Abstract: A position detection system and a portable terminal are disclosed. The portable terminal carries out communication with a server in the first position detection session and thereby acquires the GPS assist information and the base station position information from the server. Using the GPS assist information thus acquired, the portable terminal transmits the GPS signal received from a GPS satellite to the server, and receives the position information of the portable terminal calculated by the server. In the second and subsequent sessions of position detection, the portable terminal neither establishes communication with the server nor receives the GPS signal, but makes calculations for position detection on its own using the result of measuring the radio wave propagation time from nearby base stations, the position information of the portable terminal obtained in the preceding session and the base station position information.

Abstract: A portable terminal device including GPS correctly detects a position thereof by preventing an error due to a state of an environment thereof. In a portable telephone including a GPS receiver capable of receiving a GPS signal according to GPS assist information sent from a reference GPS receiver server continuously receiving GPS signals from GPS satellites, a result of acquisition of each GPS signal received by the telephone using the GPS assist information and the like is evaluated to produce GPS information to be reported to the server.

Abstract: An improved, compact, lightweight handy-phone provided with a built-in directional planar antenna is provided. The planar antenna is mounted on a portion of a high-frequency printed wiring board, and a shielding case covers the high-frequency printed wiring board with a surface of the portion exposed. A maximum linear size of the shielding case in the direction of main polarization of the planar antenna is nearly equal to half the wavelength of an electromagnetic wave to be radiated by the planar antenna.

Abstract: A coaxial resonant slot antenna having a novel structure is provided to further reduce the dimensions of radio terminals incorporating such an antenna. Also provided are a novel method of fabricating such a coaxial resonant slot antenna and a radio terminal having a novel structure using such a coaxial resonant slot antenna. An entire strip conductor is arranged inside a flat conductive cubic such that the strip conductor is insulated from the conductive cubic. A connection point between the strip conductor and a radio frequency transmission line is provided at a position about 1/4 of wavelength away from one end of the strip conductor. A slot is shaped into a narrow rectangle, a generally upside-down "U", or a generally upside-down "U" having another slot on each end. It is desired that the center slot crosses the strip conductor along the length thereof and in the height direction thereof, the distance between the ends being equivalent to about 1/2 of wavelength used.