Article locator system

A method for locating an object, the method comprising:

• attaching a transceiver to the object, the transceiver comprising:
• a first receiver operable to receive a locator signal that contains a first address code;
• a first transmitter operable to wirelessly transmit a return signal;
• a first control unit operable to compare a second address code stored in a first memory unit with the address code contained in the locator signal, and activate the first transmitter to wirelessly transmit the return signal if the two codes are the same, wherein the first control unit is linked to the first memory unit, the first receiver, and the first transmitter;
• and
• a first timer linked to the first receiver and the first control unit, the first timer operable to activate the first receiver and first control unit at a specified time interval and for a specified time period;
• entering and storing the first address code in a locator unit, the locator unit comprising:
• a second memory unit operable to store the first address code;
• a user control operable to allow a user to input the first address code and select the first address code after it has been entered and stored;
• a second transmitter operable to wirelessly transmit the locator signal, wherein the locator signal includes the selected first address code;
• a second receiver operable to receive the return signal transmitted by the transceiver module;
• one or more antennas linked to the second receiver;
• a second control unit operable to calculate a relative direction of the transceiver module from the locator module, wherein the second control unit is linked to the second memory unit, the user control, the second transmitter, and the second receiver;
• selecting the first address stored in the locator unit;
• and
• activating the locator unit to wirelessly transmit the first address code to the transceiver, wherein if the transceiver receives the locator signal containing the first address code and verifies that the first address code matches the second address code stored in the transceiver, the return signal is sent from the transceiver to the locator module, and the locator module analyzes the return signal to determine the relative direction of the transceiver.

A system, comprising:

• a locator module comprising:
• a first radio frequency transmitter operable to transmit a first address code;
• a first receiver configured to receive a return signal transmitted by a second transmitter;
• an antenna array operably connectable to the first transmitter and the first receiver by a switch;
• and
• a first control unit operable to control the switch, the first control unit operable to determine the bearing of a transceiver module from the control unit;
• and
• the transceiver module comprising:
• a second receiver operable to receive the signal transmitted by the first transmitter;
• the second transmitter operable to transmit the return signal;
• a second control unit operable to compare the first address code transmitted by the locator module with an address code stored in the transceiver module and activate the second transmitter to transmit the return signal if the two codes match;
• and
• a timer operable to activate the second receiver and second control unit at a specified time interval and for a specified time period.

A transceiver comprising:

• means for receiving a first frequency band signal containing a transmitted address code;
• means for comparing the transmitted address code with a stored address code;
• means for transmitting a second frequency band loop-back tone return signal for a specified period of time when said transmitted address code matches said stored address code;
• and
• means for activating the means for receiving at desired intervals.

A method for range determination, comprising:

• providing an unmodulated carrier signal at a first frequency to a switch, the switch configured to commutate among antennas in a antenna array at a commutation frequency to transmit a first modulated signal modulated according to the commutation frequency;
• receiving the modulated signal in a tag receiver, an output of the tag receiver provided to a tag transmitter;
• transmitting a second modulated carrier from said tag transmitter, said second modulated carrier modulated according to said commutation frequency;
• receiving the second modulated carrier in a second receiver;
• adjusting said commutation frequency to minimize an output of the second receiver;
• and
• calculating a distance based on said commutation frequency.

A system, comprising:

• a locator module comprising:
• a first radio frequency transmitter operable to transmit a first address code;
• a first receiver configured to receive a return signal transmitted by a second transmitter;
• an antenna array operably connectable to the first transmitter and the first receiver by a switch;
• and
• a first control unit operable to control the switch, the first control unit operable to determine the distance of a transceiver module from the control unit;
• and
• the transceiver module comprising:
• a second receiver operable to receive the signal transmitted by the first transmitter;
• the second transmitter operable to wirelessly transmit the return signal;
• a second control unit operable to compare the first address code transmitted by the locator module with an address code stored in the transceiver module and activate the second transmitter to wirelessly transmit the return signal if the two codes match;
• and
• a timer operable to activate the second receiver and second control unit at a specified time interval and for a specified time period.

A system, comprising:

• a locator module comprising:
• a first radio frequency transmitter operable to transmit a first address code;
• a first receiver configured to receive a return signal transmitted by a second transmitter;
• an antenna array operably connectable to the first transmitter and the first receiver by a switch;
• and
• a first control unit operable to control the switch, the first control unit operable to determine the bearing of a transceiver module from the control unit and operable to detect the presence of multipath by examining a second harmonic of a commutation frequency of the antenna arrays and
• the transceiver module comprising:
• a second receiver operable to receive the signal transmitted by the first transmitter;
• the second transmitter operable to wirelessly transmit the return signal;
• a second control unit operable to compare the first address code transmitted by the locator module with an address code stored in the transceiver module and activate the second transmitter to wirelessly transmit the return signal if the two codes match.