Synthetic Vision System

A Synthetic Vision System (SVS) is a computer-mediated reality system for aerial vehicles, that uses 3D to provide pilots with clear and intuitive means of understanding their flying environment.

Synthetic Vision was developed by NASA and the U.S. Air Force in the late 1970s and 1980s in support of advanced cockpit research, and in 1990s as part of the Aviation Safety Program. Development of the High Speed Transport (HST) fueled NASA research in the 1980s and 1990s. In the early 1980s, the USAF recognized the need to improve cockpit situation awareness to support piloting ever more complex aircraft, and pursued SVS (sometimes called pictorial format avionics) as an integrating technology for both manned and remotely piloted systems. NASA initiated industry involvement in early 2000 with major avionics manufacturers. Researchers like E. Theunissen at Delft University of Technology in the Netherlands contributed greatly to the development of SVS technology.

Synthetic Vision provides situational awareness to the operators by using terrain, obstacle, geo-political, hydrological and other databases. A typical SVS application uses a set of databases stored on board the aircraft, an image generator computer, and a display. Navigation solution is obtained through the use of GPS and Intertial Reference Systems.

Highway In The Sky (HITS), or Path-In-The-Sky, is often used to depict the projected path of the aircraft in perspective view. Pilots acquire instantaneous understanding of the current as well as the future state of the aircraft with respect to the terrain, towers, buildings and other environment features.

NASA also used synthetic vision for Remotely Piloted Vehicles (RPVs), such as the High Maneuvability Aerial Testbed or HiMAT (see Sarrafian, 1984). According to the report by NASA, the aircraft was flown by a pilot in a remote cockpit, and control signals up-linked from the flight controls in the remote cockpit on the ground to the aircraft, and aircraft telemetry downlinked to the remote cockpit displays (see photo). The remote cockpit could be configured with either nose camera video or with a 3D synthetic vision display. SV was also used for simulations of the HiMAT. Sarrafian reports that the test pilots found the visual display to be comparable to output of camera on board the RPV.

Similar research continued in the U.S. military services, and at Universities around the world. In 1995-1996, North Carolina State University flew a 17.5% scale F-18 RPV using Microsoft Flight Simulator to create the 3 dimensional projected terrain environment. However, the recreational uses of Synthetic Vision for RPVs preceded this substantially. For example, in 1980 the Flight Simulator was introduced by Bruce Artwick. But most directly, the RC Aerochopper RPV simulation used synthetic vision to aid aspiring RC helicopter pilots in learning to fly.

According to the "RC Aerochopper Owners Manual" published in 1986 by Ambrosia Microcomputer Products, Inc., the system included joystick flight controls which would connect to an Amiga computer and display. The software included a three-dimensional terrain database for the ground as well as some man-made objects. This database was basic, representing the terrain with relatively small numbers of polygons by today's standards. The program simulated the dynamic three dimensional position and attitude of the aircraft using the terrain database to create a projected 3D perspective display. The realism of this RPV pilot training display was enhanced by allowing the user to adjust the simulated control system delays and other parameters.

After years of research, in 2005 NASA's "Turning Goals Into Reality" program, a synthetic vision system was installed on a Gulfstream V test aircraft as part of the GVSITE project. Much of the experienced gained during that program led directly to the introduction of certified SVS on future aircraft.

The first FAA certified application of a Synthetic Vision System (2009)was available as part of the Gulfstream PlaneView flight deck in the form of the Synthetic Vision - Primary Flight Display (SV-PFD) which replaces the traditional blue-over-brown artificial horizon with the computer generated terrain overlayed with normal PFD symbology. Since then, many newer glass cockpit systems such as the Garmin G1000 and the Rockwell Collins Pro Line Fusion offer synthetic terrain. A number of lower-cost "experimental" class avionics systems also offer synthetic vision systems.