Visualisation Environments

Flight simulation has been a vitally important industry for its utility as a training tool for the airline industry and the military, as a research tool in academia and as a gaming environment for enthusiasts. Several different companies have released bespoke flight simulation software, such as Microsoft (Microsoft Flight Simulator series), Laminar Research (X-Plane series), and Flight Gear. The complexities of these visualisation environments has developed to a point where the terrain modelling includes real world road networks, ground vehicles, real world buildings, airports and aviation traffic.

3.3.1.1 XPlane vs. MSFSX

At the outset of the project the selection of appropriate software was key. X-Plane 9 (Later upgraded to 10) was already pre-installed onto the Avionics Testbed Facility (ATF) Simulator, however, another and arguably the largest PC format flight simulator on the market is Microsoft Flight Simulator X (MSFSX). These two simulators were selected as main contenders due to their leading positions in the simulation software market. A comparison between the two was key to making an informed decision between the software. The following areas needed consideration before making a decision as to which software was better suited to the application in this body of research.

• Realism

• Data Accessibility and Control

• Software Updates and Effects

It was important to identify a strong visualisation tool that would be maintainable for the longevity of the project and the facility, as there are significant learning overheads associated with the familiarisation of coding practices for each piece of software. Should a function be needed later in the development of the facility that was not properly identified early in the project there could have been serious delays in the project. The three main areas for consideration will be discussed in the next few sections:

3.3.1.1.1 Realism

The two simulation suites offer different levels of both visual and physical realism, where visual realism is the degree to which the simulation represents the real world in terms of graphics and physical realism is the degree to which the simulation represents the aerodynamics and flight characteristics of the aircraft being flown.

The visual representation of the graphics capabilities of both X-Plane 10 and MS- FSX are high. What is particularly relevant is that X-Plane 10 has accurate road map data for the UK, and indeed almost the entire globe, as it uses OSM as its data source [127]. This was deemed particularly useful as the scope of this research project included targeting moving vehicles. Further, as the Remote Operator Terminal would be developed using map data from the same source, it would make integration simpler.

In terms of physical realism X-Plane 10 also out-performs MSFSX in how it calculates the dynamics of aircraft within the simulation. Whilst MSFSX uses the industry stan- dard Total Forces and Moments Method, X-Plane uses Blade Element Theory which slices each aerodynamic surface into several sections which results in an increase in accuracy by approximately 20% [128]. Blade Element Theory is typically used to find the forces on helicopter rotors [129] and has been modified to analyse the aerodynamic surfaces of aircraft in X-Plane [130]. Whilst the weapon systems are represented by external MATLAB models, the release aircraft were not modelled and default aircraft from the simulation software were used.

3.3.1.1.2 Data Access and Control

X-Plane and MSFSX offer a Software Development Kit (SDK). A SDK allows for additional feature implementation through writing code that can be called from the simulation software in its internal runtime. The ability to develop within the SDKs is still limited by the scope of the SDK, and the areas that plug-in software can be developed must be considered in relation to the custom functionality that might want to be added to the simulator.

MSFSX is split into four core categories [131]:

• Core Utilities Kit

• Environment Kit

• Mission Creation Kit

X-Plane is split into eight core categories [132]: • Data Access • Processing • User Interface • Graphics • Camera Control

• Navigation and the Flight Management Computer (FMC)

• Aircraft

• Widgets

Whilst both software applications offer considerable customisation and development tools, one critical element not provided by MSFSX is Weaponry. MSFSX is tailored towards civil flight simulation and does not include a system for weapons. X-Plane 10 has a range of weapon types implemented into the simulation from guided air-to-air missiles, rockets and bombs. The limits on the X-Plane built-in weapons system is its inability to guide weapons to ground targets. The guidance of air-to-surface weapons has not been developed in X-Plane.

3.3.1.1.3 Software Updates and Effects

Considerations of the effect of version updates on the development of plugin code were also made when deciding which simulation environment to choose. X-Plane 10 (released in 2012) has full backwards compatibility with plugins generated for X-Plane 9.70. The plugins built for Microsoft Flight Simulator 9 (2004) are not compatible with MSFSX, nor are they with Microsoft’s latest Flight Simulation software, “Microsoft Flight”. This makes the longevity of software plugins in the Microsoft Flight Simulator franchise through future releases very difficult, and will require re-development of plugins with each new release.

3.3.1.1.4 Overall Considerations

The final decision was made to use X-Plane as a visualisation environment for this body of research. There is a larger scope for data access and control through the use of plugins. There is more longevity of plugin development with backwards compatibility. X-Plane has a far more realistic flight model dynamics for piloted aircraft, and has comparable graphical fidelity with the inclusion of OpenStreetMap road networks.

3.3.2 MATLAB Weapon Simulation Integration with X-Plane Plug-