The DLR 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 for Polar and Marine Research (AWI). During expeditions in the Arctic and the Antarctic, photogrammetric image data particularly of permafrost, sea ice, glaciers and vegetation are acquired.
Polar 5 and 6 research aircraft (left) and DLR MACS-Polar aerial camera system (right)
This collaboration between AWI and DLR was established to develop aerial camera instruments acquiring high quality images for polar application. In a series of flight campaigns the camera takes a range of datasets covering various ground settings. Aspired outcome is introduction of tailored sensor heads, derivation of classification maps, texturized high resolution digital elevation models, change.
The MACS aerial camera is designed to withstand harsh environment like temperatures below -30°C. It has a weight of ~15kg and consists of a computing unit and a sensor head. The sensor head is equipped with matrix array CCD/CMOS/thermal-infrared cameras and is mounted in the fuselage providing free view down. In order to fulfill respective application requirements, sensors, their geometry and spectral ranges are modified. Thus, particular conditions are considered, e.g. flying over brightly reflecting snow, acquisition of highly structured terrain or low flight altitudes without gaps of recorded ground surface. Currently the maximum continuous image acquisition rate is 4 frames per second enabling more than 60% overlap from an altitude of 100 m.
RGB/NIR mapping configuration: footprints on ground from an altitude of 1.000m AGL
In summer 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. awiThe ground pixel resolution was 5 cm to 10 cm in the RGB and 10 cm 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 2019 thaw measurements in northern Alaska were acquired. During this permafrost expedition coastal erosion, subsidence and lake dynamics of the rapidly warming Arctic were observed to better understand and predict permafrost dynamics over the upcoming decades.
As part of MOSAiC expedition in summer 2020 sea ice measurements were conducted in the Fram Strait and north of Svalbard. A thermal-infrared camera was introduced to evaluate additional information from this imager.
In the years 2021-2023 campaigns are planned over permafrost areas in Canada, Alaska and Svalbard, over glaciers in Greenland, and across Northern Atlantic Ocean for sea ice measurements.
Configuration of MACS-Polar aerial camera system in 2020
MACS-Polar was used for these projects:
Images for vegetation and lake analysis (Lake at Trail Valley Creek, Canada, 2018) NIR GSD=15cm (Download) and RGB GSD=9cm (Download)
Bluff caused by ice thaw in permafrost, mapped NIR image with RGB overlay (Download) (Yukon Coast, Canada, 2018)
Texturized 3D point cloud of coast outwash with GSD=8cm (Download) (Yukon Coast, Canada, 2018)
Sea ice thickness overlay based on AWI IceBird data acquired at the same time (Download) (Fram Strait, 2020)
Glacier melt water plume (Kongsvegen glacier, Svalbard, 2020) TIR GSD=50cm (Download) and RGB GSD=10cm (Download)
Melt pond and polar bear paws, RGB GSD=2.5cm (Download)
Image triplet of the year 2020 sensor head (Kongsvegen moraine, Svalbard, 2020) RGB GSD=12cm (Download), NIR GSD=12cm (Download), TIR GSD=60cm (Download)
Thermal infrared mosaic of single flight strip with GSD=60cm (Download) (Kongsvegen moraine, Svalbard, 2020)