HYPSTAR® is an autonomous hyperspectral radiometer system designed for surface reflectance validation of optical satellite data products. HYPSTAR captures radiance and irradiance measurements.
A HYPSTAR system consists of a hyperspectral VNIR spectrometer, an optional SWIR spectrometer, and a simple RGB imaging camera alongside the hyperspectral measurements. It also includes an LED source for calibration monitoring, a pan-tilt mechanism, auxiliary sensors (pressure, humidity, temperature, rain, light, two external cameras), and a standardised data stream for easy and systematic exploitation by downstream validation networks WATERHYPERNET and LANDHYPERNET.
Once deployed in the field, a HYPSTAR system integrates into the WATERHYPERNET or LANDHYPERNET network dedicated to satellite validation, or it may operate independently. The networks automatically acquire measurements from the sites in near real-time, do magic, and provide results with associated uncertainties evaluated according to ISO/GUM. The uncertainty estimation closely follows the work of the FRM4SOC, FRM4SOC-2, and FRM4VEG projects.
The system is available in two versions: HYPSTAR-SR for water sites and HYPSTAR-XR for land sites. Both have been thoroughly tested in diverse and challenging conditions, including various applications (water, land), environments (cold/hot, wet/dry, calm/windy, biofouling, etc.), and logistics (accessible/remote, standalone/heavily instrumented sites, well-protected/vulnerable to humans, etc.) during the H2020/HYPERNETS project.
Ten HYPSTAR-SR and eleven HYPSTAR-XR prototypes have been deployed for various periods, ranging from a few days to several years. These deployments have taken place at locations including the Acqua Alta Oceanographic Tower in Italy, the Río de la Plata in Argentina, the Gobabeb Desert in Namibia, and the Princess Elisabeth Antarctica Research Station, among others.
HYPSTAR technical specifications
| Model | HYPSTAR-SR | HYPSTAR-XR |
|---|---|---|
| Weight of top-of-the-mast assembly | 6.3 kg | 7.8 kg |
| Power supply (entire system) | 12 VDC, 40 W | 12 VDC, 50 W |
| Operating temperature | −25°C to 45°C | |
| Storage temperature | −35°C to 70°C | |
| Spectroradiometer | ||
| Measured quantity | radiance and irradiance (multiplexed) | |
| Field of view | 2° (radiance), 180° (irradiance) | 5° (radiance), 180° (irradiance) |
| Detector array | 2048 px Si | 2048 px Si, 256 px InGaAs |
| Spectral range | 380–1020 nm | 380–1680 nm |
| Spectral sampling interval | 0.5 nm | 0.5 nm (VNIR), 3 nm (SWIR) |
| Spectral resolution | 3 nm | 3 nm (VNIR), 10 nm (SWIR) |
| ADC resolution | 16 bit | |
| Integration time | 1–65000 ms, independent for VNIR and SWIR | |
| Shutter | internal | |
| Target camera | 5 MP, RGB, 57° vertical and 44° horizontal FOV | |
| Communication interface | RS-485, half duplex, 115.2–8000 kbit s−1 | |
| Housing material | anodised marine grade aluminium | |
| Environmental protection | IP 67 | |
| Dimensions (DxL) | Ø110 mm × 267 mm | Ø110 mm × 434 mm |
| Weight | 1.5 kg | 3 kg |
| Power supply | 8–30 VDC, 6 W | 8–30 VDC, 25 W |
| Reference unit | ||
| Light source | Ø42 mm diffuse, white LED spectrum | |
| Communication interface | RS-485, half duplex, 115.2 kbit s−1 | |
| Housing material | anodised marine grade aluminium | |
| Environmental protection | IP 67 | |
| Dimensions (DxL) | Ø110 mm × 108 mm | |
| Weight | 0.8 kg | |
| Power supply | 8–30 VDC, 10 W | |
| Pointing unit | ||
| Communication interface | RS-485, half duplex, 2.4 kbit s−1, PELCO D protocol | |
| Range | 360° pan and tilt | |
| Speed | 24° s‒1 pan, 6° s‒1 tilt | |
| Repeatability | < 1° | |
| Backlash | < 0.15° | |
| Housing material | painted die cast aluminium | |
| Environmental protection | IP 68 | |
| Weight | 1.9 kg | |
| Host unit | ||
| Operating system | Linux | |
| Communication interface | Ethernet, WiFi, mobile | |
| Data storage | 64 GB solid state drive | |
| Enclosure material | polycarbonate | |
| Environmental protection | IP 66 | |
| Dimensions (HxWxD) | 500 mm × 400 mm × 210 mm | |
| Weight | 10 kg + cables 4 kg | |
The development of HYPSTAR® was funded by the European Union’s Horizon 2020 Research and Innovation Program under Grant Agreement No. 775983 (“HYPERNETS project“).
