Localization using wireless signals

1. A method for localization of a target device within an environment, the method comprising the steps of:

providing a localization system within an environment, the localization system comprising a target device and a plurality of anchor devices, wherein the target device and one or more of the anchor devices are movable within the environment;

receiving, by each of the plurality of anchor devices, a plurality of received signal strength indication samples from another anchor device within the environment;

calibrating the localization system prior to each localization of the target device, wherein calibrating comprises: (i) determining a location for each of the plurality of anchor device using the plurality of received signal strength indication samples received by each of the plurality of anchor devices;

calibrating the localization system prior to each localization of the target device, wherein calibrating comprises: (i) obtaining, by each of the plurality of anchor devices, one or more received signal strength indication samples from every other of the plurality of anchor devices; (ii) converting, by each anchor device, the one or more received signal strength indication samples from every other anchor device into watts; and (iii) calculating calibration constants G and α for the anchor device utilizing the equation:

P w =αd −G

 where P w is mean power in watts for a received signal strength indication samples, d is a distance between a transmitting anchor device and a receiving anchor device, G is a path-loss exponent, and α is a scaling factor;

receiving, by the target device, a plurality of wireless signals transmitted from one or more of the plurality of calibrated anchor devices;

determining a received signal strength indication for at least some of the received plurality of wireless signals;

estimating, based on the determined received signal strength indications, a distance from the target device to each of the one or more of the plurality of calibrated anchor devices from which a wireless signal was received using the formula

ρ

=

(

α

P

_

⁢

W

)

-

G

 where ρ is a distance from the calibrated anchor device to the target device; and

estimating, based on the estimated distances, a location of the target device within the environment, wherein estimating a location of the target device comprises trilateration or multilateration;

wherein each of the target device and the plurality of anchor devices is configured to operate as a transmitter or as a receiver.

2. The method of claim 1 , wherein the wireless signal is a WiFi, ZigBee, Bluetooth signal, or other wireless protocols.

3. The method of claim 1 , wherein the method is repeated as the target device moves within the environment.

4. The method of claim 1 , wherein the target device comprises an application configured to perform said determining and estimating steps.

5. A system for localization of a target device within an environment, the system comprising:

a plurality of anchor devices located within the environment, each of the plurality of anchor devices configured to transmit a plurality of wireless signals to a target device, and wherein: (i) one or more of the plurality of anchor devices are movable within the environment; (ii) each of the plurality anchor devices is configured to transmit a plurality of signal strength indication samples to one or more of the other anchor devices within the environment; (iii) each of the plurality of anchor devices is configured to receive at least some of the transmitted plurality of signal strength indication samples; (iv) one or more of the plurality of anchor devices are configured to calibrate localization system prior to each localization of the target device, wherein calibrating comprises the steps of: (a) obtaining, by each of the plurality of anchor devices, one or more received signal strength indication samples from every other of the plurality of anchor devices; (b) converting, by each anchor device, the one or more received signal strength indication samples from every other anchor device into watts; and (c) calculating calibration constants G and α for the anchor device utilizing the equation:

P w =αd −G

 where P w is mean power in watts for a received signal strength indication samples, d is a distance between a transmitting anchor device and a receiving anchor device, G is a path-loss exponent, and α is a scaling factor;

a target device located within the environment, the target device configured to: (i) receive at least some of the plurality of transmitted wireless signals from the plurality of anchor devices, wherein the plurality of anchor devices are calibrated; (ii) determine a received signal strength indication for at least some of the received plurality of wireless signals; (iii) estimate, based on the determined received signal strength indications, a distance from the target device to each of the one or more anchor devices from which a wireless signal was received using the formula

ρ

=

(

α

P

_

⁢

W

)

-

G

 where ρ is a distance from the calibrated anchor device to the target device; and (iv) estimate, based on the estimated distances, a location of the target device within the environment, wherein the target device is configured to estimate the location of the target device using trilateration or multilateration;

wherein each of the target device and the plurality of anchor devices is configured to operate as a transmitter or as a receiver.