Quarterly Image Quality Reportproba-v.vgt.vito.be/.../probav_d9_qir-007_2015-q3_v1.0.pdfQuarterly...

QUARTERLY IMAGE

QUALITY REPORT

IQR#007

Reporting period from 16/06/2015 to 15/09/2015

Reference: PROBA-V_D9_QIR-007_2015-Q3_v1.0 Author(s): Sindy Sterckx, Stefan Adriaensen, Iskander Benhadj Version: 1.0 Date: 21/06/2015

Quarterly Image Quality Report PROBA-V Operations Contract No. 4000111291/14/I-LG - 1310174

PROBA-V_D9_QIR-007_2015-Q3_v1.0 Quarterly Image Quality Report of 59

DOCUMENT CONTROL

Signatures Author(s) Sindy Sterckx, Stefan Adriaensen, Iskander Benhadj Reviewer(s) Dennis Clarijs Approver(s) Dennis Clarijs Issuing authority VITO N.V.

Change record

Release Date Pages Description Editor(s)/Reviewer(s)

1.0 21/09/2015 All Initial version



TABLE OF CONTENT

1. RADIOMETRIC IMAGE QUALITY ................................................................................ 5 1.1. Summary .............................................................................................................................................. 5 1.2. Assessment of the radiometric accuracy .............................................................................................. 6

1.2.1. Absolute radiometric accuracy....................................................................................................... 6 1.2.1.1. Libya-4 desert calibration .......................................................................................................... 6 1.2.1.2. Rayleigh calibration.................................................................................................................. 16

1.2.2. Inter-band radiometric accuracy .................................................................................................. 20 1.2.2.1. Calibration over deep convective clouds (DCC) ....................................................................... 20

1.2.3. Multi-temporal radiometric accuracy .......................................................................................... 22 1.2.3.1. Desert calibration over multiple sites ...................................................................................... 22 1.2.3.2. Lunar calibration ...................................................................................................................... 22

1.3. Dark current ........................................................................................................................................ 25 1.3.1. Methodology ................................................................................................................................ 25 1.3.2. VNIR results .................................................................................................................................. 25 1.3.3. SWIR results ................................................................................................................................. 29

1.4. High Frequency Equalisation/Striping ................................................................................................. 34 1.5. Experimental vignetting/strip non-uniformity analysis ....................................................................... 41 1.6. Radiometric ICP file ............................................................................................................................. 45

2. GEOMETRIC IMAGE QUALITY ................................................................................. 48 2.1. Summary ............................................................................................................................................. 48 2.2. Assessment of the geometric accuracy on L1C data ............................................................................ 49 2.3. Assessment of the geometric accuracy on L2 data .............................................................................. 50

2.3.1. Absolute geometric accuracy ....................................................................................................... 50 2.3.2. Inter-band geometric accuracy .................................................................................................... 57 2.3.3. Multi-temporal geometric accuracy ............................................................................................. 58

2.4. Geometric ICP file................................................................................................................................ 59



1. Radiometric Image Quality

1.1. Summary For all SWIR strips (except for Right SWIR 3, which was updated with 2.8 % in February 2015) a decreasing trend in the observed radiances is visible in the Libya-4 results. In order to reduce uncertainties in proposed updates for the absolute calibration coefficients for the different SWIR strips, a trend analysis was also performed on OSCAR desert calibration results obtained over seven different desert sites i.e. Libya1, Libya2, Libya3, Libya4, Niger1, Niger2 and Niger3. The median % decrease over all these desert sites was used to determine the % percentage update for the absolute calibration parameters. These are listed in Table 1.

Strip A

left swir1 -1.7

left swir2 -1.9

leftswir3 -0.9

center swir1 -1.4

center swir2 -1.3

center swir3 -1.3

right swir1 -1.8

right swir2 -3.3

right swir3 NA

Table 1. Absolute calibration coefficients updates SWIR strips

In order to prevent stepwise updates in the future it will be analyzed in the coming months if a degradation model can be set-up for the different strips based on all the results obtained. Vignetting analysis on the different SWIR strips have been set-up over a set of desert sites. Preliminary results indicate some slight strip non-unformity at the edge of the Center SWIR3, Left SWIR3, Left SWIR2, Left SWIR1 and Right SWIR 1 strip and at the center of Right SWIR1 and Center SWIR3. The exact quantification of the non-uniformities and the retrieval of equalization coefficients to correct for it, requires some further analysis in order to properly discriminate between instrument induced non-unformities and BRDF or site related effects. A slight decrease is seen for August-September 2015 in the RED and NIR Libya-4 results for all cameras. A slight decrease is also observed in the DCC NIR interband results. This trend will closely be monitored in the coming weeks in order to evaluate the need for an absolute calibration parameter update. Sudden jumps in the dark current values of a few SWIR pixels , distributed over the different strips and cameras, have been observed which explains the sudden occurence of a few minor stripes in the SWIR images. An update of the SWIR dark current values has therefore regularly performed.



1.2. Assessment of the radiometric accuracy

1.2.1. Absolute radiometric accuracy

The absolute radiometric calibration requirement for PROBA-V specifies a 5 % absolute accuracy. This requirement is assessed through vicarious calibration over Libya-4 desert site and Rayleigh calibration zones.

1.2.1.1. Libya-4 desert calibration

Methodology

The nominal approach for assessing the absolute radiometric accuracy relies on the comparison between cloud-free TOA reflectance as measured over the Libya-4 desert site by PROBA-V and the modelled TOA reflectance values, following the approach described in [LIT1]. Validation of the approach using various satellite data (i.e. AQUA-MODIS, MERIS, AATSR, PARASOL, SPOT-VGT) has shown that absolute calibration over the Libya-4 desert is achievable with this approach with an accuracy of 3% [LIT1, LIT2].

Results

In Figure 1, Figure 4 and Figure 7 the monthly averaged results (𝑎𝑣𝑔(𝜌𝑇𝑂𝐴𝑘,𝑃𝑟𝑜𝑏𝑎𝑉(𝐴𝑐𝑜𝑚)

𝜌𝑇𝑂𝐴𝑘,𝑚𝑜𝑑𝑒𝑙⁄ ) )

and its standard deviation are given for respectively LEFT, CENTER and RIGHT camera. The individual area-averaged results are given in Figure 2, Figure 5, Figure 8 and Figure 3, Figure 6, Figure 9 with a 3 % error bar (as expected uncertainty for an individual result) for respectively VNIR and SWIR strips. Results are obtained with the absolute calibration parameters valid for the day of acquisition i.e. no reprocessing is done on the results. Images acquired after an update are processed with the updated calibration coefficient. A slight decrease is seen for August-September 2015 in the RED and NIR Libya-4 results for all cameras. This trend will closely be monitored in the coming weeks in order to evaluate the need for an absolute calibration parameter update. The decreasing trend, since start of the operational phase, remains visible in the Libya-4 results for all SWIR strips (except for RIGHT SWIR 3 strip, for which the absolute calibration coefficients have been updated with 2.8 % previously). An update of the SWIR absolute calibration coefficients is therefore deemed to be necessary to correct for the degradation. We refer to section 1.3 in which we discuss this in further detail.



