MULTIPATH COMPENSATION WITHIN GEOLOCATION OF MOBILE DEVICES

• US 20120309415A1
• Filed: 07/21/2011
• Published: 12/06/2012
• Est. Priority Date: 07/21/2010
• Status: Abandoned Application

• Current Assignee: Digimarc Corporation
• Original Assignee: ZuluTime LLC
• Inventors: Rhoads, Geoffrey B.
• Application Number:
  US13/187,723
• Publication Number:
  US 20120309415A1
• Time in Patent Office: Days
• US Class Current: 455/456.1
• CPC Class Codes: G01S 5/0218 Multipath in signal reception
• CPC Class Codes: G01S 5/0273 using multipath or indirect path propagation signals in position determination
• CPC Class Codes: G01S 5/0289 of multiple transceivers, e.g. in ad hoc networks

Abstract

A location of a mobile device within a network is determined. The network includes a plurality of fixed nodes. A method includes receiving, at the plurality of fixed nodes, receive messages transmitted from the mobile communication device. Each of the plurality of fixed nodes generates a receive count stamp for each receive message corresponding to a local counter value at the receipt of the receive message. At each of the plurality of fixed nodes, the method includes processing the receive count stamps to calculate a set of pseudo-ranges between the respective fixed node and the mobile device, and measuring multipath delay included within the set of pseudo-ranges. Based on the measurement, the multipath delay is removed from the set of pseudo-ranges to determine a range estimate between the mobile device and each of the fixed nodes. Based on the range estimates, a location of the mobile device is calculated.

Claims

1. A method of determining a location of a mobile device in a network, the network including a plurality of fixed nodes, the method comprising:

receiving, at the plurality of fixed nodes, receive messages transmitted from the mobile communication device, wherein each of the plurality of fixed nodes generates a receive count stamp for each receive message corresponding to a local counter value at the receipt of the receive message;

at each of the plurality of fixed nodes, processing the receive count stamps to calculate a set of pseudo-ranges between the respective fixed node and the mobile device;

measuring multipath delay included within the set of pseudo-ranges;

based on the measurement, removing the multipath delay from the set of pseudo-ranges to determine a range estimate between the mobile device and each of the fixed nodes; and

based on the range estimates, calculating a location of the mobile device.

2. The method of claim 1, further comprising sending and receiving messages between the plurality of fixed nodes, wherein each of the fixed nodes generates local receive count stamps based on the messages received from the other fixed nodes.

3. A method for multipath mitigation and evaluation within a network comprising a plurality of nodes, the method comprising:

receiving, at a plurality of first nodes, receive messages transmitted from a second node, wherein each of the plurality of first nodes generates a receive count stamp for each receive message corresponding to a local counter value at the receipt of the receive message; and

processing the receive count stamps to determine range errors in at least one of an x-axis direction, a y-axis direction, and a z-axis direction with respect to a distance between at least one of the first nodes and the second node.