Abstract:
A communication service equipment and a search and rescue terminal device for vessels that are set on board to provide radio communication service including at least one radio signal transmission and reception units, a modulation and demodulation unit, a location information receiving unit, a plurality of frequency conversion unit, signal processing units each connected to the frequency conversion unit, a main control unit, and control the signal processing unit.
Abstract:
A bidirectional positioning system is disclosed. The system having a plurality of mobile stations radiating ultrasonic signals to notice a physical location of correspondence mobile station and to request additional information, the bidirectional positioning system, including: a plurality of ultrasonic transceivers for receiving the ultrasonic signal from the plurality of mobile stations and measuring a receiving time of the ultrasonic signal with a correspondence mobile station; and a positioning server for computing physical locations of the plurality of mobile stations by collecting three or more receiving times of correspondence mobile station from the plurality of ultrasonic transceivers, storing the computed physical locations of the plurality of mobile stations in a database, generating a radio frequency (RF) information signal to have information about computed physical location of the mobile stations by receiving the ultrasonic signal from the plurality of ultrasonic transceivers and transmitting the RF information signal to the mobile stations.
Abstract:
A communication service equipment and a search and rescue terminal device for vessels that are set on board to provide radio communication service including at least one radio signal transmission and reception units, a modulation and demodulation unit, a location information receiving unit, a plurality of frequency conversion unit, signal processing units each connected to the frequency conversion unit, a main control unit, and control the signal processing unit.