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

  • US 5,604,765 A
  • Filed: 12/23/1994
  • Issued: 02/18/1997
  • Est. Priority Date: 12/23/1994
  • Status: Expired due to Term
First Claim
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1. In 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 said cellular communication signals, the improvement comprising:

  • means for embedding a direct sequence spread spectrum waveform carrying navigation signals in said cellular communication signals, including means for controlling the signal strength of said navigation signals so that the combined energy of said navigation signals from all said cell sites at any location is at least a predetermined energy level below the energy level of said cellular communication signals.

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