Airborne antenna ground projection

A computer for determining a far projection distance of a beam of an antenna on an airborne station, the antenna projecting the beam downward toward the ground at an angle of declination, the computer configured to:

• determine the far projection distance, based at least in part on a width of the beam and the angle of declination, the far projection distance being a lesser of:
• a first distance from the antenna to the ground of a 3 dB far projection;
• two times a second distance from the antenna to the ground of a 3 dB near projection;
• and
• a third distance from the antenna to the ground of a projection of the maximum antenna gain multiplied by the square root of two;
• determine a ground footprint of the beam of the antenna based at least in part on the determined far projection distance;
• and
• cause the antenna to be pointed based at least in part on the determined ground footprint of the beam of the antenna.

A method for determining a ground coverage footprint of a beam of an antenna mounted above the ground and projecting the beam downward toward the ground at an angle of declination, the method comprising:

• receiving a beam width and the angle of declination of the antenna;
• and
• determining a far projection distance based at least in part on the beam width and the angle of declination, the far projection distance defining the ground coverage footprint of the beam, the far projection distance being a lesser of:
• a first distance to the ground from the antenna, the first distance corresponding to a −3 dB far projection;
• twice a second distance to the ground from the antenna, the second distance corresponding to a −3 dB near projection;
• and
• a third distance to the ground of a projection of a maximum antenna gain multiplied by the square root of two;
• determining a ground footprint of the beam of the antenna based at least in part on the determined far projection distance;
• and
• causing the antenna to be pointed based at least in part on the determined ground footprint of the beam of the antenna.