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

Abstract

PurposeThe purpose of this paper is to develop and describe a pixel‐based airborne hyperspectral remote sensing system approach for searching for missing and lost RMAF aircraft, especially the NURI helicopter that crashed in Genting‐Sempah, Malaysia on Friday 13 July 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 later on 17 July 2007 at 13.25 hours 5 km North‐west of Genting‐Sempah‐Karak‐Highway.Design/methodology/approachThe objective is achieved by exploring the use of a very high 1 m2 spatial resolution (pixel‐based) airborne hyperspectral imaging system near real‐time data processing within two hours after landing. The UPM‐Aeroscan's AISA is a state‐of‐the‐art aircraft mounted commercial hyperspectral sensor operated for SAR development application by Forest Geospatial Information and Survey Lab (FGISL)/Aeroscan Precision (M) Sdn Bhd. in Block C3, UPM‐MTDC Tech Centre, Lebuh Silikon, Universiti Putra Malaysia. It is designed to provide a near real time, frequent, repetitive, accurate and reliable pushbroom instrument that acquires images in hundreds of registered, contiguous narrow spectral band passes such that for each element it is possible to derive a complete reflectance spectrum between the tree crowns, a damaged or slashed tree canopy and an anomaly especially metal like foreign object that penetrates 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” NURI helicopters, in addition to ground supporting data from the civilian eye‐witnesses, spectral matching of images is applied to identify and map the missing helicopter.FindingsDespite the bad weather hampering the search and air surveillance‐to‐ground verifications, the NURI helicopter was reported found crashed with all six air force crew onboard killed, four days later based on the GPS suspected locations analysed and mapped from the UPM‐APSB's AISA airborne hyperspectral sensor data. The GPS locations given by the image were, however, not accurate for ground verifications since an old military topographical map were used. The GPS locations from the airborne image was transferred on to a Google Earth image in the Operations Room but, for ground verifications, a different set of reference topographical maps were used. However, the suspected search target sites were not that far away from the actual sighted RMAF NURI helicopter wreckage.Originality/valueThe value and contribution of this research are the successful application of operating a pixel‐based airborne hyperspectral sensor to locate missing military helicopters in SAR. It is expected that the UPM‐APSB's AISA airborne hyperspectral sensor can be of further use in future SAR for missing civilian helicopters or commercial aircraft.