Concept information
Preferred term
VGT-P
Definition
- The PROBA-Vegetation payload is a multispectral pushbroom spectrometer with 4 spectral bands and with a very large swath of 2285 km to guarantee daily coverage above 35 latitude. The payload consists of 3 identical SI (Spectral Imagers), each with a very compact TMA telescope. Each TMA, having a FOV of 34º, contains 4 spectral bands: 3 bands in the visible range and one band in the SWIR spectral range. The swath TFOV is 103º. 42) 43) 44) 45) VGT-P is restricted to imaging land and dedicated calibration zones. On-board the spacecraft, there is for each spectral imager a land sea mask that is provided by the PI (Principal Investigator). The land sea mask removes the pixels that contain only sea and it dictates when each SI should be in imaging mode. OIP (Optronic Instruments & Products, Belgium) is the industrial prime contractor for the payload and is responsible for the design and development of the PROBA-V instrument and AMOS (Belgium) is responsible for the manufacturing and alignment of the telescope. The major payload challenge lies in the fact that the wide-swath imaging instrument has to fit into a small satellite with limited resources. The TMAs and the SWIR FPA have to be developed for the VGT-P since no COTS products are available. Optical system Type: Pushbroom instrument using a reflective optical design 3 identical TMA telescopes mounted on an optical bench together with the star tracker optical heads allowing precise co-alignment. FOV = 33.6º x 5.5º, a TFOV of nearly 103º is provided with 3 SIs (Spectral Imagers) 4 spectral bands: 3 VNIR centered at (460, 658, 834 nm) and 1 SWIR band (1610 nm) VNIR detector : 3 x 6000 pixels of 13 µm (E2V, France)- quadrilinear AT71547 SWIR detector: liner array composed of 3 mechanically butted detectors of 1024 pixels (Xenics NV, Belgium) Spectral bands VNIR B0: 0.415-0.500 µm (Blue) VNIR B1: 0.580-0.770 µm (Red) VNIR B2 : 0.730-0.960 µm (NIR) SWIR:1.480-1.760 µm Optical parameters Focal length: 109.6 mm Aperture diameter: 18.6 mm f/number: 6 Size: 90 mm x 110 mm x 140 mm (length x width x height) Geometrical performance - Swath width - GSD (Ground Sample Distance) 2285 km (103º of 3 TMAs) at 820 km altitude 300 m (baseline) - VNIR : 100 m at nadir, 360 m at edge of swath - SWIR : 200 m at nadir, 600 m at edge of swath Spectral parameters VNIR bands: 447-493 nm (blue); 610-690 nm (red); 777-893 nm (NIR) SWIR band: 1570-1650 nm Mechanical concept - 3 telescopes are mounted on highly rigid and light-weighted optical bench - Star tracker mounted on the same bench to minimize the pointing knowledge error - Optical bench thermally decoupled from satellite - Radiator for heat removal from the optical bench - Heater and thermostats close to FPAs Electrical concept - ROE (Read-out Electronics) of the FPAs partly on optical bench, partly on satellite panel - DHU (Data Handling Unit) dealing with image data, housekeeping and commands - PSU (Power Supply Unit) - Instrument power consumption = 43.2 W Instrument mass, size 35 kg, 200 mm x 812 mm xs 350 mm Instrument power consumption 30 W (peak) Data compression CCSDS 133.0 B-1 Data rate 7.15 Mbit/s (after compression) DHU Interfaces with ADPMS 2 Packetwire interfaces 1 UART interface to control and monitor VGT-P 3 Discrete pulses (5V CMOS TTL) to synchronize VGT-P on-board timing and switch on/off survival heater circuit and PSU 6 AD590 temperature sensors Power: 28 V (en)
Broader concept
Change note
- 2018-07-10 07:15:57.0 [mmorahan] Insert Concept add broader relation (VGT-P [88094b8c-c68c-4e4f-a4d9-1d5b6e15ba5b,367803] - Imaging Spectrometers/Radiometers [944b7691-af37-4fb4-9393-c114e7997829,347979]);