Figure 1. Libya-4 desert calibration results: LEFT monthly averaged results

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Figure 2. Libya-4 desert calibration results: LEFT VNIR- individual results



Figure 3. Libya-4 desert calibration results: LEFT SWIR – individual results



Figure 4. Libya-4 desert calibration results: CENTER monthly averaged results

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Figure 5. Libya-4 desert calibration results: CENTER VNIR-individual results



Figure 6. Libya-4 desert calibration results: CENTER SWIR-individual results



Figure 7. Libya-4 desert calibration results: RIGHT monthly averaged results

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Figure 8. Libya-4 desert calibration results: RIGHT VNIR-individual results



Figure 9. Libya-4 desert calibration results: RIGHT SWIR- individual results



1.2.1.2. Rayleigh calibration

Methodology

The Rayleigh calibration approach is an absolute calibration method for BLUE and RED bands. The primary assumption of the approach is that the ocean does not contribute to the Top-Of-Atmosphere (TOA) signal in the NIR. The contribution of aerosol scattering is derived from the NIR reference band where molecular scattering is negligible. The aerosol content estimated from the NIR band is then transferred to the BLUE and RED band to model the TOA radiance with a radiative transfer code. The simulated radiance values are then compared with the measured values.

Results

The scene averaged Rayleigh results ((𝜌𝑇𝑂𝐴𝑘,𝑃𝑟𝑜𝑏𝑎𝑉(𝐴𝑐𝑜𝑚)

𝜌𝑇𝑂𝐴𝑘,𝑚𝑜𝑑𝑒𝑙⁄ ) ) (with a 4 % error bar as rough

indication of uncertainty of one individual result) obtained since January 2014 for LEFT, CENTER and RIGHT camera are given in respectively Figure 10, Figure 11 and Figure 12. Results are obtained with the absolute calibration parameters valid for the day of acquisition i.e. no reprocessing is done on the results. Images acquired after an update are processed with the updated calibration coefficient. All Rayleigh calibration results remain well within the 5 % absolute accuracy requirement.



Figure 10. Rayleigh absolute calibration results: LEFT camera



Figure 11. Rayleigh absolute calibration results: CENTER camera

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Figure 12. Rayleigh absolute calibration results: RIGHT camera

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1.2.2. Inter-band radiometric accuracy

The inter-band radiometric calibration requirement for PROBA-V specifies a 3 % inter-band accuracy. This requirement is assessed through vicarious calibration over deep convective clouds.

1.2.2.1. Calibration over deep convective clouds (DCC)

Methodology

The DCC approach is an inter-band calibration method. It makes use of bright, thick, high altitude, convective clouds over oceanic sites. Their reflective properties are spectrally flat in visible and near-infrared and the only contributions to the observed signal are from the cloud reflectance, molecular scattering and ozone absorption which can be modelled with a radiative transfer code. The cloud reflectance in the non-absorbing VNIR bands is mainly sensitive to the cloud optical thickness. The DCC method uses the TOA reflectance in the ‘reference’ RED band to estimate cloud optical thickness assuming a fixed ice particle model. The derived cloud optical thickness is then used to model using a radiative transfer code the TOA reflectance for the BLUE and NIR band. The method is not suited for the SWIR band as clouds are no longer spectrally uniform in this spectral region.

Results

The DCC inter-band calibration is defined by reference to the used RED reference band. The average DCC inter-band calibration result per month (from March 2015 to August 2015) is given in Figure 13 for all cameras. Results are obtained with the absolute calibration parameters valid for the day of acquisition i.e. no reprocessing is done on the results. Images acquired after an update are processed with the updated calibration coefficient. DCC interband calibration results remain stable for the BLUE strip of the different camera’s. However a slight decreasing trend is observed in the NIR strip interband calibration results of the three cameras. As mentioned under 1.2.1.1 we will closely monitor the trends observed in the NIR strips in order to investigate the necessity of an update of the absolute calibration coefficients.



Figure 13. DCC inter-band calibration results: LEFT, CENTER and RIGHT camera



1.2.3. Multi-temporal radiometric accuracy

1.2.3.1. Desert calibration over multiple sites

The OSCAR desert calibration approach is applied to PROBA-V data over a series of homogeneous desert sites. The BRDF RPV parameters derived by Govaerts and Clerici (2004) are used to model the surface BRDF. It should be noted that for Libya-4 (and for Niger-2) updated RPV parameters were derived in Govaerts et al. (2013) to improve the absolute accuracy of the method; for the other desert sites this was not done. Therefore, vicarious calibration results obtained for these sites are only used relatively (i.e. multi-temporally) and not absolutely. The aim is to verify if similar degrading trends are observed in the SWIR strips over the different desert sites. In Table 2 the trend is given since approximately November 2013. Please note that values for Libya-4 might slightly differ from those given previously. This is because section 1.2.1.1 contains results up to mid-September 2015 while the analyses for Table 2 were already done mid-August. It is clear from the table that the largest trend is observed for Right Swir2 strip. The trend is consistent over all desert sites. Also for the other strips (except SWIR3 Right, which has previously updated) a decreasing trend is observed for almost all the sites. However there is a larger variation in these values. As can be seen in the table largest trends are observed mostly over the Libya-4 site. In order not to overestimate the degradation, it is decided to use the median observed trend per strip over the selected desert sites for defining the change to be made to the absolute calibration parameters. A first update (of 1 %) to Right SWIR2 strip was done on August 26, 2015. A second update (of 2.3%) to this strip will be performed now, for the other strips (except Right Swir3) an update will also be done based on the median observed linear trend listed in Table 2.

