Adaptive power flux density control for aeronautical broadband system reducing interference to terrestrial communication systems

A broadband communication system for an aircraft including a steerable antenna configured to produce an effective isotropic radiated power (EIRP) spectral density (ESD) pattern with a main lobe having a primary axis that is steerable toward a target satellite and a sequence of side lobes increasingly angularly offset from the primary axis, and further including a modem configured to output data traffic for transmission through the steerable antenna, the broadband communication system comprising:

• processing circuitry configured to operate to:
• obtain aircraft altitude, attitude, and location;
• determine a region on the ground where the sidelobes are incident, based on the radiated signal power pattern of the steerable antenna and the aircraft altitude, attitude, and location;
• determine a regulatory power flux density (PFD) envelope based on the region on the ground;
• estimate PFD generated by the sidelobes in the region on the ground based on the ESD pattern of the steerable antenna and the aircraft altitude, attitude, and location;
• determine, based on the estimate of the PFD generated by the sidelobes in the region on the ground and based on the regulatory PFD envelope, a target ESD pattern for the steerable antenna;
• and
• control at least one of:
• 1) output power of the modem based on the target ESD pattern;
• and 2) bandwidth of the data traffic output by the modem based on the target ESD pattern.

A computer program product comprising:

• a non-transitory computer readable medium storing program instructions that is executable by at least one processor of a processing circuit of a broadband communication system aboard an aircraft, the aircraft includes a steerable antenna configured to produce an effective isotropic radiated power (EIRP) spectral density (ESD) pattern with a main lobe having a primary axis that is steerable toward a target satellite and a sequence of side lobes increasingly angularly offset from the primary axis, and further including a modem configured to output data traffic for transmission through the steerable antenna, the program instructions executed by the at least one processor causes the at least one processor to perform operations comprising:
• obtaining aircraft altitude, attitude, and location;
• determining a region on the ground where the sidelobes are incident, based on the radiated signal power pattern of the steerable antenna and the aircraft altitude, attitude, and location;
• determining a regulatory power flux density (PFD) envelope based on the region on the ground;
• estimating PFD generated by the sidelobes in the region on the ground based on the ESD pattern of the steerable antenna and the aircraft altitude, attitude, and location;
• determining, based on the estimate of the PFD generated by the sidelobes in the region on the ground and based on the regulatory PFD envelope, a target ESD pattern for the steerable antenna;
• and
• controlling at least one of:
• 1) output power of the modem based on the target ESD pattern;
• and 2) bandwidth of the data traffic output by the modem based on the target ESD pattern.