Flight simulators range in price from free to tens of millions of dollars and in purpose from pure entertainment to serious business — such as learning to fly multi-million-dollar aircraft without crashing them in real life and getting anyone killed. Military and commercial pilots spend thousands of hours in simulators learning both routine operations and how to deal with emergency situations. They can become fully proficient through immersive training in these virtual environments. The U.S. Army, Air Force, Navy and Marines all use flight simulators to train pilots to fly in battle, recover in an emergency, and coordinate air support with ground operations. To do this, they use hardware and software developed both by military agencies and by commercial military contractors.
In high-end flight simulators, the trainee steps into a life-size replica of a cockpit, whereas others consist of several monitors that cover the trainee’s field of view, or, at the lowest end, everything is crammed onto a single monitor. All flight simulators, however, are designed to replicate as closely as possible the layout and controls of a real aircraft. (Ironically, the $120 Microsoft Flight Simulator Premium Deluxe Edition lets you fly 35 different planes, while flight simulators that cost tens of millions of dollars are limited to a few models because they have to physically replicate the cockpit layout, which varies from aircraft to aircraft. Some training centers invest in multiple simulators, while others privilege convenience over accuracy and use a single simulator model.)
Most professional flight simulators sit on top of either an electronically-controlled motion base or a hydraulic lift system that rotates the replica cockpit in three dimensions in reaction to both user input and simulated events. This provides trainees with haptic feedback, in other words, feedback they can feel. (Another example of a device that provides haptic feedback is a joystick with force feedback.)
Like when learning to sail offshore or to survive in the wilderness, a large component of any pilot training program is navigation. For flight simulators, this involves detailed aeronautical charts, huge amounts of Earth observation imagery including thousands of airports, and faithful replicas of several cockpit navigation instruments. While aviation programs provide standard training to ensure pilots can handle situations ranging from enemy fighters to bird strikes to engine failure, they may overlook the importance of duplicating actual cockpit instruments rather than relying on facsimile ones.
Simulating GNSS signals
This is where GNSS simulators come into play. They make it possible “to simulate the actual GPS signal required by the cockpit navigation instruments,” according to a case study by Orolia.
This approach, the company points out, offers advantages to both the trainees who use flight simulators and the engineers who develop them. For a trainee, “the advantage is that he is trained using the identical instruments as those in the actual airplane […] providing the same feedback as a real-world experience.” For an engineer developing a flight simulator, GNSS simulators make it possible to “design more effective flight simulation programs without compromising quality.”
Furthermore, “using real navigation instruments may […] reveal unexpected behavior from the instrument, which helps the pilot to be prepared for this possibility. If any conditions involving the plane dynamics are not properly handled by the navigation unit, the pilot can obtain actual feedback from real navigation instruments, which could differ from feedback provided by a facsimile instrument.”
Hardware-in-the-loop (HWIL) techniques enable Orolia to integrate its simulator in a flight simulator to reproduce the GPS/GNSS dynamics for the airplane in real time. “Because the pilot steers the aircraft in real time, the GPS simulator must also simulate GPS signals in real time, forming an HWIL integration,” the company said. “This integration enables the flight simulator to integrate the actual navigation unit to provide a very realistic environment for the trainee.”
Racelogic, another manufacturer of GNSS simulators, is launching a new RealTime LabSat that can connect to Microsoft Flight Simulator, including the new 2020 version. “This will create a live GNSS RF feed that accurately follows the trajectory in the simulator, enabling the testing of any GNSS device as though it were being flown on the aircraft,” said Julian Thomas, the company’s managing director. “To help make this a cost-effective solution, we have recently optimized our SatGen signal simulation software so that a real-time simulation such as this can be carried out on an entry-level PC with a full constellation of simulated satellites.”
The GNSS and flight simulation industries overlap even further. For example, Garmin, which manufactures consumer GPS receivers, makes the avionics used in some professional flight simulators.
Simulator demand on the rise
The utility of simulators is not limited to training human pilots and drivers. The demand for simulation is being sharply increased by the development of autonomous vehicles of every kind — from self-driving cars to unmanned aerial vehicles (UAV), from bathymetric vessels to urban air mobility (UAM) aircraft.
For example, manufacturers of self-driving cars need to simulate driving millions of miles, in all kinds of traffic and weather conditions, to perfect their vehicles’ algorithms. The result of all these simulations is better trained human and robotic pilots and drivers prepared for real situations, superior mission readiness, and maximum safety for both military and civilian operations on land, at sea and in the air.
Feature image: In a simulated G1000 NXi integrated flight deck for a King Air 350, a pilot refers to the Garmin Pilot app, used as a supplement during flight. (Photo: Garmin)