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libya1 -1.7 -1.8 -1.3 -1.4 -1.5 -1.6 -0.7 -3.1 0.2

libya2 -1.0 -2.0 -0.4 -1.1 -0.9 -0.3 -1.3 -3.3 0.0

libya3 -1.3 -1.4 0.0 -0.7 -1.3 -1.1 -1.0 -3.2 0.8

libya4 -2.8 -3.0 -2.7 -1.9 -2.5 -2.7 -1.9 -4.1 -0.4

niger1 -2.2 -0.8 -2.7 -1.8 -1.6 -2.5 -3.3 1.9

niger2 -2.2 -2.2 -1.0 -1.5 -0.9 -0.8 -1.8 -3.3 -0.3

niger3 -0.9 -1.1 -0.9 -0.6 -1.0 -1.3 -2.6 -3.1 0.9

median -1.7 -1.9 -0.9 -1.4 -1.3 -1.3 -1.8 -3.3 0.2

Table 2. Linear trend since November 2013 over different desert sites

1.2.3.2. Lunar calibration

The Lunar calibration results for the VNIR and SWIR2 CENTER camera bands, normalised to June 2013, are given in Figure 14. The results showed in this figure are obtained with the absolute calibration parameters valid for the day of acquisition i.e. no reprocessing is done on the results. Images acquired after an update are processed with the updated calibration coefficient. On the



other hand we have given in Figure 15 the results for a constant calibration coefficient in order to monitor the stability of the instrument. No clear trend is observed in the lunar calibration results for the VNIR and SWIR2 CENTER strips since the start of the operational phase. It is, at the moment, still unclear why the slight decreasing trend observed in the desert Center SWIR2 strip (of about 1.3 %) since November 2013 is not confirmed by the lunar calibration results . On the other hand, we do see a decreasing trend during the commissioning phase in both the Libya-4 and Lunar calibration Center swir2 results.

Figure 14. Lunar Calibration results CENTER camera normalised to June taking into account calibration coefficient updates during operational phase.

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Figure 15. Lunar Calibration results CENTER camera normalised to June considering constant Absolute calibration coefficients.

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1.3. Dark current

1.3.1. Methodology

Monthly difference plots : o All dark current results obtained during a period of one month for observations

performed with a long integration time are averaged per pixel. This gives for each pixel the monthly averaged dark current, expressed in LSB/s, and its standard deviation.

o The dark current results and its standard deviation expressed in LSB/s are converted to LSB using a maximum Integration Time for nominal acquisitions. For VNIR strips 0.006s is used. For SWIR strips 0.02s.

o The differences between months (i.e. Month3-Month2, Month2-Month1) are calculated. This is done for both the dark current and the stdev. Differences are visualized in plots in blue the dark current difference in LSB is plotted, in red the standard deviation difference. This latter is an indicator of changes in the dark current noise between months.

As mentioned in the previous quarterly report (IQR#005) the integration time used for the SWIR dark current acquisitions has been decreased from 3s to 0.2 s since 2015.

1.3.2. VNIR results

Monthly difference plots for VNIR dark currents are given in Figure 16, Figure 17 and Figure 18 for respectively LEFT, CENTER and RIGHT camera. Dark current differences for the VNIR bands are well below 1 DN , except for pixel 4676 of the Left BLUE strip, for which a jump in DC of about 1 DN (at nominal integration time) is observed in July.



Figure 16. LEFT camera VNIR: Monthly difference (MAY to AUG 2015) in dark current (Blue) and standard deviation (Red) of the monthly averaged results.

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Figure 17. CENTER camera VNIR: Monthly difference (MAY to AUG 2015) in dark current (Blue) and standard deviation (Red) of the monthly averaged results.

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Figure 18. RIGHT camera VNIR: Monthly difference (MAY to AUG 2015) in dark current (Blue) and standard deviation (Red) of the monthly averaged results.

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1.3.3. SWIR results

Monthly difference plots for SWIR dark currents are given in Figure 19,Figure 20 and Figure 21 for respectively LEFT, CENTER and RIGHT camera. A dark current outlier analysis is performed for pixels having for at least one month a dark current expressed in LSB larger than the DC THRESHOLD. This DC THRESHOLD is set to 4 LSB. For those pixels the following dark current pixel status are given :

Both monthly differences > 4 LSB ? Quality is “H DC BAD” One monthly difference > 4 LSB ? Quality is “H DC NOK”. Both monthly differences < 4 LSB ? Quality is “H DC OK”

In Table 3 , Table 4 and Table 5 the resulting SWIR dark current status during the last 3 months is reported for respectively LEFT, CENTER and RIGHT camera. Similarly as in previous reporting periods jumps in the dark current values of a few SWIR pixels is observed, requiring regular updates of ICP dark current values.



Figure 19. LEFT camera SWIR: Monthly difference (MAY to AUG 2015) in dark current (Blue) and standard deviation (Red) of the monthly averaged results.

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Figure 20. CENTER camera SWIR: Monthly difference (MAY to AUG 2015) in dark current (Blue) and standard deviation (Red) of the monthly averaged results.

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Figure 21. RIGHT camera SWIR: Monthly difference (MAY to AUG 2015) in dark current (Blue) and standard deviation (Red) of the monthly averaged results.

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Table 3. LEFT SWIR dark current pixel outliers (ID L1A).

Table 4. CENTER SWIR dark current pixel outliers (ID L1A)

Table 5. RIGHT SWIR dark current pixel outliers (ID L1A)

471 H DC BAD 284 H DC NOK 115 H DC BAD 443 H DC NOK 294 H DC BAD 115 H DC BAD 120 H DC NOK 35 H DC NOK 115 H DC NOK

28 H DC NOK 294 H DC NOK 85 H DC NOK 471 H DC NOK 77 H DC NOK 85 H DC NOK 751 H DC NOK 77 H DC NOK 177 H DC NOK

443 H DC NOK 752 H DC NOK 216 H DC NOK 751 H DC NOK 982 H DC NOK 501 H DC NOK 69 pixels H DC OK 294 H DC NOK 500 H DC NOK

519 H DC NOK 982 H DC NOK 225 H DC NOK 65 pixels H DC OK 98 pixels H DC OK 768 H DC NOK 102 pixels H DC OK 501 H DC NOK

956 H DC NOK 92 pixels H DC OK 406 H DC NOK 819 H DC NOK 716 H DC NOK

57 pixels H DC OK 675 H DC NOK 252 pixels H DC OK 819 H DC NOK

768 H DC NOK 824 H DC NOK



906 H DC NOK 267 pixels H DC OK

240 pixels H DC OK

LEFT

Apr-May-Jun

SWIR1 SWIR2 SWIR3

Jun-Jul-Aug

SWIR1 SWIR2 SWIR3

May-Jun-Jul

SWIR1 SWIR2 SWIR3

51 H DC NOK 634 H DC BAD 868 H DC BAD 369 H DC NOK 753 H DC BAD 468 H DC NOK 545 H DC BAD 369 H DC NOK 308 H DC NOK

1021 H DC NOK 53 H DC NOK 30 H DC NOK 545 H DC NOK 53 H DC NOK 868 H DC NOK 547 H DC BAD 520 H DC NOK 723 H DC NOK

76 pixels H DC OK 753 H DC NOK 468 H DC NOK 547 H DC NOK 369 H DC NOK 938 H DC NOK 848 H DC BAD 753 H DC NOK 152 H DC NOK

