Pixel-based airborne hyperspectral sensing technique for search-and-rescue of the missing RMAF NURI helicopter in Genting-Sempah, Malaysia

摘要

Purpose — The purpose of this paper is to develop and describe a pixel-based airbornehyperspectral remote sensing system approach for searching for missing and lost RMAFaircraft, especially the NURI helicopter that crashed in Genting-Sempah, Malaysia on Friday 13July 2007, ten minutes after leaving the RMAF 10th Squadron based in Sg. Besi Camp, Selangor,Malaysia. It was reported found crashed with all six air force crew onboard killed, four days lateron 17 July 2007 at 13.25 hours 5 km North-west of Genting-Sempah-Karak-Highway. Design/methodology/approach — The objective is achieved by exploring the use of a veryhigh 1 m2 spatial resolution (pixel-based) airborne hyperspectral imaging system near real-timedata processing within two hours after landing. The UPM-Aeroscan's AISA is a state-of-the-artaircraft mounted commercial hyperspectral sensor operated for SAR development application byForest Geospatial Information and Survey Lab (FGISL)/Aeroscan Precision (M) Sdn Bhd. inBlock C3, UPM-MTDC Tech Centre, Lebuh Silikon, Universiti Putra Malaysia. It is designed toprovide a near real time, frequent, repetitive, accurate and reliable pushbroom instrument thatacquires images in hundreds of registered, contiguous narrow spectral band passes such that foreach element it is possible to derive a complete reflectance spectrum between the tree crowns, adamaged or slashed tree canopy and an anomaly especially metal like foreign object thatpenetrates into the tree crowns of a dense forest. Using an advanced Spectral Angle Mapper(SAM) digital analysis and two archives spectral signatures of flying and "parked" NURIhelicopters, in addition to ground supporting data from the civilian eye-witnesses, spectralmatching of images is applied to identify and map the missing helicopter. Findings — Despite the bad weather hampering the search and air surveillance-to-groundverifications, the NURI helicopter was reported found crashed with all six air force crew onboardkilled, four days later based on the GPS suspected locations analysed and mapped from theUPM-APSB's AISA airborne hyperspectral sensor data. The GPS locations given by the imagewere, however, not accurate for ground verifications since an old military topographical mapwere used. The GPS locations from the airborne image was transferred on to a Google Earthimage in the Operations Room but, for ground verifications, a different set of referencetopographical maps were used. However, the suspected search target sites were not that faraway from the actual sighted RMAF NURI helicopter wreckage. Originality/value — The value and contribution of this research are the successful applicationof operating a pixel-based airborne hyperspectral sensor to locate missing military helicopters inSAR. It is expected that the UPM-APSB's AISA airborne hyperspectral sensor can be of furtheruse in future SAR for missing civilian helicopters or commercial aircraft.