| 摘要 |
<p>PURPOSE:To prevent accuracy drop in ground speed due to noise by, under the condition where received power drops, utilizing directly and indirectly the original ground speed (those determined based on transmission frequency and reception frequency). CONSTITUTION:Based on the input signal from two comparison circuits 36 and 38, reception power is divided into three levels, high intermediate or low. In the case of high level, current temporal ground speed VPRV1 is taken in from a signal processing circuit 48, and stored in a RAM. In the case of low level, instead of taking in the current temporal ground speed VPRV1 from a signal processing circuit 48, previous ground speed VFNL1-1 is read out of the RAM, and it is stored in the RAM as current temporal ground speed VPRV1. In the case of intermediate level, after taking in the current temporal ground speed VPRV1 from a signal processing circuit 48, correction is made using a formula VPRV1+KK.VPRV1, and then it is stored in the RAM. In the formula, KK is a correction coefficient 0-1, that increases according to temporal ground speed (original ground speed).</p> |