82 pixels H DC OK 890 H DC NOK 624 H DC NOK 520 H DC NOK 979 H DC NOK 369 H DC NOK 88 pixels H DC OK 938 H DC NOK

60 pixels H DC OK 83 pixels H DC OK 634 H DC NOK 61 pixels H DC OK 624 H DC NOK 979 H DC NOK

82 pixels H DC OK 84 pixels H DC OK 62pixels H DC OK

CENTER

MAY-JUNE-JULY

SWIR1 SWIR2 SWIR3

JUNE-JULY-AUG

SWIR1 SWIR2 SWIR3

APR-MAY-JUN

SWIR1 SWIR2 SWIR3

162 H DC NOK 438 H DC BAD 777 H DC NOK 212 H DC BAD 438 H DC BAD 160 H DC NOK 212 H DC NOK 438 H DC BAD 160 H DC NOK

182 H DC NOK 754 H DC NOK 799 H DC NOK 162 H DC NOK 909 H DC BAD 218 H DC NOK 960 H DC NOK 102 H DC NOK 183 H DC NOK

212 H DC NOK 957 H DC NOK 907 H DC NOK 960 H DC NOK 670 H DC NOK 506 H DC NOK 114 pixels H DC OK 909 H DC NOK 218 H DC NOK

422 H DC NOK 548 H DC NOK 73 pixels H DC OK 107 pixels H DC OK 957 H DC NOK 840 H DC NOK 99 pixels H DC OK 506 H DC NOK

774 H DC NOK 670 H DC NOK 92 pixels H DC OK 907 H DC NOK 558 H DC NOK

928 H DC NOK 909 H DC NOK 78 pixels H DC OK 810 H DC NOK

96 pixels H DC OK 92 H DC NOK 828 H DC NOK

81 pixels H DC OK 86 pixels H DC OK

APR-MAY-JUN

RIGHT

MAY-JUN-JULMAY-JUN-JUL



1.4. High Frequency Equalisation/Striping Methodology

The high frequency interpixel variation or equalization differences are estimated on radiometrically corrected images i.e. the radiometric model is applied including the equalization coefficients (𝑔𝑖). If they are correct, they remove all the pixel to pixel non-uniformity. In principle the multi-angular method then detects no non-uniformities, only noise if systematic non-uniformities are detected, they can be viewed as corrections to the existing equalization coefficients (∆𝑔𝑖, ℎ𝑖𝑔ℎ). Working like this is in fact an advantage as it focuses entirely on the changes from the existing coefficients. The coefficients can be updated by multiplying the new estimates (“correction coefficients”) with the old ones:

𝑔𝑖, 𝑛𝑒𝑤 = 𝑔𝑖 𝑥∆𝑔𝑖, ℎ𝑖𝑔ℎ The ∆𝑔𝑖, ℎ𝑖𝑔ℎ are estimated as follows:

An input image is taken, containing as little variation in the scene as possible. Image containing uniform snow areas over Antarctica or Greenland during local summer are ideal for VNIR bands. For SWIR bands images over homogeneous desert sites (e.g. Libya4) are used.

Low pass image: is obtained by calculating an averaging filter in the along track direction.

HFRR (high frequency relative response) image is the ratio between the original and the low pass image. It contains only the high frequency information.

In the HFRR image, the trimmed mean is calculated in the along track direction (using all pixel values of a column).

The average and standard deviation over the considered time period is calculated.

Results

Some multi-angular calibration acquisitions have been performed for the VNIR strips over the Greenland calibration zone in August 2015. Due to the only partial coverage of most of the strips with snow/ice fields the multi-calibration results were subject to some artefacts related to the water areas covering parts of the strips. Results are therefore not shown here. High Frequency/striping analyses for the SWIR strips over desert sites has been performed twice during the reporting period i.e. mid of August (Figure 22, Figure 23 and Figure 24) and mid of September (Figure 25, Figure 26 and Figure 27). Please note that no equalisation updates have been done during the reporting period. When comparing these figures with dark current difference profiles, it can be seen that several of the stripes are related to dark current jumps. For example, the stripes observed for Center Swir1 strip in August at pixel 545 and pixel 547 are directly linked to DC jump in August for these pixels. In the equalisation profiles of September these pixels do not show up anymore, probably due to the DC update end of August. There are no SWIR pixels showing ∆𝑔𝑖, ℎ𝑖𝑔ℎ values larger than 1.03 in the September analysis.



Figure 22. HF SWIR equalisation results SWIR LEFT: mid-August



Figure 23. HF SWIR equalisation results SWIR CENTER mid-August



Figure 24. HF SWIR equalisation results SWIR RIGHT mid-August



Figure 25. HF SWIR equalisation results SWIR LEFT: mid-September



Figure 26. HF SWIR equalisation results SWIR CENTER: mid-September



Figure 27. HF SWIR equalisation results SWIR RIGHT: mid-September



1.5. Experimental vignetting/strip non-uniformity analysis

Methodology

PROBA-V TOA reflectance measurements over desert sites are compared against OSCAR model simulations. The comparison is done on a pixel/column averaged basis for non-projected data instead of using ROI averaged data and this for the full SWIR strip. For each valid SWIR strip we obtain :

𝛥𝐴𝑖𝑆𝑊𝐼𝑅 = 𝜌𝑇𝑂𝐴,𝑖

𝑆𝑊𝐼𝑅,𝑃𝑟𝑜𝑏𝑎𝑉 𝜌𝑇𝑂𝐴,𝑖𝑆𝑊𝐼𝑅,𝑚𝑜𝑑𝑒𝑙⁄ with i the pixel number

Next, the results are normalized by the average value over the FOV :

∆Ā𝑖, 𝑛𝑜𝑟𝑚𝑆𝑊𝐼𝑅 =∆Ā𝑖𝑆𝑊𝐼𝑅

𝑎𝑣𝑔(∆Ā𝑖𝑆𝑊𝐼𝑅)

This highly experimental methodology was set-up during the commissioning phase to correct for clear over-corrected vignetting artifacts at the edge of SWIR detectors. The methodology is however very prone to errors due to site non-uniformity (there are no natural sites which are bright in SWIR and fully homogeneous over the whole SWIR strip) and BRDF effects. The difficulty lies in discriminating small systematic instrument strip non-uniformities from the noise (such as site and BRDF effects) The methodology is currently being applied to the SWIR strips covering Libya-4, Arabia1 and Sudan sites.



