position of the user is solved for a plurality of hypotheses as to the transmission TOW T_e and finally retaining only the position obtained from the hypothesis as to the transmission TOW T_e that minimizes a user position estimation residue.