US 5,612,703 A · position determination in an integrated cellular communications system

Abstract

A cellular communications system is provided having both surface and satellite nodes which are fully integrated for providing service over large areas. Position means are included for determining the position of a selected user unit within the cells by providing a timing signal to the selected user unit from at least one node, providing a timing response signal from the selected user unit in response to each timing signal, receiving the timing response signal by at least one node, measuring the response time of the user unit to the timing signal based on receipt of the timing response signal, and determining the position of the user unit based on the round trip time of transmission of the timing signal and receipt of the timing response signal. Preferably, the invention provides position determination in a cellular communications system using code division multiple access (CDMA) employing forward error correction coding (FECC) and spread spectrum waveforms.

Claims2

Dependent claims

A cellular communications system comprising:

at least one node positioned so to establish a set of cells, each node including means for transmitting and receiving different predetermined sets of code division multiple access coded, digitally modulated spread spectrum waveforms;
a plurality of user units within the cells, each user unit including means for communicating with at least one of said nodes and being operatively responsive to a predetermined one of the sets of code division multiple access coded waveforms to thereby establish selective communication with at least one of said nodes;
and
position determination means for determining the position of a selected user unit by providing a timing signal carried by one of the sets of code division multiple access coded waveforms to the user unit from one or more nodes, providing a timing response signal carried by one of the sets of code division multiple access coded waveforms from the selected user unit in response to each timing signal, receiving the timing response signal by at least one node, measuring the response time of the user unit to each timing signal, and determining the position of the user unit based on such measurements.

1 more element

Dependencies are inferred from the claim text.

position determination in an integrated cellular communications system

Life of this patent

position determination in an integrated cellular communications system

Life of this patent

Abstract

Claims2