在 這一篇 看到的
SONY Position Plus 感應器，短暫失去GPS信號，也能持續導航。所以是內建DR Sensor囉 ?
產品資訊在這裡，有關 SONY Position Plus 的說明
Unique Sony Position Plus technology ensures accurate, uninterrupted routing even when GPS signals are temporarily compromised. This can happen when a vehicle is travelling beneath a tunnel or bridge, between tall buildings or under trees with dense foliage that can obscure satellite signals. An acceleration sensor and pressure sensor interpret vehicle motion to assure more stable, reliable positioning information. Position Plus thus reduces the risk of incorrect position and route information being displayed – a major cause of driver frustration that can compromise road safety.所以真的是內建加速計和壓力計(高度?)。