AetherMMS: a space-time GNSS mission planning framework for mobile mapping systems

AetherMMS is an open-source Python tool for planning Mobile Mapping System (MMS) surveys, particularly in urban and partially obstructed environments, where acquisition quality depends on both the survey route and the time at which it is driven. The software package reconstructs the survey scene from a planned trajectory, terrain elevation data, building footprints and vegetation layers, propagates GPS and Galileo almanacs, and ray-traces every satellite-receiver line of sight at its observation epoch. Satellite links are classified as line-of-sight, obstructed, vegetation-degraded or GNSS-denied, while visible satellite count, Position Dilution of Precision (PDOP) and a Sky Visibility Index (SVI) are evaluated along the route. A planning routine ranks candidate acquisition windows and identifies critical trajectory segments. The distinctive feature of AetherMMS is the explicit coupling between the spatial progression of the survey trajectory and the temporal evolution of the satellite constellations, enabling route-aware and time-aware GNSS mission planning. Route-based validation shows that AetherMMS identifies GNSS-denied sections along the open-sky route crossed by short tunnels and covered roads, while in the dense urban canyon considered in this study the obstruction model removes on average 35% of the otherwise visible satellites. In a dedicated field experiment, surveying the same urban route during the acquisition window predicted as most favorable increased the share of ambiguity-fixed epochs more than fourfold, from 6.3% to 25.7%, and extended the route length covered by a continuous fixed solution from 56 m to 744 m. The source code, example dataset and user manual are freely available.