The Hyspex VNIR 1600 provides high quality hyperspectral imaging capability from the ECO-Dimona. The VNIR 1600 is a pushbroom imaging system with 1600 spatial pixels across track and 160 contiguous spectral channels across the visible-near infrared part of the spectrum. Coupled with ability of the ECO-Dimona to operate at low flying speeds and heights this provides an exceptional tool for high resolution hyperspectral imaging over wide spatial areas (i.e. 10s-100s sq. km per hour). The VNIR band is particularly useful for studying vegetation and its role in the global carbon cycle, as well as other ecosystem services. General Specifications At normal sampling speeds (40 m/s (80 kts)), the highest resolution obtainable will be in the order of 0.3 m (across track) x 0.6 m (along track), as determined by the sensor acquisition rates. Use of the 34 degree FOV expander will allow us to make such acquisitions from heights as low as 800m above surface, significantly reducing atmospheric effects. Image coverage rate at this resolution is around 70 sq km/hr, which can be increased by operating from higher altitudes at slightly lower resolutions. ECO-Dimona Installation The main sensor head is mounted in the ECO-Dimona's left hand under-wing pod ('Pod 1'), co-aligned with the RT3003 INS/DGPS, camera and laser altimeter. The supporting PC is mounted on a removable rack in the rear cabin. The main sensor head, weighing approximately 5 kg is mounted in a dedicated bay within the Navigation-Alignment System mounting block. The sensor head is rigidly co-aligned with the RT3003 INS/DGPS system. Also co-aligned are the EOS 5D MkII camera of the CAM system and the Riegl LD90-3300HR laser altimeter of the Navigation-Alignment System. The optic is provided with a clear view downard via an unglazed port in the underside of the pod shell beneath. Power and signal is provided through the dedicated Camerlink cable routed from the Hyspex PC in the rear cabin. The Hyspex PC is mounted to a removable shelf that is installed on the rear cabin rails when required. The Cameralink cable to the snsor head is connected to the PC via the provided breakout connector. Irradiance System We have developed a custom built irradiance measurement system to support the Hypsex imager. The system is built around a USB2000 non-imaging spectrometer with a cosine receptor fore-optic mounted through the roof of the rear cabin. The USB2000 spectrometer is housed within a small temperature controlled enclosure to ensure that the temperature of the diffraction grating and electronics are maintained throughout flight, irrespective of changes in ambient and cabin temperature. The enclosure and its control box are mounted alongside the Hypsex system's controlling PC in the rear cabin. Custom software running on the Hyspex PC controls and logs the USB2000 data, and can be slaved to the Hyspex system's acquisition controls to reduce workload. The software automatically optimises the settings of the spectrometer, monitors the output for any saturation, and re-optimises if any saturation is detected. Navigation System Navigation data is provided in post processing from the RT3003 INS/DGPS within the Navigation-Alignment System. Time synchronisation is achieved by the Hyspex PC emitting regular pulses at a little under 1hz which are recoded as events by the RT3003 module. In this way the two data streams can be aligned very precisely in post processing. Find out more about the Navigation-Alignment System (NAS) Camera Slaving The camera system can optionally be slaved to acquire whenever the Hyspex system is recording. The purpose for this mode is to reduce crew workload during survey operations. Through the CAM menu interface provided on the multi-function display, the camera system can be set to SLAVE mode; in this mode any command to start an acquisition on the Hyspex will also begin an acquisition on the camera; likewise the camera will be stopped when the Hyspex acquisition is ended. The camera can be set to run either on an intervalometer (the usual method) or in continuous mode for very fast shooting. The current camera settings will be used. System Control The Hyspex sensor is controlled by, and its data is logged on, a dedicated rugged PC that we have mounted to a removeable shelf in the rear cabin of the aircraft. This is powered by and connected to the network of the Central Services Module (CSM). Control of the Hyspex system is provided over the network via Remote Desktop Protocol from the Control-Display Computer (CDC). The human interface for this is via the Front Science Panel (FSP) on the right hand side of the cockpit, and includes pushbutton multi-function display capability. All functions required to set up and control the Hyspex system are available through this push-button interface. Platform Compatibility The sensor is embedded within the EF19B sensor package on our ECO-Dimona aircraft. Although it would be compatible with other platforms this would involve significant integration work. Overall the Hyspex system is too large for <25Kg UAS, at least without significant modification to the control and logging systems. Availability We have one Hyspex VNIR1600 sensor. Hyspex VNIR1600 (black) within its mounting block alongside the INS/GNSS unit (red) and the slaved camera. This article was published on 2024-06-25