- 2018-07-10 07:21:02.0 [mmorahan] insert AltLabel (id: null category: primary text: Vegetation Instrument - PROBA language code: en); insert Definition (id: null text: The PROBA-Vegetation payload is a multispectral pushbroom spectrometer with 4 spectral bands and with a very large swath of 2285 km to guarantee daily coverage above 35 latitude. The payload consists of 3 identical SI (Spectral Imagers), each with a very compact TMA telescope. Each TMA, having a FOV of 34º, contains 4 spectral bands: 3 bands in the visible range and one band in the SWIR spectral range. The swath TFOV is 103º. 42) 43) 44) 45) VGT-P is restricted to imaging land and dedicated calibration zones. On-board the spacecraft, there is for each spectral imager a land sea mask that is provided by the PI (Principal Investigator). The land sea mask removes the pixels that contain only sea and it dictates when each SI should be in imaging mode. OIP (Optronic Instruments & Products, Belgium) is the industrial prime contractor for the payload and is responsible for the design and development of the PROBA-V instrument and AMOS (Belgium) is responsible for the manufacturing and alignment of the telescope. The major payload challenge lies in the fact that the wide-swath imaging instrument has to fit into a small satellite with limited resources. The TMAs and the SWIR FPA have to be developed for the VGT-P since no COTS products are available. Optical system Type: Pushbroom instrument using a reflective optical design 3 identical TMA telescopes mounted on an optical bench together with the star tracker optical heads allowing precise co-alignment. FOV = 33.6º x 5.5º, a TFOV of nearly 103º is provided with 3 SIs (Spectral Imagers) 4 spectral bands: 3 VNIR centered at (460, 658, 834 nm) and 1 SWIR band (1610 nm) VNIR detector : 3 x 6000 pixels of 13 µm (E2V, France)- quadrilinear AT71547 SWIR detector: liner array composed of 3 mechanically butted detectors of 1024 pixels (Xenics NV, Belgium) Spectral bands VNIR B0: 0.415-0.500 µm (Blue) VNIR B1: 0.580-0.770 µm (Red) VNIR B2 : 0.730-0.960 µm (NIR) SWIR:1.480-1.760 µm Optical parameters Focal length: 109.6 mm Aperture diameter: 18.6 mm f/number: 6 Size: 90 mm x 110 mm x 140 mm (length x width x height) Geometrical performance - Swath width - GSD (Ground Sample Distance) 2285 km (103º of 3 TMAs) at 820 km altitude 300 m (baseline) - VNIR : 100 m at nadir, 360 m at edge of swath - SWIR : 200 m at nadir, 600 m at edge of swath Spectral parameters VNIR bands: 447-493 nm (blue); 610-690 nm (red); 777-893 nm (NIR) SWIR band: 1570-1650 nm Mechanical concept - 3 telescopes are mounted on highly rigid and light-weighted optical bench - Star tracker mounted on the same bench to minimize the pointing knowledge error - Optical bench thermally decoupled from satellite - Radiator for heat removal from the optical bench - Heater and thermostats close to FPAs Electrical concept - ROE (Read-out Electronics) of the FPAs partly on optical bench, partly on satellite panel - DHU (Data Handling Unit) dealing with image data, housekeeping and commands - PSU (Power Supply Unit) - Instrument power consumption = 43.2 W Instrument mass, size 35 kg, 200 mm x 812 mm xs 350 mm Instrument power consumption 30 W (peak) Data compression CCSDS 133.0 B-1 Data rate 7.15 Mbit/s (after compression) DHU Interfaces with ADPMS 2 Packetwire interfaces 1 UART interface to control and monitor VGT-P 3 Discrete pulses (5V CMOS TTL) to synchronize VGT-P on-board timing and switch on/off survival heater circuit and PSU 6 AD590 temperature sensors Power: 28 V language code: en);
- 2018-07-10 07:22:22.0 [mmorahan] insert WeightedRelation (id: null related concept uuid: 6f507389-2c7c-41b4-a638-95bdc73b63a3 relationship type: null relationship value: null generated by: null);
URI
https://gcmd.earthdata.nasa.gov/kms/concept/88094b8c-c68c-4e4f-a4d9-1d5b6e15ba5b
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