A data routing subsystem (200) for a communication satellite includes an inbound module (602) that accepts demodulated uplink data. The inbound module (602) includes a routing table (702) that stores queue tags (714) specifying downlink beam hop locations (302, 304) for the uplink data. The subsystem (200) also includes a self addressed packet switch (608) having an input port coupled to the inbound module (602), and an outbound module (610) coupled to an output port of the switch (608). A memory (804) in the outbound module (610) stores the uplink data in accordance with the downlink beam hop locations (302, 304). A multiple beam array antenna (116-122) is coupled to the outbound module (610). The multiple beam array antenna (116-122) includes a first feed element (116) assigned to a first downlink beam hop location (302) and a second feed element (118) assigned to a second downlink beam hop location (304).

An antenna system 10 for a communications satellite which transmits and receives communications from ground based devices. The system includes an antenna array 16 containing a plurality of feed elements 18 which cooperate to receive or transmit coverage beams arranged in a circular layout at a coverage area in a far-field region proximate the surface of the earth. The feed elements 18 are arranged in a non-circular layout within the antenna array 16. This system further includes a beam forming network 14 for mapping coverage beam signals onto feed signals which drive the antenna array 16. The beam forming network 14 includes a beam forming matrix 28 and a beam connecting network 30. The beam connecting network 30 separates each coverage beam signal into a plurality of component signals weighted to have differing amplitudes from one another. The component signals are delivered to the beam forming matrix 28 which in turn produces corresponding feed signals to drive the antenna array 16 in such a manner as to form feed beams which cooperate to define the coverage beams at the far-field region. The beam connecting network 30 weights the component signals unevenly in order to shift corresponding resultant coverage beams inward or outward until aligned within the coverage area in a circular layout along concentric circles.

A dual phased array payload (100) for use onboard a communications satellite is disclosed. The payload includes one or more phased array receive antennas (102-108) including numerous individual receiving elements distributed in a predetermined configuration. Each of the individual radiating elements is selectively adjustable in amplitude and phase to achieve scanning beams for receiving information transmitted from the ground in an uplink beam. The payload includes a packet switch (114) connected to the phased array receive antennas (102-108). The packet switch (114) includes a set of inputs and a set of outputs. The set of inputs are selectively connectable to the set of outputs. The payload (100) includes one or more phased array transmit antennas (120-126) connected to the packet switch (114). The phased array transmit antennas (120-126) include numerous individual radiating elements distributed in a predetermined configuration. Each of the individual radiating elements has a controllable amplitude and phase excitation used to electronically steer a downlink beam produced by the phased array transmit antennas (120-126). A payload computer (132) is connected to the packet switch (114). The payload computer includes outputs that control the connection of the packet switch inputs to the packet switch outputs. The communications satellite may communicate with the ground, or with other satellites, using a beacon (128). The beacon (128) operates under control of the payload computer (132) to transmit and receive command, control, and status information to the ground.

This invention concerns improvements in the efficiency and flexibility of multi-beam communications satellites connected by intersatellite links. It will increase the number of customers serviced and hence the revenue generated when intersatellite links are employed by multibeam satellites which use the currently available technology in a bent-pipe microwave architecture.

Existing multibeam systems use the bent-pipe microwave architecture. Information from one geographic region uplinked to one satellite can be transferred to a second satellite via intersatellite link and then downlinked into a second geographic region. These multibeam systems waste available bandwidth capacity by tying up complete intersatellite link transponders even if the channels are not full because information switching is conducted at a full transponder level. Further, if information is broadcast, as in news-gathering applications, to several downlink beams, the system ties up, in the receiving satellite, one transponder per downlink beam.

In future systems using on-board digital-processing technology, it is theoretically possible that information can be switched at a much finer bandwidth level. Hence, one intersatellite channel could handle traffic originating from several uplink beams on the first satellite with destinations to several downlink beams on the second satellite which avoids the inefficiency of a partially full transponder. However, customer terminals have to be designed for the modulation and coding architecture specific to that system and cannot be used with any other system.

The present invention solves spectral flexibility and inefficiency problems of existing systems, and is transparent to all modulation and coding architectures while still allowing for communication with all terminals currently in use with communications satellites. The approach used is to combine switching at a subchannel level (solving flexibility and inefficiency problems) while using technologies compatible with bent-pipe architecture (solving terminal-compatibility problems) with an intersatellite link. Technologies used include Surface Acoustic Wave (SAW) filtering and solid-state switching.

This invention will provide spectral efficiency and flexibility approaching but not equalling the theoretical efficiency and flexibility of future systems employing digital signal processing. It will, however, be significantly more efficient than future digital satellite systems in terms of the two most expensive satellite resources, power and mass.

Each user signal of a communications network is encoded using a narrowband traffic code and a wideband cover code for transmission to a signal relay (e.g., a communications satellite) in one of a plurality of uplink signal beams. The signal relay receives all of the user signals in the different uplink signal beams and processes them to re-transmit them in different downlink signal beams to their different appropriate destinations. The narrowband traffic codes and wideband cover codes are selected to encode the individual user signals in such a way as to permit the switching processing of the signal relay to be implemented at the beam level (e.g., individual components processing multiple user signals at a time) rather than at the user level (e.g., one switching circuit for each user). For example, in one embodiment, all user signals within the same signal beam are encoded using different narrowband codes and the same wideband cover code, while user signals in different signal beams are encoded using different wideband cover codes. The present invention enables a reduction in the volume and cost of switching equipment within the signal relay. Furthermore, much of the switching processing can be implemented at intermediate frequencies (IF) using conventional, relatively inexpensive radio frequency (RF) components.