Performance

Sentinel-2 MSI Technical Guide - Performance

Sentinel-2 products respect stringent radiometric and geometric image quality requirements.

Radiometric Performance

The following table shows the spectral band characteristics and the MSI specified performance (radiance sensibility range and SNR).

Band parameter for each spectral band
Band number Spatial Sample Distance (m) Central wavelength (nm) Bandwidth (nm) Radiance sensibility range Lmin < Lref < Lmax
(W.m-2.sr-1.µm-1)
SNR Specification (at Lref)
1 60 443 20 16 < 129 < 588 129
2 10 490 65 11.5 < 128 < 615.5 154
3 10 560 35 6.5 < 128 < 559 168
4 10 665 30 3.5 < 108 < 484 142
5 20 705 15 2.5 < 74.5 < 449.5 117
6 20 740 15 2 < 68 < 413 89
7 20 783 20 1.5 < 67 < 387 105
8 10 842 115 1 < 103 < 308 174
8a 20 865 20 1 < 52.5 < 308 72
9 60 945 20 0.5 < 9 < 233 114
10 60 1 375 30 0.05 < 6 < 45 50
11 20 1 610 90 0.5 < 4 < 70 100
12 20 2 190 180 0.1 < 1.5 < 24.5 100

 

Spectral Response for the Sentinel-2 VNIR Bands

Spectral Response for the Sentinel-2 SWIR Bands

The Level-1 radiometry quality requirements are:

  • Absolute radiometric uncertainty: 3% (goal), 5% (threshold).
  • Inter-band relative radiometric uncertainty: 3%.
  • Multi-temporal relative radiometric uncertainty: 1%.
  • Linearity knowledge accuracy: 1%.
  • Channel-to-channel cross-talk: <0.5%.
  • Modulation Transfer Function (MTF): 0.15 to 0.3 (for 10 m bands) and < 0.45 (for 20 m and 60 m bands).

The objective of absolute radiometric accuracy is 3%. To guarantee this high quality radiometric performance, a full-field and full-pupil on-board diffuser is employed.

The knowledge of the band equivalent wavelength is also very important because an error of 1 nm induces errors of several per cent on the reflectance value, especially in the blue part and in the near-infra-red part of the spectrum.

The equivalent wavelength is known with an uncertainty below 1 nm. In the same way, an error on the absolute calibration measurement affects the physical value accuracy. For this sensor, the inter-band calibration accuracy is 3% and the multi-temporal calibration is 1%. Moreover, the non-linearity of the instrument response has accuracy better than 1% and the channel-to-channel cross-talk is less than 0.5%.

The image quality is due to the system MTF, which is between 0.15 and 0.3 at the Nyquist frequency for spectral bands with 10 m and 20 m spatial resolution and lower than 0.45 for spectral bands with 60 m spatial resolution.

More information on the S2A Spectral Responses can be found here.

Geometric Performance

The Level-1 geometric quality requirements are:

  • A priori absolute geo-location uncertainty (before performing any processing): 2 km 3σ
  • Absolute geolocation uncertainty: 20 m 2σ without GCPs and 12.5 m 2σ with GCPs
  • Multi-temporal registration: 0.3 pixel 2σ including compensation for the effects of terrain height variation with a DEM of SRTM-class accuracy and when image-to-image correlation is applied to data from the same spectral band
  • Multi-spectral registration (for any two spectral bands): 0.3 pixel 3σ

All of these performance requirements for final data products will be verified and validated by processes and algorithms on-board and on-ground corresponding to calibration and validation (cal/val) activities which are the responsibility of the Sentinel-2 Mission Performance Centre (MPC).

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