Diversity reception for aeronautical packet data communications systems

#The present invention is directed to the enhancement of air/air packet data communications reliability among aircraft, and the enhancement of air/ground packet data communications reliability between aircraft and ground systems.

#Aircraft commonly transmit and receive analog voice radio communications, to enable air traffic control and provide for other air traffic services (ATS), via radio equipment operating on selected frequency channels. A single aircraft typically supports at least one radio, and may support several radios, each radio tuned to a different frequency channel. Analog voice communications in the VHF band use frequency channels separated by 25 kHz between channel centers, and also 8.33 kHz between channel centers. The aviation industry is currently developing a digital voice and data capability for ATS which will also operate on 25 kHz channels in the VHF band.

#Commercial aircraft may additionally support analog and digital air/ground communications for airline operational control (AOC). One example used in the VHF band is the Aircraft Communications Addressing and Reporting System (ACARS). The ACARS air/ground environment is described in ARINC Specification 618. The capabilities of onboard equipment are defined in ARINC Characteristics 597, 724 and 724B. Other standards may also apply. The aviation industry is also currently developing enhanced systems for AOC communications which will provide higher data rates and improved networking protocols than those which are available via ACARS.

#FIG. 1 illustrates a dual-redundant configuration of antennas and radio LRUs known to the prior art.

#FIG. 2 illustrates an embodiment of the present invention comprising two multi-channel radio LRUs each connected to a separate antenna, wherein each radio LRU contains a data arbitrator designed to operate with one or more peer radio LRUs in a distributed architecture.

#A preferred embodiment of the present invention will be set forth with reference to FIG. 2.

#FIG. 2 illustrates a preferred embodiment of the present invention wherein a first antenna 21 and radio LRU 22, and a second antenna 23 and radio LRU 24, each contain a data arbitrator element 25. In this embodiment the two radio LRUs operate as cooperative peers and exchange data automatically to assist each other in achieving operational requirements. The radio LRUs may be single-channel or multi-channel, analog or digital or hybrid, and operate in any band, although for the purpose of the present invention they must be tuneable to the same frequencies and the benefits of at least one preferred embodiment of the present invention are only available on frequencies where packet data transmissions are supported.

#Each radio LRU 22 and 24 receives configuration commands (e.g., tuning frequency, applications to be supported) and data for transmission from external systems, and delivers data it has received, and communicates its current status, to external systems. An interwiring means such as a wiring harness 29 connects the data arbitrators 25 of the various radio LRUs. The interwiring means may be direct or may alternatively pass through intermediate systems.