How to Build a Simulator – IV – Elements

This post is Part-4 of the “How To Build a Simulator” series. Previously published was the “How To” intro, which includes a summary of the series and a detailed schedule.

The Elements of a Simulator

Flight simulators are complex pieces of technology. They require many components to all work together in unity to ensure everything is functioning properly and is creating a realistic and immersive experience for the trainee. This task is much easier said than done. In today’s edition of the “How to Build a Simulator” series, we will be covering the elements of a flight simulator.


Firstly, we will discuss the most important part of the unit, the host. The host is often referred to as the heart of the simulator as its software simulates all aspects of the vehicle and surrounding environment. It pumps information in and out much as a heart does with blood. This includes the simulated vehicle’s composition, dynamics, state changes, mission data, and interaction with the virtual environment. The host also accepts the mission planning data to determine the trainee’s tasks and it holds the operational flight program (OFP). These responsibilities are critical in the system’s real-time capabilities as it does it all at the required real-time update rates.


Information from the host is sent and received to and from all other groups. This includes the perception group, the perception support group, the instruction group, and various other groups like the power system. Each of these groups has its own set of responsibilities which we will cover in-depth.

The perception group is what the user senses inside of the trainee station. It includes the motion systems, display systems, panels, aural cueing system, and the controls and loading system. Without this group, the users would have no understanding of the virtual world they are training in.

The perception support groups are the software systems that calibrate what is to be displayed through the perception groups. They are the medium between the host and the perception groups.

The instructor group includes the instructor operator station (IOS), the IOS computer system, and the semi-automated forces (SAF). This group is where the instructor monitors and tasks everything the trainee is doing. With this command and control station, the instructor can run or shut down the sim, change mission tasks, and communicate with the trainee.


Now we will delve further into the various components in each category.

Input/Output (IO)

Firstly, we will discuss the input and output system (IO). This system sends and receives digital and analog signals to and from the trainee station or cockpit to determine how the display and motion system will react.

The system of panels includes switches, buttons, instruments, warning lights, indicator lights, and lever positions. Everything in the IO is monitored and translated by the controls and loading computer system for the host to interpret and respond.

Image Generator (IG)

Next is the image generator (IG). Being part of the perception support group, the IG is what holds the databases which contain the entire virtual worlds the aircraft can fly in.

This system sends information like positioning, movement, and environmental factors like the time of day (TOD) or weather to the various displays. Without this system, there would be no training as the trainee would have no idea where the aircraft is or how it is moving.

Display Systems

As previously mentioned, the IG is what supports the display systems. There are multiple displays; the out the window display (OTW), the multi-function display (MFD), the interior cockpit display (ICD), and the head-worn display (HWD). These displays combined give the trainee a realistic view of an operational cockpit in flight.

Aural Cueing and Communications

The aural cueing system is what controls every intentional ambient or mechanical sound inside the simulator. This includes noise from impact as well as sustained, environmental, and vehicle sounds. Verbal sound and communications, however, come from the digital COMM and radio system. The COMM and radio system is crucial in trainee-instructor communication, and training for communication with others. For instance, with this system, the instructor can roleplay as a wingman or air traffic control to ensure the trainee knows how to properly communicate accurate information while keeping their focus on the skies.

Motion System

The motion system is what creates haptic feedback. This is the physical influence one senses while enduring the G-forces and vibrations inside a real aircraft. The motion system is controlled by the motion computer which resides in the perception support group. It is what sends motion, washout, and recovery cues to the motion system.

Motion systems can vary depending on the sim’s purpose and the cost. The cheapest and least immersive is a simple vibration mechanism under the seat of the sim. The middle of the road would be a motion seat that has minor movement and vibration.

The most expensive and immersive would be a motion system platform that has six degrees of freedom (6DOF) and can simulate up to 25% of the vehicle’s real cue magnitude. This percentage is limited by the system movement range, low roll cue, and the necessity of imperceptible washout and recovery cues which brings the system back to its normal position.

The benefits of motion systems include improved realism, muscle memory, and event confirmation through correlated motion cues. However, it should be known, no motion system at all is better for the trainee’s education than an ineffective or delayed motion system.

In unison, these components and groups work together to create an immersive experience and provide the best possible training for the user. Here at AVT Simulation and the AVT Training Center, we understand how each component affects the simulator as a whole. Therefore, we only use the best possible parts that fill the requirements of our customers.

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Initially, Applied Visual Technology Inc., AVT has been developing modeling and simulation expertise through engineering services since 1998. This is due to our founder who has accumulated over 30 years of military MS&T expertise in aviation applications. Nonetheless, everyone at AVT specializes in making old training systems new again and making new ones for less. Consequently, for 20 years AVT has served our Air Force, Army, Navy, and Marine customers by providing the highest quality of service and solutions. Following its inception, AVT’s highly specialized staff of engineers has included some of the top leaders in the simulation industry. With over 20 years of simulation experience, our dedicated team provides specialized solutions for customers with complex problems.