This dissertation describes a novel method of providing position-location from
geosynchronous communication satellites. The Global Positioning System (GPS) has
become the standard for position-location and navigation in the world. It provides
extremely accurate coordinates to military users and slightly less accurate coordinates to
"non-authorized" users. Disadvantages of GPS are complexity and high cost. The U.S.
Department of Defense (DoD) has spent billions of dollars in developing and fielding the
system. Maintenance and GPS satellite replenishment costs will continue to climb.
A simpler, lower cost alternative to the GPS system is explored. This study
describes a position-location system using transponders on-board geosynchronous
communication satellites. The system uses three geosynchronous communication
satellites at a time to relay synchronized television signals. The signals provide a timing
system to measure the ranges from the satellites to the receiver. The least squares
method is used to calculate the location of the receiver.
A software model is developed to demonstrate the ability of the system to "track"
three geosynchronous satellites and calculate receiver position. A test is conducted to
demonstrate the use of television signals to provide timing for the system. The basic model
is further refined by adding perturbation forces which act on the satellites. The Intelsat
Eleven-Parameter algorithm is incorporated into the systenl model and provided the most
precise location of the satellites. The accuracy of the proposed system in determining the
position-location of the receiver is estimated based on the results of the simulation and the
test. Further research is proposed to build on the concepts discussed in this dissertation.
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