Electronic tether for portable objects

A method for monitoring an animal using electronic tether comprising:

• sending a signal from an animal worn monitoring module, wherein the signal comprises a first clock time T1 as measured by a first clock in the monitoring module at the time of transmission of the signal;
• receiving the signal from the animal worn monitoring module at an alert module;
• determining an arrival time T2 of the signal at the alert module as measured by a second clock in the alert module, wherein the first clock and the second clock are referenced to a common time T0;
• determining a signal propagation time indicative of the time for the signal to reach the alert module from the monitoring module, wherein the signal propagation time is equal to T2−T1;
• determining a separation distance between the animal worn monitoring module and the alert module based on the propagation time and a propagation speed of the signal;
• and
• issuing an alert when the separation distance exceeds a predetermined threshold.

A method for monitoring object location using an electronic tether comprising:

• sending a signal from a monitoring module, wherein the signal comprises a first clock time T1 as measured by a first clock in the monitoring module at the time of transmission of the signal;
• receiving the signal from the monitoring module at an alert module;
• determining an arrival time T2 of the signal at the alert module as measured by a second clock in the alert module, wherein the first clock and the second clock are referenced to a common time T0;
• determining a signal propagation time indicative of the time for the signal to reach the alert module from the monitoring module, wherein the signal propagation time is equal to T2−T1;
• determining a separation distance between the monitoring module and the alert module based on the propagation time and a propagation speed of the signal;
• and
• issuing an alert when the separation distance exceeds a predetermined threshold.

An electronic tether comprising:

• a monitoring module comprising a first clock, wherein the monitoring module is adapted to send a signal comprising a first clock time T1 as measured by the first clock at the time of transmission of the signal;
• and
• an alert module comprising a second clock, wherein the first clock and the second clock are referenced to a common time T0 and the alert module is adapted to:
• receive the signal from the monitoring module, wherein the signal is received at time T2;
• determine a signal propagation time indicative of the time for the signal to reach the alert module from the monitoring module, wherein the signal propagation time is equal to T2−T1;
• determine a separation distance between the monitoring module and the alert module based on the propagation time and a propagation speed of the signal;
• and
• issue an alert when the separation distance exceeds a predetermined threshold.

An anti-theft alert device comprising:

• a monitoring module comprising a portable transmitter adapted for transmitting an audio signal, wherein the monitoring module further comprises a first clock and the audio signal comprising a first clock time T1 as measured by the first clock at the time of transmission of the signal;
• and
• an alert module comprising a receiver wirelessly connected to the portable transmitter and a second clock, wherein the receiver is adapted to receive the signal from the transmitter, wherein the first clock and the second clock are referenced to a common time T0 and wherein the alert module is adapted to:
• receive the signal from the monitoring module, wherein the signal is received at time T2;
• determine a signal propagation time indicative of the time for the signal to reach the alert module from the monitoring module, wherein the signal propagation time is equal to T2−T1;
• determine a separation distance between the monitoring module and the alert module based on the propagation time and a propagation speed of the signal, and
• issue an alert when the separation distance exceeds a predetermined threshold.