Results The analysis is currently still ongoing. Therefore only very preliminary results are given. In the figure below we illustrate observed non-uniformities with a representative SWIR strip image over Libya-4 (the red arrow indicates the region of observed non-unifomity) and we plot the derived ∆Ā𝑖, 𝑛𝑜𝑟𝑚𝑆𝑊𝐼𝑅 for the different scenes (with red circle the area of non-uniformity is marked). Although we selected only the most homogenous

scenes, these ∆Ā𝑖, 𝑛𝑜𝑟𝑚𝑆𝑊𝐼𝑅 do contain a lot of ‘scene’ related discontinuities. This shows that it will be very complex to derive accurate equalisation values for the correction of the non-uniformities. The analysis of large amount of scenes will be needed.

Strip/Camera Example Libya-4 strip (vertical lines relate to identified bad pixels)

∆Ā𝑖, 𝑛𝑜𝑟𝑚𝑆𝑊𝐼𝑅 𝑓𝑜𝑟 𝑠𝑒𝑣𝑒𝑟𝑎𝑙 𝑖𝑚𝑎𝑔𝑒𝑠

Left SWIR2



Left SWIR3

Center SWIR2



Center SWIR3

Right SWIR1



1.6. Radiometric ICP file The updates to the radiometric ICP file used within the user segment for the processing of the nominal PROBA-V data by PF are listed in the table below

ICP filename Description

PROBAV_X_R_000_20140116_01.xml Update of offset and NL values provided by OIP at end of the commissioning phase

PROBAV_X_R_000_20140215_01.xml Update of VNIR and SWIR dark currents

PROBAV_X_R_000_20140219_01.xml Update of SWIR equalizations

PROBAV_X_R_000_20140322_01.xml Update of VNIR and SWIR dark currents , SWIR status map update : one bad pixel added

PROBAV_X_R_000_20140419_01.xml Update of VNIR and SWIR dark currents , SWIR status map update : five bad pixel added

PROBAV_X_R_000_20140529_01.xml Update of VNIR and SWIR dark currents , Update of SWIR equalizations

PROBAV_X_R_000_20140626_01.xml Update of VNIR and SWIR dark currents ,update of absolute blue CENTER and RIGHT

PROBAV_X_R_000_20140718_01.xml Update of VNIR and SWIR dark currents , Update of SWIR equalizations

PROBAV_X_R_000_20140826_01.xml Update of VNIR and SWIR dark currents , Update of SWIR equalizations, SWIR status map update : two bad pixels added

PROBAV_X_R_000_20140923_01.xml

Update of absolute calibration coefficient BLUE LEFT, NIR LEFT, RED CENTER, Update of VNIR and SWIR dark currents, Update of SWIR equalizations, SWIR status map updated: one bad pixel added.

PROBAV_X_R_000_20141025_01.xml

Update of absolute calibration coefficient NIR RIGHT. Update of VNIR and SWIR dark currents , Update of SWIR equalizations, SWIR status map updated : one bad pixel added.

PROBAV_X_R_000_20141108_01.xml Update of SWIR equalizations, SWIR status map updated : three bad pixels added.

PROBAV_X_R_000_20141129_01.xml Update of VNIR and SWIR dark currents , Update of SWIR equalizations.



PROBAV_X_R_000_20141220_01.xml Update of VNIR and SWIR dark currents (using for SWIR DC acquisitions with IT of 3 s) , Update of SWIR equalizations.

PROBAV_X_R_000_20141220_02.xml* Update of SWIR dark currents (using DC acquisitions with IT of 0.6s). Update SWIR equalization coefficients.

PROBAV_X_R_000_20141220_03.xml**

Update of SWIR dark currents (using DC acquisitions with IT of 0.2s). Update of absolute calibration coefficient of RIGHT SWIR3. SWIR status map updated : four bad pixels added. Update SWIR equalization coefficients.

PROBAV_X_R_000_20150311_01.xml Update of SWIR dark currents (using DC acquisitions with IT of 0.2s)




PROBAV_X_R_000_20150630_01.xml Update of VNIR and SWIR dark currents

PROBAV_X_R_000_20150724_01.xml Update of SWIR dark currents

PROBAV_X_R_000_20150826_01.xml Update of SWIR dark currents. Update of absolute calibration parameter of RIGHT SWIR2 strip.



PROBAV_X_R_000_201509*_01.xml Update of SWIR dark currents, and absolute calibration coefficients SWIR strips (except Right SWIR3)

* created on January 23 with a validity date in the past, ** created on February 13 with a validity date in the past

Table 6: Radiometric ICP-file updates



2. Geometric Image Quality

2.1. Summary We noticed a degradation of the geometric error during the period 03/07/2015 – 09/07/2015 (see Figure 29). This error has gradually increased from 50 m up to a maximum of 100 m for the Blue and Red spectral bands. The peak occurred in 07/07/2015. It is difficult to assess the cause of this sudden degradation of the geometric performance. This degradation is observed for the Blue and Red and with a less impact on the NIR and the SWIR bands. This indicates a common cause for all of them. However since the 09/07/2015, a new geometric ICP file was generated and made operational from the 09/07/2015. The new ICP file was able to reduce the geometric error by a factor 2 (from 100 m to 50 m). This behaviour is seen starting from the applicability date 10/07/2015 (see Figure 29). Apart from the period where the geometric degradation is observed, the average daily average location error compliance (ALE<300m) was stable and at the level of 99%. The inter-band geometric accuracy remained stable and ranged from 28 m to 50 m (std~= 14 m). The inter-band error is stable compared to the result reported in the previous reporting period. In this reporting period the multi-temporal geometric accuracy was at the level of 89% for the VNIR sensor and 97% for the VNIR/SWIR combined. This results is better than the previous reporting period for the VNIR and stable for the VNIR/SWIR combined. A new ICP file has been created on the 09/07/2015 to correct for the degradation of the geometric performance observed beginning of July 2015.



2.2. Assessment of the geometric accuracy on L1C data The absolute location error (ALE) of the Level1C data is presented in the table below for each camera, spectral band/strip and reporting month.

