Geometrical instruments – Gauge – Collocating
Reexamination Certificate
1999-07-30
2001-03-20
Gutierrez, Diego (Department: 2859)
Geometrical instruments
Gauge
Collocating
C702S150000, C702S152000
Reexamination Certificate
active
06202317
ABSTRACT:
FIELD OF THE INVENTION
The present invention generally relates to satellite communication, and more particularly relates to mobile satellite communication, and even more particularly relates to apparatuses and methods for controlling the operation of a mobile satellite transceiver.
BACKGROUND OF THE INVENTION
In the past, avionics engineers have endeavored to change the operation of a mobile transceiver depending upon the location of the transceiver with respect to the boundaries of geographic areas which have predetermined exposure to satellite signals for satellite communication. These predetermined geographic areas are often referred to as spot beams. If an aircraft is within the spot beam, the satellite communication transceiver will be operated differently than if it is outside of a spot beam. However, since aircraft travel at relatively high velocity, they may enter and exit several spot beams during a single flight. In the past, determining whether the aircraft is in a spot beam has often taken considerable time and consumed valuable computing resources on the aircraft.
One well-known approach has been to draw a line from the given point to any point that is known to be outside of the spot beam boundary (polygon), e.g. to infinity, and then counting the number of times the line intersects the polygon boundary. If the number of intersections is odd, then the given point is inside the polygon. If the number of intersections is even, then the point is outside the polygon. The same method can be applied to spherical coordinates; i.e. let the North Pole be the point outside of the polygon; this can be assumed for the case of a geo-stationary satellite spot beam.
However, some of these prior art methods do not always accurately determine the presence of the aircraft within a spot beam, especially with respect to intersections occurring at vertices of the line segments of the polygon.
Consequently, there exists a need for improvement in methods and apparatuses for determining whether a mobile transceiver is within a spot beam.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide enhanced quality of the determination of presence within a spot beam.
It is a feature of the present invention to use a slight latitudinal displacement of the current position in the process of determining location within a spot beam.
It is an advantage of the present invention to reduce ambiguity resulting from infinity lines drawn through vertices between adjacent line segments of the polygon.
It is another advantage of the present invention to reduce the computing resources necessary to make the spot beam determination with an adequate level of certainty.
The present invention is an apparatus and method for determining the location of a mobile satellite transceiver within a spot beam, which is designed to satisfy the aforementioned needs, provide the previously stated objects, include the above-listed features and achieve the already articulated advantages. The present invention is carried out in an “ambiguity-less manner” in a sense that the ambiguity associated with an intersection of a line drawn to infinity and through a vertex of two adjacent line segments of the spot beam polygon boundary, is greatly reduced.
Accordingly, the present invention is a system and method for determining presence within a spot beam by making a displacement of the current position and making a presence determination from the new position.
REFERENCES:
patent: 6016606 (2000-01-01), Oliver et al.
patent: 6072430 (2000-06-01), Wyrwas et al.
Eppele Kyle
Guadalupe Yaritza
Gutierrez Diego
Jensen Nathan O.
O'Shaughnessy J. P.
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