Method and apparatus for beam selection for a multibeam, multi-satellite communications system

The system of claim 5, wherein for each of the plurality of user spot beams the normalized distance metric is calculated according to the equation:

• D
• i
• =
• (
• (
• x
• -
• x
• i
• )
• 2
• +
• (
• y
• -
• y
• i
• )
• 2
• R
• i
• )
• W
• i
• where Di is the normalized distance metric, (x, y) is the location of the mobile satellite terminal in horizontal (azimuth (az)/elevation (el)) or U/V coordinates, (xi, yi) is the location of the center of the user spot beam in one of az/el or U/V coordinates, Ri is the radius of the user spot beam, and Wi is the weight given to the user spot beam.

The system of claim 6 wherein the radius Ri is calculated according to the equation:

• R
• i
• =
• (
• (
• R
• 1
• 
• 
• i
• *
• cos
• 
• (
• θ
• i
• -
• a
• i
• )
• *
• cos
• 
• (
• a
• i
• )
• -
• R
• 2
• 
• 
• i
• *
• sin
• 
• (
• θ
• i
• -
• a
• i
• )
• *
• sin
• 
• (
• a
• i
• )
• 2
• +
• (
• R
• 2
• 
• 
• i
• *
• sin
• 
• (
• θ
• i
• -
• a
• i
• )
• *
• cos
• 
• (
• a
• i
• )
• +
• R
• 1
• 
• 
• i
• *
• cos
• 
• (
• θ
• i
• -
• a
• i
• )
• *
• cos
• 
• (
• a
• i
• )
• )
• )
• 2
• )
• where R1i is the semi-major axis of the user spot beam, R2i is the semi-minor axis of the user spot beam, ai is the tilt angle of the user spot beam, and is calculated according to the equation:
• θi=arctan((y−y01)/(x−x01))
• where (x01, y01) is the location of the centroid of the user spot beam.

A method, comprising:

• determining a current location of a mobile satellite terminal comprising an antenna configured to send and receive RF signals;
• identifying a plurality of user spot beams providing coverage to the determined current location;
• calculating a normalized distance metric for each of the plurality of user spot beams;
• identifying a user spot beam of the plurality of user spot beams having a lowest normalized distance metric;
• and
• selecting the user spot beam having the lowest normalized distance metric and a satellite associated with the user spot beam having the lowest normalized distance metric.

A system comprising:

• one or more non-transitory computer-readable mediums having instructions stored thereon that, when executed by one or more processors, cause the system to:
• determine a plurality of user spot beams available to a mobile satellite terminal during a predetermined route based on a stored table of user spot beam parameters, the user spot beam parameters comprising the locations of centers and radii of each of the plurality of user spot beams;
• calculate a normalized distance metric for each of the plurality of user spot beams available during the predetermined route;
• and
• using at least the calculated normalized distance metric for each of the plurality of user spot beams, preselect one or more of the plurality of user spot beams for the route.

A method, comprising:

• determining a plurality of user spot beams available to a mobile satellite terminal during a predetermined route based on a table of user spot beam parameters stored in a memory, the user spot beam parameters comprising the locations of centers and radii of each of the plurality of user spot beams;
• calculating a normalized distance metric for each of the plurality of user spot beams available during the predetermined route;
• and
• using at least the calculated normalized distance metric for each of the plurality of user spot beams, preselect one or more of the plurality of user spot beams for the route.