System and method for locating a target using RFID

A method, comprises the steps of:

• determining a value of a point P1 from position information received by a transceiver corresponding to a location of a transponder disposed on a target;
• prompting a user to move said transceiver to a point P2 relative to a location of the target;
• determining a value of a point P2 from position information received by said transceiver corresponding to a location of said transponder;
• prompting said user to move said transceiver to a point P3 relative to a location of the target;
• determining a value of a point P3 from position information received by said transceiver corresponding to a location of said transponder;
• and
• finding the location of the target by virtual triangulation based on the values for said points P1, P2 and P3.

A portable device for tracking a target, comprising:

• processor for determining position information of the target, memory operably connected to said processor, said memory being configured to store a plurality of sequences of instructions, said plurality of sequences of instructions including sequences of instructions which, when executed by said processor, cause said processor to perform the steps of:
• determining a value of a point P1 from position information received by a transceiver corresponding to a location of a transponder disposed on a target;
• prompting said user to move said transceiver to a point P2 relative to a location of the target;
• determining a value of a point P2 from position information received by said transceiver corresponding to a location of said transponder;
• prompting said user to move said transceiver to a point P3 relative to a location of the target;
• determining a value of a point P3 from position information received by said transceiver corresponding to a location of said transponder;
• and
• finding the location of the target by virtual triangulation in accordance with each of said values for said points P1, P2 and P3 of position information received by said transceiver.

An integrated circuit for a wireless system for locating and tracking a subject or object, comprising:

• a receiver;
• a transmitter;
• a microprocessor having a common clock as a source of synchronization;
• whereby said receiver and transmitter together define an active transponder and the integrated circuit is preferably a monolithic single die integrated circuit including said receiver, said transmitter, and said microprocessor;
• said transponder supplies predetermined ranging signals to a data processor portion of said microprocessor, said transponder includes an encoder for encoding data for transmission by said transmitter, and said a receiver includes a decoder circuit for receiving and decoding signals received from said antennae, and said a data processor for determining interval and position information, said data processor comprising a digital signal processor (DSP), a voltage stabilizer, and a battery supervisor;
• and
• an antenna for propagating said ranging said signal.

A method of a dynamic, mobile network for tracking and locating a plurality of monitoring units and targets T, comprising:

• tracking a primary target T with a primary monitoring unit having a predetermined range;
• determining when said primary target T moves out of said predetermined range;
• sending a ranging signal to at least one secondary monitoring unit within said predetermined range;
• receiving a reply ranging signal from at least one of said secondary monitoring unit;
• sending a request for a list of identified targets T to said secondary monitoring unit within a range of said secondary monitoring unit;
• receiving said list of identified targets T from said secondary monitoring unit;
• comparing said list of identified targets T to said primary target T;
• matching said primary target T to one of said list of identified targets T from said secondary monitoring unit;
• and
• determining the location of the primary target from position information provided by said secondary monitoring unit.

A method for finding a target, comprising the steps of:

• determining a point P1 by having a user make an input to a monitoring unit;
• transmitting a ranging signal from said monitoring unit;
• receiving a reply ranging signal from a slave unit located on a subject or on an object at a point T, where said point T is located out of a range of said master unit;
• entering a homing mode on said monitoring unit;
• prompting said user to select a direction and having said user move in said direction along a path “Delta (1)” in a direction towards a point P2;
• actuating a step button on said monitoring unit to input once for each step taken by said user to generate reference points for a virtual triangulation calculation;
• prompting said user through said master unit to stop data input of said step button when said user reaches said point P2 determining using a processor of said monitoring unit whether the distance between subsequent points Delta (n) is equal or greater than (4-5)*E such that a value of said path Delta (1) is sufficiently large to minimize a position ambiguity of said point T.

A method for finding a target, comprising the steps of:

• determining a point P1 by having a user make an input to a monitoring unit;
• transmitting a ranging signal from said monitoring unit;
• receiving a reply ranging signal from at least three stationary slave units located on subjects or on objects at a points T1, T2 and T3 within a predetermined range of said monitoring unit,
• whereby each of said points T1, T2 and T3 form a set of virtual coordinates relative to said point P1;
• and
• determining a location of said monitoring unit relative to said slave units using triangulation of points T1, T2 and T3 and said virtual coordinates relative to said point P1.

A method for finding a target, comprising the steps of:

• transmitting a ranging signal from a searching monitor unit MS;
• receiving a reply ranging signal from at least three stationary slave units located on subjects or on objects at a points P1, P2 and P3 within a predetermined range of said searching monitor unit MS,
• whereby each of said points P1, P2 and P3 form a set of virtual coordinates relative to said point P1;
• determining said points P1 and P2 relative to said searching monitor unit MS having virtual coordinates X and Y using a processor of said searching monitor unit MS;
• determining a location of a mobile slave unit disposed on a subject forming a tracked target T, said target T having virtual coordinates are Ty and Tx;
• determining a location of said searching monitor unit MS relative to said tracked target T using said virtual coordinates formed by said stationary slave units and said virtual coordinates are MSxy and Smy for said searching monitor unit MS.