Recent years have witnessed a steady increase in the number of search and rescue missions flown by RAF helicopter crews. Central to the success of these missions is the role played by the helicopter voice marshalling aircrew who verbally relay important flight commands to the pilot in order to guarantee the accuracy and safety of the aircraft’s approach. Across the spectrum of RAF activities, voice marshalling (“VM”) plays a vital role, not only in search and rescue missions but also in the delivery of military and survival resources to remote areas, often confined by natural features.

 

In late 2001 the RAF commissioned VP Defence, a subsidiary of The Virtalis Group, to develop a Virtual Reality(VR) Voice Marshalling simulator in order to foster improved training techniques and to minimise the need for costly “remedial” training, both on the ground and in the air.

 The main elements of the delivered simulators include:

VM student’s workstation.

A wooden structure representing the rear door are a of the Griffin helicopter provides a suitable framework for use in conjunction with the immersive VR equipment to provide aircrew students with handholds and a standard RAF harness.

VM trainer’s workstation.

A single Windows PC with dual graphics cards drives both the real-time rendering engine for the VM student (duplicating the student’s HMD view on one of two trainer displays) and the scenario control interface used by the trainer to set up, run and replay/debrief scenarios.

Virtual seascape scenarios

Sea states 1 through to 6 are available and, for both the sea and land environments, variable levels of rain and fog can be selected, together with variable lighting conditions. 

Our 2005 upgrade included the fantastically realistic sea you can see in the picture opposite.  The sea-scape animation system uses a statistical algorithm to generate realistic wave geometry in real-time, from which we derive the full range of sea states. For the actual rendering of the sea surface, we combine hardware displacement mapping with per-pixel lighting, full-scene reflection/refraction, and dynamic foam generation to replicate the textural complexity of an ocean surface. To manage the workload of the graphics card, we use a bespoke level-of-detail solution to give a smooth and seamless fall-off of detail from the viewer to the horizon – this also allows us to provide an infinite expanse of ocean.

Target objects, from survival dinghies to a motor launch, even a disabled submarine, can be positioned within the virtual seascape by the VM trainer.

Virtual landscape scenarios

A 12km² area around the RAF Shawbury site was constructed in detail with a further 30km² surround in lesser detail. Digital terrain elevation data and aerial photographs were used to generate the base topography whilst landscape features, such as copses, dead trees, small lakes and ponds, electricity/radar pylons, hangars and other man-made features are included to ensure sufficient visual details to support a range of VM activities. Other target objects, from military trucks to barrels can be positioned within the virtual landscape by the VM trainer.

The second phase of the project, delivered in 2003, involved creating a coastal flying module in a virtual island that is half mystical and half recognisably Anglesey, with its 200 foot high cliffs. It also enables training with an under slung load, challenging rear crew to talk the pilot through a pick up or drop in a confined area packed with obstacles.

Like the other Virtalis/VP Defence training systems, the VR VM trainer employs the Instructor’s Scenario Control Interface. It is a user friendly, multi window, point-and-click display subsystem that allows instructors to pre-program, run, save and replay scenarios. The instructor also controls the helicopter with a joystick, responding to the VM commands given. For debrief, the system has a virtual play back mode that can store 20-minute missions.

 These include:

• Own aircraft course and position
• Position of other craft and targets
• Exact environmental conditions, including continuous sea-state
• Audio recordings of student voice commands
• Exercise Controller replies and background sounds