CAMERA 1 Mean ALE (m)

Strip\Period 16/06/2015 - 15/07/2015 16/07/2015 - 15/08/2015 16/08/2015 - 15/09/2015

BLUE 93.55, std = 65.80 61.41, std = 57.56 68.42,std = 72.18

RED 98.50, std = 69.25 66.96, std = 65.92 73.26, std = 75.87

NIR 89.53, std = 52.31 60.96, std = 46.66 62.30, std = 50.75

SWIR1 116.68, std = 71.44 80.09, std = 59.60 78.56, std = 56.73

SWIR2 72.30, std = 24.28 45.47, std = 20.41 43.95, std = 18.77

SWIR3 58.90, std =20.43 44.01, std = 17.90 47.68, std = 17.73

Table 7: Mean absolute location error for camera 1.


Strip\Period 16/06/2015 - 15/07/2015 16/07/2015 - 15/08/2015 16/08/2015 - 15/09/2015

BLUE 73.40, std = 61.27 56.91, std = 57.53 58.42, std = 55.67

RED 64.46, std = 49.65 53.89, std = 49.12 53.51, std = 49.52

NIR 56.63, std = 27.58 44.32, std = 28.55 46.34, std = 27.48

SWIR1 48.90, std = 18.06 38.40, std = 16.37 40.34, std = 16.20

SWIR2 43.40, std = 15.17 34.07, std = 13.79 36.69, std = 13.07

SWIR3 53.98, std = 19.79 45.30, std = 18.99 47.06, std = 18.23



Strip\Period 16/06/2015 - 15/07/2015 16/07/2015 - 15/08/2015 16/08/2015 - 15/09/2015

BLUE 79.06, std = 56.29 59.74, std = 51.05 59.25, std = 49.72

RED 71.92, std = 43.80 54.66, std = 45.12 55.00, std = 42.49

NIR 68.17,std = 32.47 51.43, std = 29.56 51.94, std = 30.26

SWIR1 56.45, std = 20.03 41.74, std = 18.18 42.30, std = 17.16

SWIR2 57.79, std = 18.82 41.43, std = 17.60 40.46, std = 15.27

SWIR3 113.45, std = 116.47 86.17, std = 98.63 90.48, std = 100.04


In the reporting period, we noticed a degradation of the geometric performance for the 3 camera (ALE around 80 m to116m). The degradation period is from the 03/07/2015 till the 09/07/2015 and more visibile for the left camera 1 (see table aboves). The same degradation is observed on the Level2 products (see next section). Excluding that period, the geometric performance is well within the requirements (ALE ranging from 40 to 90m).



2.3. Assessment of the geometric accuracy on L2 data

2.3.1. Absolute geometric accuracy

The daily summary of the L2 data absolute location error for all spectral bands is presented in the tables and figures below for the three reporting months:

from 16/06/2015 to 15/07/2015

from 16/07/2015 to 15/08/2015

from 16/08/2015 to 15/09/2015 The tables list:

The day of the measurement in format dd/mm/yyyy

The daily achieved compliance (%B) for the BLUE band (% of GCP where ALE<=300m)

The daily achieved compliance (%R) for the RED band (% of GCP where ALE<=300m)

The daily achieved compliance (%N) for the NIR band (% of GCP where ALE<=300m)

The daily achieved compliance (%S) for the SWIR band (% of GCP where ALE<=450m)

The number of GCP per day (NB-B) used to derive the absolute location error ALE for the BLUE band

The daily average ALE (in m) for the BLUE band (MU-B)

The daily ALE standard deviation (in m) for the BLUE band (STD-B)

The number of GCP per day (NB-R) used to derive the absolute location error ALE for the RED band

The daily average ALE (in m) for the RED band (MU-R)

The daily ALE standard deviation (in m) for the RED band (STD-R)

The number of GCP per day (NB-N) used to derive the absolute location error ALE for the NIR band

The daily average ALE (in m) for the NIR band (MU-N)

The daily ALE standard deviation (in m) for the NIR band (STD-N)

The number of GCP per day (NB-S) used to derive the absolute location error ALE for the SWIR band

The daily average ALE (in m) for the SWIR band (MU-S)

The daily ALE standard deviation (in m) for the SWIR band (STD-S)



Day %B %R %N %S NB-B MU-B STD-B NB-R MU-R STD-R NB-N MU-N STD-N NB-S MU-S STD-S

16/06/2015 99.75 99.81 99.80 99.95 23091 51.33 38.93 28530 49.12 37.15 25948 47.96 35.09 25943 49.51 40.21

17/06/2015 99.84 99.86 99.89 99.97 34047 53.57 37.25 39417 53.31 46.77 34256 51.03 42.85 31072 53.21 43.76

18/06/2015 99.82 99.82 99.82 99.96 25960 54.32 45.87 31988 55.01 41.96 25780 50.45 43.39 26599 52.46 38.30

19/06/2015 99.85 99.80 99.79 99.94 26710 52.77 40.21 32170 52.47 45.08 27626 49.40 43.79 29460 52.70 46.05

20/06/2015 99.78 99.89 99.92 99.94 25210 54.40 43.12 31356 53.19 47.70 29615 49.80 35.98 30318 53.87 43.13

21/06/2015 99.88 99.93 99.92 99.98 24934 51.60 35.20 31770 51.73 37.59 29204 49.67 41.65 30069 55.02 38.86

22/06/2015 99.74 99.72 99.73 99.96 26987 56.43 43.53 33309 55.32 39.36 29962 56.72 38.42 30510 61.67 46.64

23/06/2015 99.80 99.79 99.76 99.94 22345 58.86 43.61 27653 57.81 41.44 23425 59.03 46.70 23857 63.46 46.99

24/06/2015 99.74 99.78 99.74 99.93 21548 56.09 44.55 26927 55.87 46.16 23929 57.05 47.30 25628 59.82 46.04

25/06/2015 99.80 99.84 99.81 99.98 26420 50.48 38.24 32490 51.46 42.17 30031 50.06 44.19 30428 50.72 41.72

26/06/2015 99.62 99.65 99.73 99.93 19259 51.76 45.33 24374 52.51 51.69 20251 48.90 39.89 20707 51.24 44.73

27/06/2015 99.85 99.91 99.89 99.97 21400 55.40 41.72 27505 55.89 41.38 26375 53.01 37.73 27436 53.13 42.07

28/06/2015 99.85 99.91 99.87 99.92 17927 56.02 47.04 21013 56.51 54.40 20559 54.80 48.11 19785 57.80 49.19

