An object locator device is disclosed for use in conjunction with both a
GPS satellite system and a two-way communication satellite. The object
locating system includes a mobile unit physically connected to the object
to be located. The mobile unit includes a satellite communication
transceiver capable of receiving and transmitting encoded signals. A
decoder is associated with the satellite communication transceiver for
decoding a unique signal associated with that mobile unit and for
generating an activation signal upon receipt of the unique signal. The
mobile unit further includes a GPS receiver which is activated in response
to the receipt of the unique signal so that the GPS receiver generates a
position signal representative of the position of the mobile unit. The
output signal from the GPS receiver is connected as an input signal to the
satellite communication transceiver such that the satellite communication
transceiver transmits the.position signal to a base station on the
communication satellite. The base station physically separated from the
remote unit is operable to both transmit the unique signal to the
communication satellite in order to activate the mobile unit as well as
for receiving the position signal from the communication satellite
following activation. The base station creates a display representative of
the location of the mobile unit. Preferably, this display signal is
transmitted via a telephone line and modem to a computer which generates
the display on a computer monitor. Energy conservation algorithms
including periodic activation of the satellite communication transceiver
as well as activation of the satellite communication transceiver only when
the position of the mobile unit has changed more than a threshold amount
between periodic signals is disclosed.