Optical Methodes to Calculate Relative Distances and Approach Speed during Refuelling Manoeuvres

Francisca Coll Herrero, HO Flight Test Analysis Tools Department, Airbus Defense and Space, Getafe-Madrid, Spain
Israel Lopez Herreros, Flight Test Analysis Tools, Airbus Defense and Space, Getafe-Madrid, Spain

Abstract

In hose & drogue contact tests, the approach speed of the receiver aircraft must be within the limits specified in the normative and are useful information to analysis the refueling maneuvers.

Airbus Defense and Space (Airbus DS) is working on a new in-flight measurement automatic determination of approach speed, offering a non-intrusive low-cost alternative to traditional GPSs.

Approach speed is calculated using powerful techniques of automatic image recognition, and the speed deriving the shift with a digital filter.

The advantages of this new methodology over traditional methods are the cheaper and faster FTI (Flight Test Instrumentation) installation and calibration process, high flexibility and straightforward refurbishing for customer delivery makes possible to use this technique on customer aircraft (non-dedicated FT prototypes).
This method is currently used on A330 MRTT (FSTA, RAAF, UAE), and A400M as a tanker.

The measuring equipment consists in:

1. One video-camera synchronized with flight test parameters with sufficient field of view to cover the refueling maneuver. On A330 MRTT, a new camera installation is not required, since the own cameras of the BEVS system are used.
2. Knowing reference distance like receptor wingspan.
3. FOLLOWME Tool has been developed by Airbus DS and it is based on image recognition techniques and photogrammetry calculations to obtain approach speeds. This tool works either in real time mode acquiring the video received by telemetry or in offline mode.

FOLLOWME TOOL has a potential for future In-Flight Refueling Operational
procedures, paving the way for future applications such as:

• Computer-assisted guidance for In-Flight refueling Operations
• Fully automated In-Flight refueling
• Unmanned Vehicles In-Flight refueling
• Improved computer-aided In-Flight training