The proliferation of GPS units in our life has greatly changed how people find their ways in the real world. However, overreliance on step-by-step route directions from these automated navigation systems may result in less consciously building spatial knowledge of the environment, which is critical to wayfinding. Also, GPS devices may divert people's attention from objects in the physical world to virtual representations on screen, and make people less engaged with the real environment. Consequently, when GPS device are out of access, malfunction, or simply give wrong directions, people may not be well prepared to react to unexpected environmental conditions and find alternative action plans. Such mental unreadiness may cause safety problems in emergency situations. In this paper, we discuss the importance of building spatial awareness in wayfinding activities, analyze GPS features and constraints, and propose the context-awareness design principles that may supplement the efficiency of GPS as well as keep people actively engaged in exploration.