An apparatus and method for low frequency asset tracking includes a low
frequency transmitter tag associated with a cargo container or other high
value commodity, a plurality of receivers that detect low frequency
signals, and a microprocessor that uses algorithms and/or data pertaining
to the propagation characteristics of the signal to locate the position
of the container or high value commodity. The tag may include sensors to
monitor container properties or conditions, such as temperature, motion,
intrusion, RF fields, or other properties of interest. Sensor data may be
modulated on the low frequency transmitter signal.