Latency in Visionic Systems: Test Methods and Requirements

A visionics device creates a pictorial representation of the external scene for the pilot. The ultimate objective of these systems may be to electronically generate a form of Visual Meteorological Conditions (VMC) to eliminate weather or time-of-day as an operational constraint and provide enhancement over actual visual conditions where “eye-limiting” resolution may be a limiting factor. Empirical evidence has shown that the total system delays or latencies including the imaging sensors and display systems, can critically degrade their utility, usability, and acceptability. Definitions and measurement techniques are offered herein as common test and evaluation methods for latency testing in visionics device applications. Based upon available data, very different latency requirements are indicated based upon the piloting task, the role in which the visionics device is used in this task, and the characteristics of the visionics cockpit display device including its resolution, field-of-regard, and field-of-view. The least stringent latency requirements will involve Head-Up Display (HUD) applications, where the visionics imagery provides situational information as a supplement to symbology guidance and command information. Conversely, the visionics system latency requirement for a large field-of-view Head-Worn Display application, providing a VirtualVMC capability from which the pilot will derive visual guidance, will be the most stringent, having a value as low as 20 msec. 1.0 INTRODUCTION A visionics device provides a pictorial representation of the external scene (i.e., the external environment in which the aircraft is flying), generated by electronics means such as electro-optical sensors, radars and/or a database (synthetic vision). Night vision systems and image intensifiers – two examples of visionic devices have opened the operational capabilities of military organizations such that they can now “own the night.” Synthetic vision and other emerging visionic systems technologies, such as forward looking infrared, and millimeter wave radar, are offering the potential of freeing the pilot from the limitations imposed by restricted outside visual references. Military and commercial operators can now also “own the weather.” The ultimate objective of these systems may be to create a “Virtual-Visual Meteorological Conditions” (Virtual-VMC) capability. This environment is called “virtual”, as it is electronically generated, but it is more accurately described as an augmented reality to eliminate weather or time-of-day as an operational constraint and provide enhancement over actual visual conditions where “eye-limiting” resolution may be a limiting factor. For commercial operations, the potential of Virtual-VMC offers safety and capacity superior to https://ntrs.nasa.gov/search.jsp?R=20050192646 2017-08-15T05:57:22+00:00Z