Standardizing Video-Based Avionics and Mission Systems around the ARINC 818-3 Video Bus

Modern aircraft rely more and more on a variety of optical and infrared of sensors that are used for avionics (navigation, landing assistance (EVS)) and missions (target tracking, aircraft protection (counter measures), and ISR). Video-based avionics and mission systems employ different video protocols and buses: including both digital-SDI, SMPTE 292, HDMI, Display Port, Ethernet (AFDX, TSN, TTE), ARINC 818 and analog (RGB, RS-170, CVBS). The latest generation of cockpit and mission displays (HUDs, HDDs, HMDs) all utilize ARINC 818–3 as the video protocol of choice due to some specific technical features that are only present in ARINC 818–3. With such a variety of options of video buses and protocols available, how would a system designer decide which protocol(s) to use and how to best integrate them into a low-latency, high-resolution system? Adding to the challenge, the cost of development and certification of equipment is prohibitive in many cases. System designers don't have a clean sheet of paper, but must integrate older, but certified equipment with newer, higher performance hardware. Performance and cost trade-offs are always present, and even many of the newest systems require combining old and new technology to meet the design and cost goals. This work is a follow-on from the paper Interfacing and Testing High-Resolution, Video-Based Avionics and Mission Systems that Use ARINC 818–3 presented at DASC 2023. This paper will discuss the challenge of integrating a variety of video protocols, discuss key features and benefits of each protocol, and explore why ARINC 818–3 is becoming the de-facto standard not only as a display interface, but as a system level bus being used from sensors, to processors, to displays. No other currently available protocol can meet all the technical requirements to serve as the primary video backbone for avionics and mission systems in commercial and military aircraft. The key technical features of different protocols including: SDI, HDMI, Display Port, Ethernet (AFDX, TSN, TTE), and ARINC 818 will be examined. Complex avionics and mission systems architectures need to accommodate multiple different protocols, including both digital and analog. The strengths and weaknesses of each protocol is discussed to help designers understand system level tradeoffs. We examine key system level-design parameters of the different digital video protocols, including: Minimizing sensor to display (or decision) latency, timing precision required for digital displays, flexibility (bandwidths), accommodating both video and data, conversion to/from other protocol standards and pixel types, video concentration (multiple video streams on a single link). Finally, the paper shows why ARINC 818–3 is the best option as the video backbone, and how it can be integrated and interfaced with all the other video protocols and buses. In addition, it points out key design considerations that must be planned at a system level when integrating infrared and optical sensors, video and mission processors, and multiple display types (HDDs, HMDs, HUDs).