TIDGET Emergency Location Sensor for Automobiles

The DOT has identified the need for an emergency location service as part of the IVHS program. GPS has been proposed as a method of providing location in support of this "Mayday" service. However, the expense, slow time-to-first-fix, and inability to compute a navigation fix except when four satellites are visible make conventional GPS receivers inappropriate for emergency location. NAVSYS has developed an alternative, low cost GPS sensor, the TIDGET, which is ideally suited for emergency location. This sensor was developed under the USAF contract for tracking radiosondes. Instead of tracking the GPS signals, the TIDGET sensor captures a brief "snapshot" of ray GPS sampled data and transmits this snapshot to the emergency dispatch center where the location of the motorist is computed. The central processing is aided by data from a map database when fewer than four satellites are in veiw of the sensor. The TIDGET requires no initialization or warm-up time since there is no processing of the data performed at the vehicle In large quantities, the TIDGET cost is less than $100 per unit, not including the cellular phone or other mobile communications link. Under this project, it is proposed to complete the TIDGET Mayday system architecture design and perform an initial in-vehicle demonstration of an emergency sensor. Anticipated Benefits: A reliable Mayday service will significantly increase highway safety, particularly in rural regions. The proposed TIDGET Mayday system architecture also permits value-added services to be provided to consumers through a public-private partnership. Commercial applications include AAA and tourist information services, stolen car recovery, and automatic vehicle location (AVL).