关于P3D磁航向

QyRemember

截获盲降后磁航向总会在正确数值基础上在上调一，请问是什么原因呢？

boss6tg

There may be slight differences between the course information portrayed on navigational charts and a GPS navigation display when flying authorized GPS instrument procedures or along an airway.  All magnetic tracks defined by any conventional navigation aids are determined by the application of the station magnetic variation.  In contrast, GPS RNAV systems may use an algorithm, which applies the local magnetic variation and may produce small differences in the displayed course.  However, both methods of navigation should produce the same desired ground track when using approved, IFR navigation system.  Should significant differences between the approach chart and the GPS avionics’ application of the navigation database arise, the published approach chart, supplemented by NOTAMs, holds precedence.
我的理解是导航计算机把本地磁差算进去了。