The Institute of Optical Sensor Systems is contributing a special version of its scientific Modular Aerial Camera System (MACS) for the research aircrafts Polar 5 and Polar 6 which are operated by the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI). Collecting fundamental data in polar region about permafrost, sea ice, glaciers, vegetation etc., these aircraft undertake expeditions in polar region like the Arctic and Antarctic.
Polar 5 and 6 research aircrafts by AWI (left) and MACS-Polar aerial camera system by DLR (right)
The objective of this collaboration between AWI and DLR is to develop an applicable aerial camera instrument for high quality imagery under challenging conditions. In a series of AWI flight expeditions the camera will cover various ground settings to acquire manifold datasets. Aspired outcome is the knowledge about the instrument itself, derivation of up-to-date classification maps, texturized high resolution digital elevation models, change detection analysis (e.g. land mass loss and vegetation index) and highly-overlapping images for AI approaches.
The MACS instrument is designed to withstand harsh environment like temperatures less than -30°C. It has a weight of 15kg and consists of a computing unit and a sensor head. The sensor head can be equipped with matrix array CCD/CMOS/bolometer cameras and is mounted in the fuselage providing free view downward. The maximum continuous image acquisition rate is 4 frames per second. In accordance with the respective aim of the project, sensors, sensor geometry and radiometry parameters are modified to consider particular conditions like low flight altitudes less than 60m without gaps of recorded ground surface, flying over brightly reflecting snow, or acquisition of highly structured terrain.
RGB/NIR mapping configuration: footprints on ground from an altitude of 1.000m AGL
In 2018 MACS-Polar had its debut to acquire high resolution aerial images in northwestern Canada. During a four weeks permafrost campaign covering Herschel Island, Trail Valley Creek and Yukon Coast approximately 200.000 images in the visual (RGB) and near-infrared (NIR) spectrum were acquired. The ground pixel resolution is 5 to 10 cm in the RGB and 10 to 15 cm in the NIR images. From a flight altitude of 1.000 m above ground level this yields to a point density of ca. 120 pixels per m² in the RGB and an along-track image overlap of 93%.
In summer 2019 thaw measurements in northern Alaska are acquired. In this three weeks permafrost expedition coastal erosion, subsidence and lake dynamics of the rapidly warming Arctic are observed to better understand and predict permafrost dynamics over the upcoming decades. Until 2021 campaigns are planned to glaciers in Greenland and through Northern Atlantic Ocean for sea ice measurements.
MACS-Polar is scheduled to support following research projects in 2019:
ID of Polar 5 is C-GAWI and ID of Polar 6 is C-GHGF
MACS-Polar was already used for these projects:
Images for vegetation and lake analysis: NIR GSD=15cm and RGB GSD=9cm
(Lake at Trail Valley Creek, Canada, 2018)
Bluff caused by ice thaw in permafrost, mapped NIR image with RGB overlay
(Yukon Coast, Canada, 2018)
Texturized 3D pointcloud of coast outwash, GSD=8cm
(Yukon Coast, Canada, 2018)