| 摘要 |
PURPOSE:To decrease consumption power and to realize automatic driving by automatically turning on/off a transmitting/receiving power source in conformity with the time when it is possible to transmit/receive radio waves to and from a low-orbit satellite. CONSTITUTION:A signal from a satellite is detected by a receiving/processing part 2 via an antenna 1. The processing part 2 measures the receiving position based on the receiving signal, and at the same time calculates the predicted time to collect orbit data of the satellite on the basis of the orbit data of each satellite. The predicted time is sent and stored in a memory 4. Every time a time signal is received from the satellite, the processing part 2 sends a control signal to a real time clock 5, so that the time is corrected to a correct time. An automatic power source driving part 6 takes the predicted time for collecting of the orbit data stored in the memory 4 and the time data of the clock 5, and automatically turns on power sources of the processing part 2 and a transmitting/processing part 3 when both times agree. Subsequently, when the radio waves from the satellite are shut for a fixed time, the driving part 6 automatically shuts the power sources of the parts 2 and 3 in accordance with the control signal from the processing part 2. |
