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08 Apr 2021
French sensor specialist to develop SWIR linear array for Airbus-led Copernicus contract.
Lynred, the Grenoble company created by the merger of infrared detector makers Sofradir and ULIS, has won a contract to develop a new sensor for satellite imaging.
The short-wave infrared (SWIR) linear array will be integrated into a high-resolution radiometer designed to measure the temperature of the Earth’s land surfaces - and help farmers better manage agricultural land to the level of individual fields.
That radiometer is earmarked for the future Land Surface Temperature Monitoring (LSTM) mission, part of the European Space Agency’s wider Copernicus Earth observation program. LSTM is being coordinated by the Spanish wing of Airbus Defence and Space (ADS).
Predicting droughts
Lynred says that the overall aim of the mission is to improve sustainable agricultural productivity at field-scale in regions experiencing increasing water scarcity and climate variability.
“It has as its objective improving how the agriculture sector predicts droughts and addresses other land degradation issues,” said the French firm.
Philippe Chorier, space business development manager at Lynred, said in a company release: “Lynred is proud to have been selected by ADS to participate in a flagship European environmental program, designed to bring solutions to some of the most serious challenges facing the agricultural sector.”
According to Airbus, the key objective is to deliver global high spatio-temporal measurements of Earth’s surface temperature, day and night.
“Satellite data analysis for mapping, monitoring and forecasting the Earth's natural resources helps to understand what, when and where changes are taking place,” stated the prime contractor after signing a €380 million deal to provide the system last year.
“In particular, this mission will respond to the needs of European farmers to make agricultural production on individual farms more sustainable, as water shortages increase and changes in the environment take place,” explains Airbus.
“Specialists will be able to calculate in real time how much water different plants require in different areas, and how often those plants need to be irrigated.”
Individual field temperatures
On the technical front, Lynred’s SWIR detector will capture infrared light at three different wavelengths (0.945 µm, 1.375 µm and 1.61 µm).
The linear array will feature 1200 pixels in the across-track satellite velocity direction, and 12 pixels in the long-track scanning direction (with scanning methods used to acquire a multispectral image).
Those 12 pixels enable the implementation of a time-delay integration (TDI) scheme for improving signal-to-noise ratio and enhancing image quality directly on the detector chip.
“As a consequence, the interface towards detector electronics is significantly simplified for global detection chain design optimization,” Lynred explains.
Airbus will build the LSTM satellite in Madrid, and, if all goes according to plan, Lynred should deliver the first flight model of the detector by the end of 2023.
Whether or not LSTM makes it into orbit depends on some further funding decisions, but if it is selected launch would be expected towards the end of the current decade. ESA currently lists the mission as a “high-priority candidate”, alongside the “CHIME” hyperspectral imager and others - all of which rely on advanced photonics technologies.
If selected, LSTM will operate from a low-Earth, polar orbit, to map both land-surface temperature and rates of evapo-transpiration with what Airbus says will be unprecedented field-scale detail.
“It will be able to identify the temperatures of individual fields and image the Earth every three days at 50 meter resolution,” claims the company. “This is about 400 times more detail than is currently acquired from space.”
Observations will cover temperatures ranging from approximately -20°C to +30°C, with a precision of 0.3°C.
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