29/06/2015 99.69 99.71 99.72 99.93 24943 55.51 41.21 30874 55.35 43.35 29575 53.16 47.43 28251 57.72 48.69

30/06/2015 99.75 99.77 99.81 99.93 26268 56.57 43.25 30177 55.70 49.95 26249 53.02 46.63 25203 55.18 54.34

01/07/2015 99.82 99.86 99.87 99.95 24746 55.15 48.16 31209 54.76 44.67 30789 51.50 40.79 29193 52.91 44.63

02/07/2015 99.69 99.81 99.85 99.98 21958 59.82 47.27 27615 59.57 50.12 29275 54.07 42.02 25743 53.68 41.91

03/07/2015 98.84 99.30 99.63 99.92 21938 88.86 70.98 26721 87.63 67.65 28771 77.32 60.65 26598 73.92 57.93

04/07/2015 98.94 99.33 99.67 99.94 21648 93.16 63.98 26975 92.77 65.71 28097 79.64 57.58 27895 72.76 51.88

05/07/2015 99.20 99.32 99.57 99.93 22883 88.01 66.22 27888 88.20 64.03 26566 77.63 57.41 26678 70.79 53.57

06/07/2015 99.24 99.41 99.58 99.94 19761 92.40 70.52 24583 92.83 64.47 23453 80.87 60.87 23508 71.96 54.49

07/07/2015 98.65 98.92 99.44 99.94 18495 103.22 75.82 23324 99.93 71.40 22362 85.21 63.96 21645 75.83 59.04

08/07/2015 99.12 99.20 99.39 99.92 22609 90.23 71.13 27691 89.37 72.96 25277 77.66 63.96 25251 73.63 59.65

09/07/2015 99.39 99.74 99.73 99.93 24619 67.87 61.25 29243 59.96 46.42 23244 59.94 48.79 24567 61.04 55.36

10/07/2015 99.84 99.85 99.89 99.95 21823 51.18 44.71 25591 50.68 39.40 26278 48.38 39.66 25527 53.74 41.97

11/07/2015 99.79 99.82 99.82 99.90 20885 56.91 51.60 25745 55.51 47.19 26263 52.67 44.09 24451 57.31 49.80

12/07/2015 99.54 99.72 99.76 99.93 22624 67.25 57.83 27745 66.56 57.04 26381 62.31 53.06 24811 64.95 56.04

13/07/2015 99.27 99.54 99.56 99.95 22911 72.96 64.38 27937 70.87 57.07 27068 68.07 53.82 27478 66.12 54.24

14/07/2015 99.15 99.58 99.57 99.96 22365 82.41 59.60 27314 82.89 57.55 27584 74.02 61.48 26079 77.63 56.33

15/07/2015 99.45 99.60 99.69 99.95 20067 73.85 60.78 24596 74.97 57.13 24246 67.38 54.15 24435 68.60 54.37

Average 99.55 99.673 99.74 99.94 23212.70 65.27 51.443 28457.66 64.59 50.96 26614.63 60.024 48.04 26304.16 60.74 48.73

Table 10: Daily achieved compliance and the daily average location error (in m) for all spectral bands in the period 16/06/2015 to 15/07/2015.



Figure 29: Daily average location error for all spectral bands in the period from 16/06/2015 to 15/07/2015 (left). The average daily compliance of the spectral bands (right).




16/07/2015 99.42 99.61 99.63 99.94 26277 67.89 54.96 30670 68.97 58.97 26178 61.13 51.96 26115 62.86 52.30

17/07/2015 99.75 99.76 99.85 99.97 25935 61.18 47.37 30916 61.33 44.80 26537 55.22 41.77 27745 57.21 44.78

18/07/2015 99.73 99.80 99.78 99.96 27087 54.17 42.06 32554 54.03 43.49 27739 49.40 38.63 30657 55.44 44.87

19/07/2015 99.84 99.88 99.86 99.98 26415 50.66 47.91 32070 50.58 38.27 27350 46.69 34.82 28612 53.04 42.40

20/07/2015 99.73 99.75 99.76 99.95 23067 50.21 39.48 27265 49.34 51.50 24297 48.60 38.68 25562 52.39 45.85

21/07/2015 99.64 99.73 99.67 99.93 22489 60.01 48.24 27295 57.52 47.48 24381 56.62 50.58 24791 60.78 46.85

22/07/2015 99.73 99.79 99.75 99.97 24759 55.92 42.52 30325 54.35 44.54 29069 51.21 39.10 27779 56.06 42.30

23/07/2015 99.90 99.87 99.87 99.97 22742 47.10 35.18 26772 46.64 42.91 22423 45.08 33.20 23425 51.01 43.61

24/07/2015 99.77 99.89 99.92 99.99 10475 49.19 39.43 9118 50.21 39.43 8363 47.38 37.82 6892 48.61 34.63

25/07/2015 N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A







01/08/2015 99.85 99.83 99.79 99.93 72700 34.56 45.39 38774 56.32 48.14 33327 56.27 52.38 36002 58.11 54.97

02/08/2015 99.76 99.78 99.80 99.97 25012 54.80 51.47 31131 54.76 46.00 29568 52.26 47.72 31747 54.76 41.48

03/08/2015 99.68 99.80 99.82 99.96 25942 56.10 49.93 31198 55.60 51.45 29209 53.48 45.20 30484 55.21 44.47

04/08/2015 99.91 99.70 99.70 99.84 143412 44.69 24.11 35866 58.50 60.16 30398 55.75 51.99 32411 59.38 57.38

05/08/2015 99.77 99.81 99.81 99.94 27043 49.79 40.49 32935 49.74 40.48 28969 48.11 36.57 31984 51.11 45.37

06/08/2015 99.86 99.88 99.92 99.94 24219 51.25 37.40 30709 50.05 39.22 27507 47.76 36.26 30375 52.44 44.68

07/08/2015 99.81 99.82 99.84 99.93 22801 56.44 43.35 28862 53.33 47.31 26462 49.19 38.99 28548 55.58 46.94

08/08/2015 99.77 99.88 99.86 99.97 24538 51.99 38.45 31056 50.29 42.77 28651 47.03 35.27 29978 52.07 41.48

09/08/2015 99.75 99.66 99.72 99.87 82487 50.54 44.88 44551 53.26 57.43 36940 48.29 55.47 39487 53.55 55.61

10/08/2015 99.77 99.85 99.91 99.97 20794 52.41 43.33 26248 53.12 45.10 25545 47.56 33.03 26214 55.79 42.40

