Airborne Spectral Photographic Environmental Collection Technology
ASPECT is the result of the development and integration of sophisticated chemical monitoring equipment onto an airborne platform. The technologies being used are an Infrared (IR) Line Scanner combined with a rapid-scan Fourier Transformation Infrared Spectrometer (FTIR) and the latest generation in processing portable computers. This technology application uses passive infrared energy (radiance) to measure the energy absorbed and released by chemicals in the atmosphere. The system is capable of accurately detecting and quantifying concentrations of specific chemicals in air at levels that present human health threats. The capabilities of the FTIR sensors limited them to stationery platforms in the past. Advances in the sensitivity of the IR instruments, improved processing methods, increased computer processor speeds and storage permit technology of this type to be operated from a mobile, airborne platform.
The ASPECT system can be deployed to most release incidents occurring in the lower 48 states within ten hours. Voice and data communication capabilities of the system will allow for near real time data to be transmitted to incident commanders at the scene. This gives the decision-makers on the ground quantified, quality data in a digital graphics format which otherwise would take days to compile. Evacuation and shelter in place operations could be reduced by hours on smaller releases, up to days in larger incidents. This would provide for significant cost savings to the local governments and affected businesses. The products generated by the System would also significantly improve the evaluation and communication of risks to the public.
The infrared scanner is an infrared line scanner (IRLS), which is a modified Raytheon TI Systems RS-800 system, it has optimized optical filters to detect specific gas species. Detector channels cover both the 3-5 and 8-12 micron atmospheric spectral windows. The line scanner operates a spinning prism at 60 cycles, this coupled with the movement of the aircraft provides an infrared image capable of "mapping" the chemical plume. At an aircraft speed of 100 kts (data collection speed), the scanner will provide pixel sizes of approximately 2 square feet at an above ground altitude of 2000 feet. The total swath of the image is about a half a mile.
The FTIR is a Bomem system capable of data collection for the same atmospheric spectral windows as the IRLS. The FTIR scans at about 80 hertz and provides a pixel collection interval every 5 to 8 feet.
Additional equipment incorporated into the ASPECT System includes a high resolution digital still camera and a digital video camera. The digital still camera has the capability to provide digital aerial photographs at a resolution of 4.5 million pixels. The digital video camera provides for the capability to transmit video clips to the incident commanders on the ground.
Transmission of data from the aircraft to the ground is through a wireless ether-net link operating at 11 megabits/second. A self-contained down-link package is provided to the incident commander by either direct hand over at a nearby airport or via parachute deployment. Once the incident commander has custody of the down-link package data from the aircraft can be viewed by the ground personnel.
The ASPECT System is installed in an AeroCommander 680, a twin engine aircraft capable of cruising speeds of 190 knots and the ability to loiter over the incident collecting data for up to six hours. The aircraft is currently based in Texas. The aircraft and its pilots are under contract with the US EPA to provide support to the EPA and local responders in the case of an atmospheric release of chemicals. Any EPA OSC can directly order the deployment of the system.