OCR calibration and characterization review Sample Clauses

OCR calibration and characterization review. As regards requirements on radiometer performance, the NASA Ocean Optics Protocols Volume II, in Chapter 3 [22], already back in 2003 provided insight and recommendations on how instrument calibration and characterisation should be performed as well as, in Chapter 2, some minimum specifications or requirements for individual characteristics, e.g. (their Table 2.2) “straylight rejection of 10-6”, “signal:noise ratio of 1000:1 (at minimum)”, etc. The 2019 IOCCG Ocean Optics Protocols adopted a similar approach, including recommended specifications (e.g. Table 3-1 reproduced from their Table 2.2), which can be considered as target values,as well as a combination of limits beyond which characterisation and correction are required, e.g. “Sensors with temperature coefficients greater than 0.01% per °C should be characterized and a correction applied to the data to constrain residual temperature dependence below 0.01% per °C”. It is noted that some of the specifications provided in Table 3-1 may be difficult to achieve with current hyperspectral radiometers. E.g. correction of non-linearities to 0.1% may be very challenging. Straylight rejection of 10-5 (at the maximum signal level) may be difficult to achieve [28] and translation of the driving requirement of “residual after correction for this effect, below 1% in each band across the full spectral range” into requirements on the radiometer depends on the spectral composition of the (undefined) target. It is the ambition of the FRM4SOC- 2 project to better understand how the final measurement uncertainty for water reflectance is affected by uncertainties from each such radiometer instrument characteristic, to assist in refining requirements on instrument characterisation.