The ASPECT aircraft uses a high resolution digital camera to collect visible aerial images.
The camera consists of a Nikon D2X SLR camera body with a fixed focus (infinity) 24mm F1.2 Nikor lens. The camera sensor has 12.5 million pixels (12.2 Mpixels viewable) giving a pixel count of 4288 x 2848 in a 3:2 image ratio.
An effective ground coverage area of 885 x 590 meters is obtained when operated from the standard altitude of 850 meters.
Image ortho-rectification, which corrects for optical distortion and geometric distortion due to the three dimensional differences in the image, is accomplished using an inertial navigation unit (pitch, roll, and heading) coupled with a dedicated 5 Hz global positioning system (GPS). Aircraft altitude above ground is computed using the difference between the indicated GPS altitude and a 30 meter digital elevation model (DEM). Full ortho-rectification is computed using a camera model (lens and focal plane geometric model) and pixel specific elevation geometry derived from the digital elevation model to minimize edge and elevation distortion.
Documented geo-location accuracy is better than 49 meters.
In January 2011, EPA Region 4 initiated a joint ground-based radiological survey effort among the EPA Environmental Response Team (ERT), EPA Region 4, and the Department of Energy (DOE) Remote Sensing Laboratory (RSL) of a portion of the Coronet Superfund Site, near Plant City, Florida. During the ground-based survey effort, an aerial radiological survey was performed over the same area by the EPA Airborne Spectral Photometric Environmental Collection Technology (ASPECT) Program. Funding for the aerial survey was provided through an interagency agreement from the Federal Emergency Management Agency (FEMA), Nuclear Incident Response Team (NIRT) Program.
The ASPECT aircraft used the following flight procedures for data collection on January 19, 2011:
Altitude above the ground level (AGL): 300 feet 500 feet
Target Speed: 100 knots (115 mph)
Line Spacing: 300 feet
One second data collection frequency
A unique feature of the ASPECT remote sensing technologies includes the ability to process spectral data automatically in the aircraft with a full reach back link to the program QA/QC program. As data is generated in the aircraft using the pattern recognition software, a support data package is extracted by the reach back team and independently reviewed as a confirmation to data generated on the aircraft.