| 摘要 |
PURPOSE:To enable acquisition of a ground-wave signal even in a region wherein the conditions of reception are bad, by operating and determining a ground-wave signal acquisition timing of one station on the basis of a ground-wave signal tracking timing of another station and on an information on a current position. CONSTITUTION:When a ground-wave signal, which is decided to be the gound-wave signal on the basis of a wave of a third cycle or the like from a slave station, etc. where the conditions of reception are good, is tracked by a sampling circuit 4, a tracking timing is stored in RAM71 of a microcomputer 7 formed of CPU70, ROM72, RAM71, etc. Then, when an information on a current position is given by NNSS11 or an input key 9, the computer 7 is interrupted and an acquisition timing of a master station or another slave station is computed through operation on the basis of the information on the current position and of a cycle of a set scanning chain and a time of reception and acquisition of a ground wave, which are memorized in RAM71. According to the result of this operation, a real time counter 8, a strobe signal generating circuit 5 and the circuit 4 are controlled, thereby the ground-wave signal is acquired even in a region wherein the conditions of reception are bad, and thus false tracking of an air- wave signal, or the like, is prevented. |
