Abstract: A local broadcast mode operation is implemented in a point-to-point satellite communications system (10) by utilizing a terrestrial reference terminal or phone (20) that is located within a desired zone of broadcast operation (24). A broadcast service provider (16) places a call to this reference phone through a terrestrial gateway (12) and at least one satellite (18, 19), and then transmits desired broadcast data to the reference phone. The reference phone receives the broadcast data and functions in a conventional manner to provide power control and related satellite handoff feedback information to the gateway. Authorized user terminals (22) within the zone of broadcast operation are enabled to receive the same signal transmitted to the reference phone by placing a call through the gateway to the broadcast service provider.

Abstract: A system and method for improving the accuracy of pseudorange error measurements at a receiving or user station by utilizing a communications satellite as an additional ranging source for providing navigational signal information, wherein the user station, in fixing its position on the Earth, receives a pseudorange signal directly from a GPS satellite and also a pseudorange indicative or pseudorange-error indicative signal from a communications satellite which re-broadcasts, a time tagged, indicative signal to serve as another observable in pseudorange equations computed in the user station. The communications satellite may receive a pseudorange signal directly, or an error indicative signal from an Earth-based station, for conversion into the pseudorange indicative or error indicative signal it transmits. A particular embodiment for incorporation in a communications satellite constellation, such as Globalstar.TM.

Abstract: A satellite perigee velocity augmentation method wherein a satellite is steered throughout the perigee velocity augmentation maneuver such that its thrust vector is always oriented approximately opposite to the direction of motion of the satellite. The satellite is pitched around a predetermined axis (e.g. the Y-axis) such that the thrust vector is always pointing approximately opposite to the direction of motion of the satellite. The satellite is steered during the perigee velocity augmentation maneuver in order to achieve the desired attitude wherein the thrust vector is always oriented approximately opposite to the direction of motion of the satellite is accomplished by pitching the satellite around the predetermined axis such that the thrust vector is always pointing approximately opposite to the direction of motion of the satellite. By steering the satellite in accordance with the present perigee velocity augmentation method, overall efficiency achieved is increased.