Satellite terminal position determination
First Claim
1. A navigational satellite positioning system wherein a terminal is operable to receive time and orbit information from a plurality of navigational satellites to calculate the position of the terminal, said system including a communications network, operable to inform said terminal which of said plurality of navigational satellites are within range of said terminal, said terminal, in response thereto, listening only for those of said plurality of navigational satellites that are within range.
1 Assignment
0 Petitions
Accused Products
Abstract
A terminal 44 44A 44B using standard navigational satellite 142 position determination to find its position on the surface of the earth 14, has its performance enhanced by being linked to a communications satellite system 10 38. In one variant, the communications satellite 10 broadcasts on each of a plurality of spot beams 30, each interactive with a different part of the earth, the broadcast indicating which navigational satellites 142 are accessible for a terminal within that beam 30. The terminal 44 44A 44B receives the broadcast and adjusts the navigational satellite receiver 174 to look for signals only from the nominated navigational satellites 142. In another variant, the communications satellite system 10 38 approximately measures the position of the terminal 44 44B and then informs the terminal 44 44B which navigational satellites are accessible from the terminal 44 44B, the navigational satellite receiver 174 again only looking for signals from the nominated navigational satellites 142. In both variants, the time required to establish a position is reduced by the navigational satellite receiver 174 not being required to listen for inappropriate or inaccessible navigational satellites 142.
-
Citations
36 Claims
- 1. A navigational satellite positioning system wherein a terminal is operable to receive time and orbit information from a plurality of navigational satellites to calculate the position of the terminal, said system including a communications network, operable to inform said terminal which of said plurality of navigational satellites are within range of said terminal, said terminal, in response thereto, listening only for those of said plurality of navigational satellites that are within range.
-
2. A navigational satellite positioning system wherein a terminal is operable to receive time and orbit information from a plurality of navigational satellites to calculate the position of the terminal, said system including a communications network, operable to inform said terminal which of said plurality of navigational satellites are within range of said terminal, said terminal, in response thereto, listening only for those of said plurality of navigational satellites that are within range,
wherein said terminal is operable to exchange messages with said communications network to establish an approximate position for said terminal, wherein said communications network, in response to a knowledge of said approximate position, is operative to calculate which of said plurality of navigational satellites are within range of said terminal, and wherein said communications network is operative to inform said terminal which of said plurality of navigational satellites are within range of said terminal.
-
29. A method for use in a navigational satellite positioning system wherein a terminal is operative to receive time and orbit information from a plurality of navigational satellites to calculate the position of the terminal, said method including the steps of:
-
including said terminal in a communications network; employing said communications network to inform said terminal which of said plurality of navigational satellites are within range of said terminal, and in response thereto, listening with said terminal, only for those of said plurality of navigational satellites that are within range.
-
- 30. A terminal for use in a navigational satellite positioning system wherein said terminal is operative to receive time and orbit information from a plurality of navigational satellites to calculate the position of said terminal, wherein the terminal is operable in a communications network that informs said terminal which of said plurality of navigational satellites are within range of said terminal, and said terminal, in response thereto, being operative to listen only for those of said plurality of navigational satellites that are within range.
- 34. A node for a communication network for use with a navigational satellite positioning system wherein the node is configured to calculate the position of a terminal and to receive time and orbit information for a plurality of navigational satellites, in which the node is configured to send time and orbit information for a plurality of navigational satellites that have been determined to be within range of the user terminal, to permit the terminal to determine its position with reference to the satellites.
-
36. A navigational satellite positioning system wherein a terminal is operable to receive time and orbit information from a plurality of navigational satellites and to calculate the position of the terminal, and wherein the terminal is configured to communicate with a communications network, the system characterized in that the communications network is operable to exchange messages with the user terminal to calculate an approximate position of the terminal and to inform the terminal which of the said plurality of navigational satellites are within range of the terminal, and characterized by the terminal, in response thereto, listening only for those of the plurality of navigational satellite that are within range.
Specification