Because RF travels about 106 times faster than ultrasound, the listener can use the time difference of arrival
between the start of the RF message from a beacon and the corresponding ultrasonic pulse to directly infer its distance from the beacon.
Time difference of arrival
(TDOA) and frequency difference of arrival (FDOA) are precision emitter-location approaches, which were discussed in previous "EW 101" columns (see "Precision Emitter-Location Techniques," ]ED, December 2002, p.
Time Difference of Arrival
(TDOA) is the locating method pioneered by Cell-Loc, Inc.
In LTE, current standards support Observed Time Difference of Arrival
(OTDOA), an advanced cellular positioning technology that can augment A-GNSS and provide a more accurate location fix for indoor scenarios.
According to the company, the new solution forms the backbone of the TruePosition Uplink Time Difference of Arrival
(U-TDOA) Location Platform.
TruePosition's 144 patent relates to control channel Uplink Time Difference of Arrival
(U-TDOA) wireless location technology.
Like time difference of arrival
(TDOA), the frequency-difference measurement by two receivers does not define a location, it only defines a curve of possible positions -- i.
Lou Stilp, vice president and general manager of The Associated Group, invented and patented Time Difference of Arrival
(TDOA) in 1994.
The lawsuit had alleged undue delay in the standardization of Uplink Time Difference of Arrival
(U-TDOA) technology for LTE wireless networks in 3GPP.
According to the company, the system, which uses network-based Uplink Time Difference of Arrival
(U-TDOA), enables Plateau Wireless to satisfy the Phase II requirements of the Federal Communication Commission's Enhanced-911 mandate.
Two techniques are typically used for precision emitter location: time difference of arrival
(TDOA) and frequency difference of arrival (FDOA).