FIELD

The present disclosure relates to aeronautical broadband communication systems such as Aeronautical Earth Station in Motion (A-ESIM) which communicate with fixed satellite service.

BACKGROUND

In the aviation domain, commercial and business aviation provide broadband communications, e.g., for passenger Internet connectivity, using Fixed Satellite Service (FSS) in the Ka-band frequency band, 27.5-30 GHz. The International Telecommunication Union (ITU) in World Radiocommunication Conference 2019 (WRC-19) adopted a new resolution to share the Ka-band frequency (27.5 GHz to 29.5 GHz) with Aeronautical Earth Station in Motion (A-ESIM) terminals which include aircraft and terrestrial applications, generally for 5G standard communications. The resolution from WRC-19 is expected to be adopted globally by member states in the near future. An A-ESIM terminal must comply with a regulatory power flux density (PFD) envelope to protect the terrestrial services operating in the shared frequency band. The term “A-ESIM” is also referred to herein as “ESIM” which is an example embodiment of a “broadband communication system” for an aircraft.

Aeronautical broadband communication because of its dynamic and global nature adds to the additional complexity in complying with the PFD requirement defined by ITU. Sufficient technology to dynamically and adaptively control the PFD of A-ESIM terminal is not available today. Service by an A-ESIM terminal should be disabled, e.g., by disabling transmission from the aircraft, if any of a regulatory PFD envelope for a region on the ground is exceeded. Although it serves the primary goal of complying with the regulatory PFD envelope to avoid excessive interference to terrestrial communication systems, this approach of disabling transmissions creates penalties in the form of reduced data rate, lower spectral efficiency, poor broadband connectivity availability, and increased cost of connectivity service.

SUMMARY

Some embodiments are directed to a broadband communication system aboard an aircraft that includes a steerable antenna, a modem, and processing circuitry. The steerable antenna produces 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 that are increasingly angularly offset away from the primary axis. The modem is configured to output data traffic for transmission through the steerable antenna. The processing circuitry is configured to obtain obtain aircraft altitude, attitude, and location, and to determine target satellite coordinates indicating direction from the aircraft to the target satellite, based on the aircraft altitude, attitude, and location. The processing circuitry controls the steerable antenna to steer the primary axis of the main lobe of the ESD pattern toward the target satellite based on the target satellite coordinates. The processing circuitry determines 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. The processing circuitry determines a regulatory power flux density (PFD) envelope based on the region on the ground. The processing circuitry estimates 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. The processing circuitry determines, 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. The processing circuitry controls 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.

Some other related embodiments are directed to a broadband communication system for an aircraft. The aircraft includes a steerable antenna configured to produce an 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. The aircraft further includes a modem configured to output data traffic for transmission through the steerable antenna. The broadband communication system includes processing circuitry configured to be coupled to the high power amplifier, the processing circuitry is configured to operate to obtain aircraft altitude, attitude, and location, and to 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. The processing circuitry is further configured to determine a regulatory PFD envelope based on the region on the ground, and to 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. The processing circuitry is further configured to 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. The processing circuitry is further configured to 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.

Some other related embodiments are directed to a computer program product that includes 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 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. The aircraft further includes 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 that obtain aircraft altitude, attitude, and location. The operations 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. The operations determine a regulatory PFD envelope based on the region on the ground. The operations 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. The operations 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. The operations 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

Other broadband communication systems, computer program products, and related methods according to embodiments of the inventive subject matter will be or become apparent to one with skill in the art upon review of the following drawings and detailed description. It is intended that all such additional broadband communication systems, computer program products, and related methods be included within this description, be within the scope of the present inventive subject matter, and be protected by the accompanying claims. Moreover, it is intended that all embodiments disclosed herein can be implemented separately or combined in any way and/or combination.

