Matt McKeever Jonathan Baker UAV Design Team 11/16/2006 http://www.au.af.mil/au/2025/volume3/chap08/img00003.gif
Air Data Computer Inputs: Outputs: Specifications: Pneumatic pitot/static data Electronic signal from outside temperature probe Outputs: Mach Indicated airspeed True airspeed Vertical speed Static air temperature Total air temperature Uncorrected pressure altitude Barometric corrected altitude Specifications: Power: 28 V DC, 8 W Weight: 1.5 - 6.0 lb http://www.sandiaaerospace.com/
Turbofan Engine Management Input Fan inlet temperature and pressure Fan rotor speed (N1) High-pressure compressor inlet temperature and pressure Core rotor speed (N2) High-pressure compressor exit temperature and static pressure Low-pressure turbine blade temperature Bypass duct static pressure at the mixing plane Low-pressure turbine exit temperature and static pressure Results Good running engine Engine pressure ratio and other data to pilot http://www.wikipedia.org/
Multi-Spectral Data Fusion Energy of spectral features contained in low frequencies Energy of spatial features (edges) contained in high frequencies Multiple narrow spectral sensors provide a better spectral resolution www.airsurvey.com
Missile Warning Sensors Multi-Imaging Multispectral (MIMS) Two color IR sensor Eliminates background clutter by using separate IR bands Weight: under 6.5 lb Power: 28 VDC, 20-50 W http://www.dsd.es.northropgrumman.com/DSD-Brochures/dircm/mims.pdf
Navigation Redundant Inertial Reference Systems Uses a ring laser gyro to sense angular rate about the roll, pitch, and yaw axes Uses accelerometers to measure linear acceleration in the roll, pitch, and yaw directions Uses magnetometer to sense direction Generally 2-3 on board Cross-checked with one another for accuracy If available, compared to GPS Power: 28 V DC, 2-60 W Weight: 2-30 lb Flight Management Computer Does actual cross-checking for IRS’s and GPS Uses input from Air Data Computer, IRS, GPS, and Enhanced Ground Proximity Warning System to navigate http://www.ngnavsys.com
Stereoscopic Imaging Two cameras spaced apart and focused at the same object Gives a 3D effect when the images are combined Can be used to estimate height of vegetation or structures Ratio of camera-to-camera distance and camera-to-subject distance needs to be greater than 1/400 to retain stereoscopic effects. Greater than 1/80 is ideal http://www.khai.edu/eng/niipfm/images/strizhm-pic.jpg
Terrain Collision Avoidance Enhanced Ground Proximity Warning System Sends warning if projected path will collide with the terrain Accesses database of terrain Incorporates sink rate Altitude is inputted Radar altimeter Indicates distance from ground to aircraft Important in landing Landing Warnings If LG and/or flaps are not down, and radar altimeter or air data computer senses below 2500 ft, pilot is warned of the situation If sink rate is too high and radar altimeter senses a very low altitude, pilot is warned they are sinking too fast http://www.stickeen.com/
Sensor Fusion and Design Teams AIAA: Flight and engine computers will most likely be required Possible integration of anti-missile technologies Majority of sensors are not large or heavy HPA: No real need for sensor fusion, or sensors in general Must be able to shave as much weight as possible UAV: Platform is designed and built around advanced sensor technologies Space and payload are very limited A stable aircraft is desired for aerial photography
Conclusions Adds reliability and safety to the aviation community Adds new and exciting reconnaissance and surveillance capabilities Provides redundancy and accuracy http://www.softwaretechnews.com/stn4-1/afrlsensors.html
References http://digilander.libero.it/andreatheone/irs.htm http://ieeexplore.ieee.org/iel5/8352/26315/01167127.pdf http://ieeexplore.ieee.org/iel5/9126/29027/01308901.pdf http://www.dsd.es.northropgrumman.com/DSD-Brochures/dircm/mims.pdf http://www.gpsworld.com/gpsworld/article/articleDetail.jsp?id=352808&searchString=crossbow http://www.nsd.es.northropgrumman.com/Automated/products/LTN-101E-GNADIRU.html