A simple inertial or Doppler navigation has a common defect that position errors are always increasing with flight time or distance, therefore an external reference system is necessary.是什么意思_A simple inertial or Doppler navigation has a common defect that position errors are always increasing with flight time or distance, therefore an external reference system is necessary.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句