Abstract

The purpose of the present invention is to increase the possibility of finding a person carrying a terminal device after a searching area has been specified, and to reduce the time until the person carrying the terminal device is found. A GPS signal processing unit (241) measures the current location of a terminal device (2) on the basis of a GPS signal, and stores terminal location information in a memory unit (232). A BS signal processing unit (242) transmits, to a base station via a first transmission unit (214), a signal including the terminal location information stored in the memory unit (232) and information indicating a specific destination. If information requesting the transmission of identification information of the present device is input from a searching device (1), a searching signal processing unit (243) transmits, to the searching device via a second transmission unit (217), a signal including the identification information of the present device and identification information of the searching device (1) which is the communication counterpart.

IPC Classes  ?

• G01S 5/12 - Position-fixing by co-ordinating two or more direction or position-line determinationsPosition-fixing by co-ordinating two or more distance determinations using radio waves by co-ordinating position lines of different shape, e.g. hyperbolic, circular, elliptical or radial
• G01S 1/68 - Marker, boundary, call-sign, or like beacons transmitting signals not carrying directional information
• G01S 13/76 - Systems using reradiation of radio waves, e.g. secondary radar systemsAnalogous systems wherein pulse-type signals are transmitted
• G01S 19/48 - Determining position by combining or switching between position solutions derived from the satellite radio beacon positioning system and position solutions derived from a further system
• H04B 1/034 - Portable transmitters
• H04M 1/00 - Substation equipment, e.g. for use by subscribers
• H04M 3/42 - Systems providing special services or facilities to subscribers

Abstract

　The purpose of the present invention is, relative to the prior art, to increase the likelihood of discovering a mountaineering accident victim or the like, and shortening the time to discovery. In standby mode, a beacon device (2), at each of first intervals, supplies electrical power to components and performs a reception process in a first period (321). A search device (1) having entered search mode repeatedly transmits call signals during a third period (312) longer than the first interval. The beacon device (2), upon receiving a call signal in the first period (321), transmits a response signal that includes identifying information about itself and the like, in a fourth period (322). Each time that a response signal is received, the search device (1) uses the response signal to estimate the distance and direction of the beacon device (2), and displays on a screen identifying information of the beacon device (2) and information pertaining to the distance and direction of the beacon device (2).

IPC Classes  ?

• G01S 5/12 - Position-fixing by co-ordinating two or more direction or position-line determinationsPosition-fixing by co-ordinating two or more distance determinations using radio waves by co-ordinating position lines of different shape, e.g. hyperbolic, circular, elliptical or radial
• G01S 1/68 - Marker, boundary, call-sign, or like beacons transmitting signals not carrying directional information
• G01S 13/76 - Systems using reradiation of radio waves, e.g. secondary radar systemsAnalogous systems wherein pulse-type signals are transmitted
• H04B 1/034 - Portable transmitters

Abstract

This invention provides communication devices that can increase the possibility of finding a person in distress in mountains or the like and further can shorten the time in which the person is found, as compared with the conventional devices. A sought device (2) in a waiting state supplies a power to each of a plurality of components thereof during a first time period (321) (for example, 3 ms) at first intervals, thereby performing a reception process. A seeking device (1) having got into a search state repetitively transmits a call signal during a third time period (312) that is longer than the first interval. When having received the call signal during the first time period (321), the sought device (2) transmits a response signal, which includes identification information and the like of the sought device, during a fourth time period (322). Upon each reception of the response signal, the seeking device (1) uses the response signal to estimate the distance and direction of the sought device (2), and causes the identification information of the sought device (2) and information related to the distance and direction of the sought device (2) to be displayed on a screen.

IPC Classes  ?

• H04B 1/034 - Portable transmitters
• H04W 4/02 - Services making use of location information
• H04W 64/00 - Locating users or terminals for network management purposes, e.g. mobility management