Personnel monitoring and locating system

A system for monitoring a plurality of underground miners within a mine, said system comprising:

• transmitting means positioned within said mine and providing an interrogation output;
• a plurality of transponder means each of which is associated with and constrained to movement with a different one of said underground miners, with each of said transponder means, responsive to receipt of said interrogation output from said transmitting means, providing a reply output with said reply output from each of said transponder means occurring at different time intervals with respect to one another, said miners being equipped with lighting means including a power cord, and wherein said transponder means are connected with said power cord whereby said power cord provides a transmitting and receiving antenna for said transponder means;
• receiving means at said predetermined area for receiving said reply outputs from said transponder means;
• and
• decoding means connected with said transmitting means and said receiving means for decoding said reply outputs received from said transponder means and, responsive thereto, providing an indication of said movable objects associated with said replying transponder means.

A system for monitoring a plurality of movable objects within a preselected area, said system comprising:

• a plurality of remote terminals at said preselected area;
• a plurality of transceiver units each of which is connected with a different one of said remote terminals with each of said transceiver units providing an interrogation output at predetermined times and for receiving reply outputs responsive thereto;
• computer means;
• communication link means connecting said remote terminals with said computer means;
• a plurality of transponders each of which is associated with a different one of said objects to be monitored, each of said transponders having means for receiving said interrogation output from said transceiver units and responsive thereto providing reply outputs with the reply output from each of said transponders being delayed by different predetermined time intervals so that all reply outputs from said transponders are timewise spaced with respect to one another;
• and
• signal processing means for providing an output indicative of the particular transponder from which a reply output was received to thereby enable monitoring of the objects associated with said transponders.

A system for monitoring underground miners, said system comprising:

• a plurality of remote terminals within a mine;
• a plurality of transceiver units each of which is connected with a different one of said remote terminals with each of said transceiver units providing an interrogation output at predetermined times;
• a plurality of first "parallel-to-serial" communication links each of which is connected with a different one of said remote terminals;
• modem means connected with said first parallel-to-serial communication links;
• a second parallel-to-serial communication link connected with said modem means;
• computer means connected with said second parallel-to-serial communication link;
• a plurality of transponders each of which is carried by a different miner to be monitored, with each of said transponders including means for receiving said interrogation output from said transceiver units and responsive thereto providing reply outputs with the reply output from each of said transponders being delayed by different predetermined time intervals so that all reply outputs from said transponders are timewise spaced with respect to one another;
• and
• signal processing means connected with said transceiver means for providing an output indicative of the particular transponder from which a reply output was received to thereby enable monitoring of transponder equipped miners.