Position enhanced communication system including system for embedding CDMA navigation beacons under the communications signals of a wireless communication system

• US 6,850,734 B1
• Filed: 11/21/2000
• Issued: 02/01/2005
• Est. Priority Date: 12/23/1994
• Status: Expired due to Fees

• Current Assignee: ITT Manufacturing Enterprises, Inc. (ITT, Inc.)
• Original Assignee: ITT Manufacturing Enterprises, Inc. (ITT, Inc.)
• Inventors: Bruno, Ronald, Schuchman, Leonard, Engelbrecht, Lloyd
• Primary Examiner(s): Corsaro, Nick
• Assistant Examiner(s): Lee, John J
• Application Number:
  US09/716,370
• Time in Patent Office: 1,533 Days
• Field of Search: 455/423, 455/63, 455/522, 455/63.2, 455/456.2, 455/67.3, 455/524, 455/561, 455/112, 455/562.1, 455/63.1, 455/69, 455/67.11, 455/67.13, 455/456.1, 455/456.5, 455/68, 455/517, 455/70, 455/41.1, 455/41.2, 455/296, 370/335, 340/988, 340/991, 340/992, 340/989, 375/130, 375/139
• US Class Current: 455/63.1
• CPC Class Codes: G01C 21/206 specially adapted for indoor navigation
• CPC Class Codes: G01S 1/68 Marker, boundary, call-sign, or like beacons transmitting signals not carrying directional information
• CPC Class Codes: G01S 19/21 Interference related issues ; Issues related to cross-correlation, spoofing or other methods of denial of service
• CPC Class Codes: G01S 19/46 the supplementary measurement being of a radio-wave signal type
• CPC Class Codes: H04B 2201/70715 with application-specific features
• CPC Class Codes: H04W 48/08 Access restriction or access information delivery, e.g. discovery data delivery signalling during connection H04W76/00
• CPC Class Codes: H04W 72/00 Local resource management
• CPC Class Codes: H04W 84/042 Public Land Mobile systems, e.g. cellular systems
• CPC Class Codes: H04W 88/08 Access point devices

Abstract

A cellular telephone system having three or more cell sites with each cell site having a source of cellular communication signals and an RF transmitter and antenna for broadcasting the cellular communication signals. A direct sequence spread spectrum waveform carrying navigation signals is embedded in the cellular communication signals, including controlling the signal strength of the navigation signals so that the combined energy of the navigation signals from all cell sites at any location is at least a predetermined energy level below the energy level of the cellular communication signals. Each cell site includes timing for timing the operation of a GPS receiver. An RF signpost system comprising a plurality of low powered RF broadcast stations, one each at a plurality of scattered geographic locations, each low powered RF broadcast station broadcasting a direct sequence spread spectrum digital RF waveform and means to modulate the digital RF waveform with location information identifying the geographic locations, respectively.

Claims

1. A method of avoiding near-far interference in a cellular array of wireless base station navigation signal beacons, comprising:

each said wireless base station broadcasting a signal having selected navigation signals embedded therein,

using multiple frequencies and time-division multiplexing, and

coordinating the use of said multiple frequencies and said time division multiplexing among said wireless base station navigation signal beacons to assure avoidance of said near-far interference.