ABSTRACTThe main characteristics of both GPS (1.5 GHz) and Loran‐C (100kHz) navigation systems are reviewed, with emphasis on vehicular navigation applications. The effects of the GPS line‐of‐sight requirement and of Loran‐C signal attenuation in mountainous areas are illustrated using signal availability statistics collected for major roads located in British Columbia, Canada. The advantages of an integrated GPS/Loran‐C system are demonstrated using GPS and multichain digital Loran‐C receiver data collected along a 230 km road section. Signals sufficient for horizontal navigation (HDOP ≤ 5) are available approximately 60 percent of the distance in the case of GPS, 75 percent in the case of Loran‐C, and some 95 percent in the case of GPS/Loran‐C. The advantages of multichain versus single‐chain Loran‐C receiver operations in mountainous areas are also demonstrated. A performance analysis of the digital Loran‐C receivers used for