Back to results
US 12,262,284 B2Granted
Wireless location system
AssigneeCenTrak, Inc.
InventorIsrael Amir
Life of this patent
Estimating the term…
Abstract
A system and methods for estimating the location of a mobile device are disclosed. In accordance with one embodiment, a mobile device receives, at a first time t1, a wireless electromagnetic signal, where the wireless electromagnetic signal comprises a first identifier that identifies a first beacon that transmitted the wireless electromagnetic signal. The mobile device receives, at a second time t2, t2>t1, an ultrasound signal lacking an identification of the source of the ultrasound signal. A time difference of arrival (TODA) t2−t1 is compared to a maximum TDOA. A location of the mobile device is estimated based on the TDOA only when the TDOA is less than or equal to the maximum TDOA.
Claims19
A method comprising:
- receiving by a mobile device, at a first time t1, a wireless electromagnetic signal, the wireless electromagnetic signal comprising a first identifier that identifies a first beacon that transmitted the wireless electromagnetic signal;
- receiving by the mobile device, at a second time t2, t2>t1, an ultrasound signal lacking an identification of the source of the ultrasound signal;
- comparing time difference of arrival (TDOA) t2−t1 to a maximum TDOA;
- and
- estimating a location of the mobile device, wherein the estimating is based on the TDOA only when the TDOA is less than or equal to the maximum TDOA;
- wherein the first beacon belongs to a plurality of beacons that transmit wireless electromagnetic signals and ultrasound signals, and wherein the maximum TDOA is based on the transmitted power of one or more of the ultrasound signals.
3 more elements
A method comprising:
- receiving by a mobile device, at a first time t1, a wireless electromagnetic signal, the wireless electromagnetic signal comprising a first identifier that identifies a first beacon that transmitted the wireless electromagnetic signal;
- receiving by the mobile device, at a second time t2, t2>t1, an ultrasound signal lacking an identification of the source of the ultrasound signal;
- comparing time difference of arrival (TODA TDOA) t2−t1 to a maximum TDOA;
- and
- estimating a location of the mobile device, wherein the estimating is based on the TDOA only when the TDOA is less than or equal to the maximum TDOA;
- wherein the first beacon belongs to a plurality of beacons that repeatedly transmit wireless electromagnetic signals and ultrasound signals in accordance with a period of T units of time divided into a plurality of time slots;
- and
- wherein each of the plurality of beacons is associated with a respective time slot;
- and
- wherein each of the plurality of beacons transmits during occurrences of the respective time slot;
- and
- wherein the number of beacons exceeds the number of time slots;
- and
- wherein a second beacon of the plurality of beacons and a third beacon of the plurality of beacons transmit during occurrences of a first time slot of the plurality of time slots;
- and
- wherein the second beacon transmits a second ultrasound signal during a first occurrence of the time slot, and wherein the third beacon transmits a third ultrasound signal during the first occurrence of the time slot;
- and
- wherein the first ultrasound signal and the third ultrasound signal have non-overlapping areas of coverage.
15 more elements
A method comprising:
- receiving, by a wireless receiver of a mobile device, at a first time t1, a first wireless electromagnetic signal, the first wireless electromagnetic signal comprising a first identifier that identifies a first beacon that transmitted the wireless electromagnetic signal;
- receiving, by a microphone of the mobile device, at a second time t2, t2>t1, an ultrasound signal lacking an identification of the source of the ultrasound signal;
- comparing time difference of arrival (TDOA) t2−t1 to a maximum TDOA;
- estimating a location of the mobile device, wherein the estimating is based on the TDOA only when the TDOA is less than or equal to the maximum TDOA;
- receiving by the wireless receiver, at a third time t3, a second wireless electromagnetic signal;
- and
- in response to the microphone not receiving any ultrasound signal within time interval [t3, t3+maximum TDOA], turning off the microphone.
4 more elements
Dependencies are inferred from the claim text.