Emissions Detection And Reporting, commonly known as EDAR, is a state-of-the-art remote sensing technology invented and developed by Hager Environmental & Atmospheric Technologies (HEAT).
This technology is an eye-safe laser-based technology capable of remotely detecting and measuring infrared absorption of environmentally critical gases coming out of a moving vehicle.
No Calibration Required
The EDAR device does not require calibration to guarantee proper function. Due to the absolute nature of EDAR’s spectroscopic measurements, it can measure the targeted pollutants without explicit field calibration and remain within standard specifications. EDAR uses the DiAL method, a well-known method used in satellite technologies where direct calibrations are not possible. The DiAL method uses lasers locked into a particular wavelength and with narrow bandwidths to differentiate between extremely narrow absorption features. The lasers continuously subtract out the background radiation, changes in ambient conditions, and instrument noise.
Unlike competing technologies that use a much less reliable and imprecise method of non-laser light sources - the non-dispersive infrared (NDIR) technologies, EDAR does not require calibration. NDIR technologies require calibration due to changes in ambient conditions, instrument drift, and noise. In a blind study performed by ERG and USEPA, the EDAR system proved to have no drift and continuously collects accurate data without any need for calibration. Therefore, EDAR operates 24 hours a day, seven days a week, unmanned and without calibration.
What is Remote Sensing?
Remote sensing is a powerful tool for emissions testing. Using the principles of inelastic scattering of infrared to ultraviolet light, it can detect the presence, relative concentrations, and quantities of specific gaseous compounds in a gaseous plume. Hager Environmental & Atmospheric Technologies (HEAT) used these principles to develop the innovative technology known as Emissions Detection And Reporting (EDAR).
EDAR utilizes a LiDAR system similar to existing satellite platforms such as the Active Sensing of CO2 over Nights, Days, and Seasons, or ASCENDS. Lessons learned from the research and development of such space-based platforms have been applied at a distance of 10 meters as opposed to 690,000 meters (Sun-synchronous orbit). EDAR measures total column abundances in the same method as active remote sensing satellite platforms. Retrievals are more sensitive, more accurate, and more reliable using lasers instead of a broadband system. Lasers simultaneously measure CO2, CO, NO, NO2, NOx, HC, and PM. EDAR scans the entire exhaust plume to retrieve absolute amounts of these gases and to find the optically thickest part of the plume to maximize Signal-to-Noise Ratio (SNR) for relative amount retrievals.
ICCT and the TRUE Initiative made a great explainer video that can be viewed below: