Ground control of forward link assignments

DETAILED DESCRIPTION In one preferred form, the present invention provides a communications system and method that transmits forward link transponder assignments from a ground station to a mobile platform, such as an aircraft, through the novel use of a default transponder assignment table.
The default transponder assignment table is loaded onto receiver equipment of the mobile platform and contains assignments to a plurality of transponders on a plurality of satellites around the world.
If the mobile platform receiver equipment fails and the current forward link transponder assignments are lost, the receiver equipment reverts to the default transponder assignment table to receive a temporary transponder assignment.
Although the temporary transponder assignment is incorrect for the specific mobile platform, the transponder that is subsequently linked sends a required return link to the receiver equipment so that the receiver equipment can in turn contact the ground station for the correct forward link transponder assignments.
As set forth, the communications system of the present invention requires that the mobile platform have a return link to a ground station before the correct forward link transponder assignments can be transmitted.
The return link is required so that the ground station can confirm any changes in data types required by the mobile platform.
Additionally, the ground station comprises a prioritized list of all transponders on all satellites for all regions around the world.
The prioritized list is then utilized by the mobile platform to tune its receivers to the highest priority transponders for subsequent data communications.
In another preferred form, the present invention provides a communications system and method that provides forward link transponder assignments from a piece of communications equipment to a piece of receiver equipment on the mobile platform in the event of receiver equipment failure.
Initially, the correct forward link transponder assignments for the mobile platform are mirrored onto the piece of communications equipment on the same mobile platform