Architectural Considerations for Low Latency ARINC 818 Video Concentrators

Many aerospace systems include sensor pods for enhanced vision (EVS), mid-air refueling, intelligence, surveillance, reconnaissance (ISR), and infrared countermeasures. Within the pods are multiple high-resolution sensors (infrared and optical) working in unison. One of the architectural features enabled by ARINC 818, the Avionics Digital Video Bus, is the concentration of multiple video streams onto a single video link. Although this capability has been part of the ARINC 818 protocol since its inception, only recently has there been more serious interest in ARINC 818 video concentrators.This paper explores architectural considerations for designing low-latency concentrators (multiplexers) and de-concentrators (de-mux) used in aerospace environments. To implement a low latency concentrator/de-concentrator, it is important to consider the link rates of the sensors, sensor synchronization, the number of channels, the latency budget, and the synchronization class required by the de-concentrator (found in the video processor). Tradeoffs of different architectural choices are compared. Finally, an architectural overview and latency results are presented for an ultra-low latency pair (concentrator/de-concentrator) suitable for implementations both within the cockpit and mission systems.