Abstract: A hierarchical modular arbitration architecture for a mobile platform guidance system is disclosed. In embodiments, the architecture comprises a hierarchy of arbitration layers, each arbitration layer narrower in scope than the layer above (e.g., mission objective arbitrators, route arbitrators, path arbitrators). Each arbitration layer includes one or more objective-based arbitrators in communication with one or more applications or modes. Each arbitrator receives control input (e.g., from the pilot, from aircraft sensors) and control signals from the level above, selecting a mode to make active based on decision agents within the arbitrator layer which control mode priorities and sequencing (e.g., some flight objectives may involve multiple arbitrators and their subject applications coordinating in sequence).