Scheduling beams of a satellite antenna

Abstract

In one implementation, a method for scheduling beams of an antenna on a satellite during a defined time period includes calculating a beam score for each beam based on the expected gain of the beam and determining that the number of beams having non-zero beam scores during the defined time period is less than a threshold value. In addition, the method also includes accessing a set of beam weights for each of multiple different candidate beam patterns, and, for each set of weights, multiplying individual beam weights by corresponding beam scores, and generating a candidate beam pattern score by calculating a sum of the products of the beam weights and corresponding beam scores. The method further includes comparing the candidate beam pattern scores, selecting a particular one of the candidate beam patterns, and scheduling the selected beam pattern for the defined time period.

What is claimed is: 
     
         1 . A computer-implemented method for scheduling beams of an antenna on board a satellite in low-Earth orbit for receiving Automatic Dependent Surveillance Broadcast (ADS-B) messages, wherein the antenna is configured to provide multiple different beams, the method comprising:
 identifying, for beams that the antenna is configured to provide, corresponding coverage areas during a defined period of time;   identifying characteristics of the identified coverage areas; and   scheduling individual beams that the antenna is configured to provide to be on or off during the defined period of time based on the identified characteristics of their corresponding coverage areas.   
     
     
         2 . The computer-implemented method of  claim 1 , wherein:
 identifying characteristics of the identified coverage areas includes identifying at least one particular coverage area as an area for which coverage is desired; and   scheduling individual beams that the antenna is configured to provide to be on or off during the defined period of time includes scheduling the beam identified as corresponding to the particular coverage area to be on during the defined period of time as a consequence of having identified the particular coverage area as an area for which coverage is desired.   
     
     
         3 . The computer-implemented method of  claim 2 , wherein scheduling the beam identified as corresponding to the particular coverage area to be on during the defined period of time includes scheduling the beam identified as corresponding to the coverage area to be on for a portion of the defined period of time that is less than all of the defined period of time. 
     
     
         4 . The computer-implemented method of  claim 1 , wherein:
 identifying characteristics of the identified coverage areas includes identifying at least one particular coverage area as an area for which coverage is not desired; and   scheduling individual beams that the antenna is configured to provide to be on or off during the defined period of time includes scheduling the beam identified as corresponding to the particular coverage area to be off during the defined period of time as a consequence of having identified the particular coverage area as an area for which coverage is not desired.   
     
     
         5 . The computer-implemented method of  claim 1 , wherein:
 identifying characteristics of the identified coverage areas includes identifying desired update intervals for aircraft within the identified coverage areas; and   scheduling individual beams that the antenna is configured to provide to be on or off during the defined period of time based on the identified characteristics of their corresponding coverage areas includes scheduling individual beams that the antenna is configured to provide to be one or off during the defined period of time based on the desired update intervals for aircraft within the identified coverage areas.   
     
     
         6 . The computer-implemented method of  claim 1 , wherein:
 identifying characteristics of the identified coverage areas includes identifying expected aircraft density within the identified coverage areas; and   scheduling individual beams that the antenna is configured to provide to be on or off during the defined period of time based on the identified characteristics of their corresponding coverage areas includes scheduling individual beams that the antenna is configured to provide to be on or off during the defined period of time based on the expected aircraft density within the identified coverage areas.   
     
     
         7 . The computer-implemented method of  claim 1 , wherein:
 identifying characteristics of the identified coverage areas includes identifying expected interference with ADS-B messages within the identified coverage areas; and   scheduling individual beams that the antenna is configured to provide to be on or off during the defined period of time based on the identified characteristics of their corresponding coverage areas includes scheduling individual beams that the antenna is configured to provide to be on or off during the defined period of time based on the expected interference with ADS-B messages within the identified coverage areas.   
     
     
         8 . The computer-implemented method of  claim 1 , further comprising determining a power budget during the defined period of time, wherein:
 scheduling individual beams that the antenna is configured to provide to be on or off during the defined period of time based on the identified characteristics of their corresponding coverage areas further comprises scheduling individual beams that the antenna is configured to provide to be on or off during the defined period of time based on the identified characteristics of their corresponding coverage areas and the determined power budget.   
     
     
         9 . The computer-implemented method of  claim 8 , wherein identifying a power budget during the defined period of time includes:
 determining that the satellite is in eclipse during the defined period of time; and   determining a power budget during the defined period of time based on the satellite being in eclipse during the defined period of time.   
     
     
         10 . The computer-implemented method of  claim 8 , wherein identifying a power budget during the defined period of time includes:
 determining that solar power is available to the satellite during the defined period of time; and   determining a power budget during the defined period of time based on solar power being available to the satellite during the defined period of time.   
     
     
         11 . The computer-implemented method of  claim 1 , further comprising determining, for the beams that the antenna is configured to provide, expected gains during the defined period of time, wherein:
 scheduling individual beams that the antenna is configured to provide to be on or off during the defined period of time based on the identified characteristics of their corresponding coverage areas includes scheduling individual beams that the antenna is configured to provide to be on or off during the defined period of time based on the identified characteristics of their corresponding coverage areas and their corresponding expected gains.   
     
