Binaural Radar Warning Receiver for SL Binaural audio recordings provide a natural 3D sensation of acoustic sources. For SL, a binaural Radar Warning Receiver (bRWR) should be made available as innovative feature. The audible warning tone should represent a virtual position of the opponent in the perception of the pilot by simulation of natural 3D sounds. The pilot should be able to „hear“ the direction of the threat and – by the pitch and the pattern of the warning tone – estimate the distance and consequently the urgency of the warning. Instead of developing the very complex software and algorythms (including use of HRTF libraries) for on-the-spot generation of the desired warning tones, a set of pre-recorded binaural wave files will be triggered by a more simplified calculation based on the already available parameters of the simulation.

Virtual position of Binaural Warning Tone (BWT) calculated from Own position in relation to opponent position (angle & range) Own aircraft orientation in space for correction of the audible representation Given opponents max radar range as discriminator for either activate the warning or not. BWT selected from 88 pre-recorded binaural wave files: 6 main directions in 3 planes (x,y,z to -y,-x,-z) 8 x 45° vectors in each plane 8 x 45° vectors between planes 4 different ranges (0 - 3 (very far, far, close, very close)) represented by 4 different frequencies (low pitch to high pitch, higher numbers represent higher pitch) Each binaural wave file represents one of the four distances and one of the 22 possible directions/vectors of an opponent radar, giving a total of 88 different warning indications.

Y - Y Z - Z X - X Overview X-Y-Z Orientation

Y - Y Z - Z X - X 0X1Y1Z2R „Opponent 12 o‘clock high, far“ Vector/range calculation in positive Y/Z plane

Y - Y Z - Z X - X 0X-1Y-1Z2R „Opponent 6 o‘clock low, far“ Vector/range calculation in negative Y/Z plane

Y - Y Z - Z X - X 1X-1Y-1Z1R „Opponent 4 o‘clock low, close“ Vector/range calculation in a sector between planes

0X0Y0Z0ROwn aircraft position. Not calculated 1X0Y0Z1R … 0X1Y0Z1R … 0X0X1Z1R … -1X0Y0Z1R … 0X-1Y0Z1R … 0X0X-1Z1R … -1X-1Y-1Z3R Binaural wave file syntax Value X- Axis (1 or -1) Value Y- Axis (1 or -1) Value Z- Axis (1 or -1) Value Range (0-3)

Binaural Wave Tone File Selection For vector calculation, only the 22 defined vectors will be considered. The calculated angle (X,Y,Z) will be rounded to match the closest value of the own data table (X,Y,Z). The calculated distance between the own aircraft and the opponent will be used for selection of the tone pitch. Closer ranges will trigger wave files with higher pitch.