Collecting high-resolution aeromagnetic data require sensors to be active at lower above ground level altitudes. Cost associated is the driving factor for pursuing remotely piloted aircraft systems. Operators have been considering these systems to complement manned aircraft surveillance missions. To provide accurate aeromagnetic readings, remotely piloted aircraft must fly low at constant above ground level altitudes and therefore follow the terrain. A low-cost, non-proprietary terrain following system for remotely piloted aircraft is being developed to measure ground and surface altitude, fly at specific above ground level altitudes, and follow preloaded flightpaths from a smoothed terrain drape to maximize the quality of aeromagnetic data. Using digital elevation models, a smooth flightpath is predetermined so remotely piloted aircraft can follow the terrain without exceeding its structural loads or flight envelope; this process creates a terrain drape profile, which is loaded onto the autopilot system to follow the ground at the desired altitude.