Abstract
As part of Raytheon’s effort to provide innovative calibration capabilities that advance the performance of future earth imaging systems, an on-board Jones source calibrator integrated with vicarious SPecular ARray Calibration (SPARC) is introduced. The Improved Radiometric calibration of land Imaging Systems (IRIS) is a compact full-spectrum calibration system that reduces the size, weight, and power of conventional on-board radiometric sources into a single flat panel format providing high spatial illumination uniformity. Combining both carbon nanotube and LED technology within a Jones source design, IRIS offers a common assembly calibration reference covering the spectral range from 0.4 to 12 μm. On-board calibrator degradation from the effects of launch and lifetime exposure to the space environment impacts performance, making it difficult to maintain absolute knowledge of the sensor radiometry. What has been missing from past on-board lamp calibration systems is an operational capability for establishing and maintaining absolute SI traceability in the solar reflective spectral range after launch and over the sensor lifetime. Introduced in this presentation is a methodology that sustains traceability through a fusion of the on-board IRIS LED reference with Labsphere’s FLARE vicarious system. In this process, the imager collects an on-board calibration source image nearly simultaneously with observations of the sun safely reflected by a FLARE array of convex mirrors on the ground. The process known as IRIS-V provides data for recalibration of the onboard VSWIR system, as needed, in-flight without affecting operational land or coastal image collection. A prototype of the IRIS on-board calibrator and IRIS-V methodology will be described. IRIS is funded by the NASA Earth Science Technology Office (ESTO) through the Sustainable Land Imaging-Technology 2019 (SLIT19) Program.
Integrating On-board and Vicarious Calibration with the Improved Radiometric Calibration of Land Imaging Systems (IRIS)
As part of Raytheon’s effort to provide innovative calibration capabilities that advance the performance of future earth imaging systems, an on-board Jones source calibrator integrated with vicarious SPecular ARray Calibration (SPARC) is introduced. The Improved Radiometric calibration of land Imaging Systems (IRIS) is a compact full-spectrum calibration system that reduces the size, weight, and power of conventional on-board radiometric sources into a single flat panel format providing high spatial illumination uniformity. Combining both carbon nanotube and LED technology within a Jones source design, IRIS offers a common assembly calibration reference covering the spectral range from 0.4 to 12 μm. On-board calibrator degradation from the effects of launch and lifetime exposure to the space environment impacts performance, making it difficult to maintain absolute knowledge of the sensor radiometry. What has been missing from past on-board lamp calibration systems is an operational capability for establishing and maintaining absolute SI traceability in the solar reflective spectral range after launch and over the sensor lifetime. Introduced in this presentation is a methodology that sustains traceability through a fusion of the on-board IRIS LED reference with Labsphere’s FLARE vicarious system. In this process, the imager collects an on-board calibration source image nearly simultaneously with observations of the sun safely reflected by a FLARE array of convex mirrors on the ground. The process known as IRIS-V provides data for recalibration of the onboard VSWIR system, as needed, in-flight without affecting operational land or coastal image collection. A prototype of the IRIS on-board calibrator and IRIS-V methodology will be described. IRIS is funded by the NASA Earth Science Technology Office (ESTO) through the Sustainable Land Imaging-Technology 2019 (SLIT19) Program.