But four problems exist in VNS, in which vehicle location precision and reliability and speediness, veracity and credibility of data communication especially stand out.

• 但目前车载导航系统存在的四大问题,其中车辆定位结果的精度及可靠性问题和信息通信的快速性、准确性及可靠性问题尤为突出。本文对这两方面进行了一些探讨与研究。