×

Safety alert and locating system

  • US 4,813,025 A
  • Filed: 06/12/1987
  • Issued: 03/14/1989
  • Est. Priority Date: 06/12/1987
  • Status: Expired due to Fees
First Claim
Patent Images

1. A safety alert and locating system comprising,means for transmitting first and second coded interrogation signals from a central location, each of said first and second interrogation signals containing at least one address code, said first signal being transmitted through a first transmission medium and said second signal being transmitted through a second, different transmission medium,one or more individual means adapted to receive said coded signals, each of said individual means being located at a distance from and at an angle to said central location and being responsive to its own address code contained in said first and second signals,each of said individual means being adapted to transmit a response signal upon receipt of at least one of said first and second signals addressed to it, the response signal being transmitted through the transmission medium through which the signal was received,means at said central location for receiving the signal transmitted by said individual means, andlocation determining means at the central location for determining from the received signal the distance and angle of said individual means relative to said central location.

View all claims
  • 2 Assignments
Timeline View
Assignment View
    ×
    ×