| 摘要 |
<p>There are provided a mobile radio terminal capable of accurately detecting a moving speed without increasing power consumption or terminal cost and its speed detection method. Upon communication start, power of GPS reception system circuits (32, 33) is turned ON to detect the initial position of the mobile radio terminal (10). A rake receiver (24) and a synchronization detector (25) measure a Doppler shift amount from downstream signals of a known frequency received from a plurality of base stations. A CPU (41) calculates a relative speed for each of the base stations. A current moving speed of the mobile radio terminal (10) is obtained from the position of the base station, the initial position, and the relative speed. It should be noted that from the initial position and the current moving speed, the current position is calculated, which is used instead of the initial position in the next movement speed calculation, thus successively performing update. The initial position upon communication start may be obtained by the W-LAN, the RFID, a radio IC card, or user input information instead of using the GPS.</p> |
