Ranging and processing system for mobile surveillance and data link
First Claim
1. A ranging and processing satellite system for data link with and cooperative surveillance of a plurality of mobile units from multiple control facilities comprising:
- at least two satellites including means for discretely polling individual mobile units requested by one or more of the control facilities and for receiving replies from the polled mobile units, such replies including information about the mobile units'"'"' positions;
means operable in connection with the means for polling and for receiving replies, for precluding garbling between replies to polls initiated by the at least two satellites;
a cross-link communication path between the at least two satellites to exchange mobile ranging data;
processing means on at least one of the satellites to store poll commands, initiate polls according to an optimal sequence that fills in the guard times between polls with other messages, store messages between mobile units and control facilities, and to compute the ranges between the mobile unit and each of the satellites from the replies from the mobile units; and
means for transmitting the computed ranges to at least one of the control facilities.
1 Assignment
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Accused Products
Abstract
The satellite system includes at least two satellites having on-board processing capability so that data messages may be exchanged and the position of mobiles may be determined with direct access from multiple ground control facilities. The satellites transmit data and poll individual mobiles upon command by one or more of the control facilities and receive replies from the mobiles including the mobiles'"'"' altitude and other data of interest to the control facility. The at least two satellites communicate with one another by means of a cross-link communication path. Computer processing apparatus is included on the satellites to compute the ranges between the mobiles and each of the satellites from the replies received from the mobiles, and to store and process messages. The position information and messages are transmitted to at least one of the control facilities. It is preferred that the control facilities employ TDMA or FDMA protocols in the uplinks to the satellites. The on-board processing makes it readily possible for a number of control facilities to gain access to the satellites directly rather than through a central earth station, and to increase the capacity of a discrete address polling system for a given allocation of radio frequency spectrum. A discrete address polling system is one where each mobile is polled on an individual basis by only responding to polls that contain its identification.
71 Citations
7 Claims
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1. A ranging and processing satellite system for data link with and cooperative surveillance of a plurality of mobile units from multiple control facilities comprising:
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at least two satellites including means for discretely polling individual mobile units requested by one or more of the control facilities and for receiving replies from the polled mobile units, such replies including information about the mobile units'"'"' positions; means operable in connection with the means for polling and for receiving replies, for precluding garbling between replies to polls initiated by the at least two satellites; a cross-link communication path between the at least two satellites to exchange mobile ranging data; processing means on at least one of the satellites to store poll commands, initiate polls according to an optimal sequence that fills in the guard times between polls with other messages, store messages between mobile units and control facilities, and to compute the ranges between the mobile unit and each of the satellites from the replies from the mobile units; and means for transmitting the computed ranges to at least one of the control facilities. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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Specification