PERFORMANCES REQUIREMENTS

Radiometric performance is expressed in term of signal to noise ratio for a reflectance of 0.1 assuming the sun is at the zenith.

Geometrical
With a field of view of ± 43° along track and ± 51° cross track, POLDER as a 2400 km swath which allows a daily coverage of almost the whole Earth.

The instrument resolution is 6 km x 7 km at nadir, increasing at higher incidence angles due to the Earth's curvature. A pixel size of 6 km x 6 km is obtained after resampling on the geocoded POLDER grid.



REGISTRATION PERFORMANCE

0.1 of a pixel for the 3 polarized components in the same spectral band.

0.1 of a pixel for different spectral bands in the same sequence.

0.2 of a pixels for multidirectional registration.

0.4 pixels for multitemporal registration.

1 pixel for absolute registration.


Radiometrical
In order to optimize the radiometric quality of measurements, two exposure times may be programmed: the short exposure time for high-reflectance targets (High Dynamic Mode) and the long one for low-reflectance targets (Low Dynamic Mode).



	Mode	443P	443NP	490	565	670P	763	765	865P	910
Bandwidth (nm)		20	20	20	20	20	10	40	40	20
Reflectance range	hight dynamic	0.05 - 1.1	NA	NA	NA	0.1 - 1.1	0.07 - 1.1	0.07 - 1.1	0.07 - 1.1	0.1 - 1.1
	low dynamic	NA	0.05 - 0.22	0.034 - 0.17	0.019 - 0.11	0.013 - 0.25	0.008 - 0.25	0.008 - 0.25	0.008 - 0.25	0.007 - 0.25
Signal to noise ration	high dynamic	189	NA	NA	NA	196	149	196	196	188
	low dynamic	NA	400	500	714	500	385	476	476	357


Calibration performances

2 to 3 % for absolute calibration (Rayleigh scattering).
1 % for interband calibration (in glitter conditions).
1 % for low frequency interpixel calibration (over deserts and in glitter conditions).
0.1% for high frequency interpixel calibration (over spatially homogeneous cloud cover).

The polarization ratio is calibrated over targets, applying both high and low polarization, with an expected accuracy of 1 %.