Terrestrial/land mobile satellite considerations, NASA plans and critical issues

The land mobile market is reviewed briefly, and services that might be provided by hybrid terrestrial/land mobile satellite systems (T/LMSS) are discussed. In view of the expected urban/ suburban patterns of planned terrestrial systems it is suggested that a satellite may prove a cost-effective complement to terrestrial systems for serving thinly populated or large geographical areas. A basic land mobile satellite system (LMSS) is described, example applications are provided, and the status and rationale for LMSS frequencies in the 806-890 MHz band are given. Next, examples are given of NASA supported land mobile satellite experiments, and a preliminary T/LMSS work plan, part of an overall narrowband (NB) program, is presented for structuring future work. The initiation of the T/LMSS plan depends on pending management/budget decisions. In conclusion a listing of issues and potential problem areas are given, the solutions of which NASA believes are critical to the success of the proposed T/LMSS effort.