Method and apparatus for avoiding exceeding interference limits for a non-geostationary satellite system

A satellite comprising:

• an antenna;
• a transponder coupled to the antenna;
• and
• a satellite controller configured to:
• control the transponder so that the antenna forms a beam pattern comprising a set of beams in a footprint of the satellite, each beam having a first median and a second median, each beam being narrow along its first median and wide along its second median, wherein the first medians are substantially collinear with each other and the second medians are substantially oriented east to west wherein the satellite is a non-geostationary satellite and is part of a non-geostationary satellite system;
• determine for each beam of the set of beams whether the beam at a current power level would result in a total power from the satellite at a geosynchronous orbit (GSO) exclusion zone on the Earth's surface to exceed an equivalent power flux density (EPFD) limit specified in relation to a geostationary satellite, wherein the determining uses predetermined limits based on a current location of the satellite in a non-geosynchronous orbit (NGSO) and the beam pattern of the satellite;
• and
• for each beam, adjust the current power level of the beam based on the determination, wherein the satellite controller is further configured to adjust the current power level of the beam by:
• attenuating the current power level of the beam when the total power exceeds the EPFD limit as an angle of transmission of the beam approaches a direction of transmission of the geostationary satellite;
• or
• increasing the current power level of the beam as the angle of transmission of the beam recedes from the direction of transmission of the geostationary satellite to a point of maximum power level that does not cause the total power to exceed the EPFD limit when the total power is below the EPFD limit.

A satellite comprising:

• an antenna;
• means for forming a beam pattern comprising a set of beams of the antenna of a satellite in a footprint of the satellite, each beam having a first median and a second median, each beam being narrow along its first median and wide along its second median, wherein the first medians are substantially collinear with each other and the second medians are substantially oriented east to west, wherein the satellite is a non-geostationary satellite and is part of a non-geostationary satellite system;
• means for determining for each beam of the set of beams whether the beam at a current power level would result in a total power from the satellite at a geosynchronous orbit (GSO) exclusion zone on the Earth's surface to exceed an equivalent power flux density (EPFD) limit specified in relation to a geostationary satellite, wherein the determining uses predetermined limits based on a current location of the satellite in a non-geosynchronous orbit (NGSO) and the beam pattern of the satellite;
• and
• for each beam, means for adjusting the current power level of the beam based on the determination, wherein the means for adjusting the current power level of the beam comprises:
• means for attenuating the current power level of the beam when the total power exceeds the EPFD limit as an angle of transmission of the beam approaches a direction of transmission of the geostationary satellite;
• or
• means for increasing the current power level of the beam as the angle of transmission of the beam recedes from the direction of transmission of the geostationary satellite to a point of maximum power level that does not cause the total power to exceed the EPFD limit when the total power is below the EPFD limit.

A non-transitory computer-readable media having stored instructions that when executed by a processor, the processor on board a satellite having an antenna, cause the processor to perform a method comprising:

• forming a beam pattern comprising a set of beams of an antenna of a satellite in a footprint of the satellite, each beam having a first median and a second median, each beam being narrow along its first median and wide along its second median, wherein the first medians are substantially collinear with each other and the second medians are substantially oriented east to west, wherein the satellite is a non-geostationary satellite and is part of a non-geostationary satellite system;
• determining for each beam of the set of beams whether the beam at a current power level would result in a total power from the satellite at a geosynchronous orbit (GSO) exclusion zone on the Earth's surface to exceed an equivalent power flux density (EPFD) limit specified in relation to a geostationary satellite, wherein the determining uses predetermined limits based on a current location of the satellite in a non-geosynchronous orbit (NGSO) and the beam pattern of the satellite;
• and
• for each beam, adjusting the current power level of the beam based on the determination, wherein the adjusting the current power level of the beam comprises:
• attenuating the current power level of the beam when the total power exceeds the EPFD limit as an angle of transmission of the beam approaches a direction of transmission of the geostationary satellite;
• or
• increasing the current power level of the beam as the angle of transmission of the beam recedes from the direction of transmission of the geostationary satellite to a point of maximum power level that does not cause the total power to exceed the EPFD limit when the total power is below the EPFD limit.