     
         12 . The computer-implemented method of  claim 1  wherein the antenna corresponds to a secondary payload on the satellite. 
     
     
         13 . The computer-implemented method of  claim 1 , wherein scheduling individual beams that the antenna is configured to provide to be on or off during the defined period of time based on the identified characteristics of their corresponding coverage areas includes scheduling at least one beam to be on for at least one portion of the defined period of time and off for at least another portion of the defined period of time. 
     
     
         14 . A system for scheduling beams of an antenna on board a satellite in low-Earth orbit for receiving Automatic Dependent Surveillance Broadcast (ADS-B) messages, wherein the antenna is configured to provide multiple different beams, the system comprising:
 one or more processing elements; and   non-transitory computer-readable memory storing instructions that, when executed by the one or more processing elements, cause the system to:
 identify, for beams that the antenna is configured to provide, corresponding coverage areas during a defined period of time; 
 identify characteristics of the identified coverage areas; and 
 schedule individual beams that the antenna is configured to provide to be on or off during the defined period of time based on the identified characteristics of their corresponding coverage areas. 
   
     
     
         15 . The system of  claim 14 , wherein:
 the instructions that, when executed by the one or more processing elements, cause the system to identify characteristics of the identified coverage areas include instructions that, when executed by the one or more processing elements, cause the system to identify at least one particular coverage area as an area for which coverage is desired; and   the instructions that, when executed by the one or more processing elements, cause the system to schedule individual beams that the antenna is configured to provide to be on or off during the defined period of time include instructions that, when executed by the one or more processing elements, cause the system to schedule the beam identified as corresponding to the particular coverage area to be on during the defined period of time as a consequence of having identified the particular coverage area as an area for which coverage is desired.   
     
     
         16 . The system of  claim 14 , wherein:
 the instructions that, when executed by the one or more processing elements, cause the system to identify characteristics of the identified coverage areas include instructions that, when executed by the one or more processing elements, cause the system to identify at least one particular coverage area as an area for which coverage is not desired; and   the instructions that, when executed by the one or more processing elements, cause the system to schedule individual beams that the antenna is configured to provide to be on or off during the defined period of time include instructions that, when executed by the one or more processing elements, cause the system to schedule the beam identified as corresponding to the particular coverage area to be off during the defined period of time as a consequence of having identified the particular coverage area as an area for which coverage is not desired.   
     
     
         17 . A non-transitory computer-readable storage medium having computer-readable program code embodied thereon for scheduling beams of an antenna on board a satellite in low-Earth orbit for receiving Automatic Dependent Surveillance Broadcast (ADS-B) messages, wherein the antenna is configured to provide multiple different beams, the computer-readable program code comprising instructions that, when executed by one or more processing elements, cause the processing elements to:
 identify, for beams that the antenna is configured to provide, corresponding coverage areas during a defined period of time;   identify characteristics of the identified coverage areas; and   schedule individual beams that the antenna is configured to provide to be on or off during the defined period of time based on the identified characteristics of their corresponding coverage areas.   
     
     
         18 . The non-transitory computer-readable storage medium of  claim 17 , wherein:
 the instructions that, when executed by the one or more processing elements, cause the processing elements to identify characteristics of the identified coverage areas include instructions that, when executed by the one or more processing elements, cause the processing elements to identify at least one particular coverage area as an area for which coverage is desired; and   the instructions that, when executed by the one or more processing elements, cause the processing elements to schedule individual beams that the antenna is configured to provide to be on or off during the defined period of time include instructions that, when executed by the one or more processing elements, cause the processing elements to schedule the beam identified as corresponding to the particular coverage area to be on during the defined period of time as a consequence of having identified the particular coverage area as an area for which coverage is desired.   
     
     
         19 . The non-transitory computer-readable storage medium of  claim 17 , wherein:
 the instructions that, when executed by the one or more processing elements, cause the one or more processing elements to identify characteristics of the identified coverage areas include instructions that, when executed by the one or more processing elements, cause the one or more processing elements to identify at least one particular coverage area as an area for which coverage is not desired; and   the instructions that, when executed by the one or more processing elements, cause the processing elements to schedule individual beams that the antenna is configured to provide to be on or off during the defined period of time include instructions that, when executed by the one or more processing elements, cause the processing elements to schedule the beam identified as corresponding to the particular coverage area to be off during the defined period of time as a consequence of having identified the particular coverage area as an area for which coverage is not desired.   
     
     
         20 . The non-transitory computer-readable storage medium of  claim 17 , wherein:
 the instructions that, when executed by the one or more processing elements, cause the processing elements to identify characteristics of the identified coverage areas include instructions that, when executed by the one or more processing elements, cause the processing elements to identify expected aircraft density within the identified coverage areas; and   the instructions that, when executed by the one or more processing elements, cause the processing elements to schedule individual beams that the antenna is configured to provide to be on or off during the defined period of time based on the identified characteristics of their corresponding coverage areas include instructions that, when executed by the one or more processing elements, cause the processing elements to schedule individual beams that the antenna is configured to provide to be on or off during the defined period of time based on the expected aircraft density within the identified coverage areas.