Wireless location system
AssigneeCell-Loc Inc.
InventorsMichel T. Fattouche, Richard W. Klukas, Andrew L. Borsodi, Mark Astridge, Gerard J. Lachapelle, Hatim Zaghloul
Life of this patent
Estimating the term…
Abstract
The position of a Wireless Transceiver (WT) is estimated using the Time Of Arrival (TOA) at several Monitoring Sites (MS) of the signal transmitted by the WT. Several sites are used to solve for the coordinates of the WT using hyperbolic trilateration. A time reference is used to synchronize the Monitoring Sites (MS). Super-Resolution (SR) techniques are applied to increase the resolution of the TOA estimate obtained via correlation of the received signal at each MS. SR techniques can improve the TOA resolution substantially.
Claims37
A wireless location system comprising:
- a plurality of monitoring stations (MS) and a central site (CS);
- each monitoring station including (a) a transceiver for monitoring a signal s(t) transmitted from a wireless transmitter and generating an estimate of the time of arrival (TOA) of the received signal relative to a time reference using an inverse transform whose resolution is greater than Rayleigh resolution and (b) a communication link to transmit the estimated TOA from the monitoring station to the central site;
- and
- the central site including (a) a difference unit that computes the time difference of arrival (TDOA) between each estimated TOA and a preselected TOA and (b) a position estimator which processes all TDOAs and generates an estimate of the position of the wireless transmitter.
A method of estimating the location of a wireless transmitter, the method comprising the steps of:
- monitoring a signal s(t) transmitted from the wireless transmitter at each one of a plurality of MSs;
- estimating the time of arrival (TOA) of the received signal relative to a time reference at each one of the plurality of MSs using an inverse transform whose resolution is greater than Rayleigh resolution;
- transmitting the estimated TOA from each one of the plurality of MSs to a central site (CS);
- computing the time difference of arrival (TDOA) between each estimated TOA and every other TOA at the CS;
- and
- processing all TDOAs to generate an estimate of the position of the transmitter.
Dependencies are inferred from the claim text.