11/08/2015 99.81 99.89 99.90 99.97 23653 53.42 40.94 29852 53.13 42.59 28503 52.48 42.22 31296 55.49 45.00

12/08/2015 99.82 99.80 99.83 99.95 23971 51.73 39.82 29672 52.62 39.91 28109 50.56 44.83 29032 55.81 43.03

13/08/2015 99.80 99.83 99.83 99.96 32262 52.38 40.44 36278 52.38 39.69 33010 51.40 38.49 34581 55.26 41.20

14/08/2015 99.78 99.84 99.79 99.95 32236 49.62 43.77 36477 50.92 46.85 34313 48.29 43.04 36786 53.87 49.88

15/08/2015 99.78 99.85 99.85 99.91 36099 48.08 54.15 40757 47.27 41.87 34301 45.88 41.14 37592 50.73 49.57

Average 99.76 99.80 99.81 99.94 34434 52.25 43.12 31306.30 53.51 45.84 27964.50 50.65 42.04 29504 54.85 45.87




Figure 30: Daily average location error for all spectral bands in the period from 16/07/2015 to 15/08/2015 (left).

The average daily compliance of the spectral bands (right).




16/08/2015 99.81 99.82 99.82 99.93 25896 48.73 50.68 31413 48.11 49.63 29210 47.29 49.30 30683 50.32 44.37

17/08/2015 99.67 99.77 99.81 99.94 29568 53.36 47.32 34710 52.00 44.53 33400 49.53 40.03 31822 54.74 43.73

18/08/2015 99.81 99.89 99.90 99.96 30642 51.36 42.26 36912 49.18 40.86 36746 46.73 37.00 35096 53.22 42.89

19/08/2015 99.80 99.87 99.86 99.97 31729 48.48 44.00 40803 46.83 36.98 39967 44.90 37.05 38749 50.16 41.75

20/08/2015 99.79 99.81 99.86 99.95 29309 54.55 48.60 37644 56.23 47.52 36733 51.25 42.33 36876 57.85 47.04

21/08/2015 99.34 99.57 99.50 99.80 55520 61.72 77.37 70596 62.35 73.10 71719 57.84 64.91 69168 65.35 69.97

22/08/2015 99.16 99.34 99.35 99.76 48920 61.89 87.13 64811 62.38 77.58 75051 56.71 68.37 72185 66.08 73.59

23/08/2015 99.35 99.55 99.57 99.81 50858 60.49 80.28 67276 58.56 70.03 80239 54.59 59.39 78230 62.51 67.95

24/08/2015 99.33 99.51 99.53 99.79 48039 58.64 81.80 64485 57.39 68.01 72703 54.82 66.68 71829 60.95 67.49

25/08/2015 99.02 99.33 99.43 99.76 41740 67.29 89.11 56069 65.07 78.80 69118 59.73 69.62 69614 64.42 72.24

26/08/2015 99.25 99.50 99.55 99.84 45699 62.95 82.13 57949 59.67 71.26 70991 55.58 62.55 71118 59.83 66.62

27/08/2015 99.22 99.40 99.43 99.83 45412 60.19 86.15 58730 58.22 74.32 66949 56.04 70.83 66910 60.26 66.49

28/08/2015 99.33 99.53 99.51 99.79 49567 56.34 75.17 63392 54.26 66.10 71666 52.80 65.55 72706 58.58 70.36

29/08/2015 99.37 99.57 99.55 99.80 47985 57.07 81.98 62332 54.97 66.49 71829 52.73 65.33 71321 59.17 68.11

30/08/2015 99.37 99.46 99.45 99.77 49452 62.82 77.82 62647 60.00 70.64 63312 58.95 66.45 66539 64.99 74.47

31/08/2015 98.91 99.20 99.20 99.77 45670 81.42 87.72 58105 76.68 70.31 64424 78.47 73.23 64346 82.30 72.06

01/09/2015 99.06 99.33 99.33 99.82 46100 81.75 81.78 58870 78.11 68.98 67982 80.53 67.28 70337 81.65 69.93

02/09/2015 99.38 99.58 99.44 99.76 55388 59.31 74.75 68641 54.95 65.77 74910 58.75 70.47 77031 62.28 71.31

03/09/2015 99.27 99.40 99.49 99.80 51386 60.94 81.47 59128 58.60 74.33 69257 54.32 65.80 67057 59.83 67.66

04/09/2015 99.20 99.51 99.59 99.81 48701 65.11 83.99 57429 61.32 70.82 72679 55.79 62.64 70237 61.47 67.47

05/09/2015 99.23 99.45 99.50 99.79 50459 65.94 79.32 62910 64.63 71.01 78421 57.91 64.24 77856 65.06 69.73

06/09/2015 99.11 99.26 99.26 99.81 49413 70.93 80.25 55535 73.07 74.61 68733 65.90 69.64 70197 70.27 74.05

07/09/2015 98.87 99.16 99.23 99.76 48115 78.34 86.80 52525 78.07 78.91 64950 71.05 69.89 62903 75.93 76.29

08/09/2015 99.10 99.19 99.30 99.79 45447 77.15 85.68 49978 77.42 79.59 64435 69.10 72.90 63720 74.41 72.44

09/09/2015 99.14 99.37 99.47 99.83 53445 67.66 86.32 58243 65.97 72.98 72002 60.37 60.77 71935 65.24 63.87

10/09/2015 99.14 99.41 99.46 99.83 52366 65.36 81.35 60363 62.65 65.62 70014 57.92 64.28 67895 63.45 65.71

11/09/2015 99.31 99.56 99.56 99.82 55734 61.02 80.96 65100 58.54 58.95 74933 54.76 60.56 74762 60.37 65.01

12/09/2015 99.30 99.38 99.40 99.80 57430 58.52 85.86 64044 57.59 71.36 71328 55.12 63.35 71682 59.82 68.19

13/09/2015 99.12 99.35 99.45 99.79 56187 61.63 82.74 64102 60.44 72.65 70264 57.90 65.23 71282 63.07 71.48

14/09/2015 99.22 99.46 99.46 99.81 41787 64.30 86.96 48148 61.80 70.13 51473 59.75 61.44 53337 65.78 69.12

15/09/2015 99.07 99.33 99.33 99.77 45403 66.30 82.71 52986 65.62 70.32 56100 62.38 64.30 56666 68.81 74.07

Average 99.29 99.47 99.50 99.82 46237.60 62.95 76.78 56318.60 61.31 66.84 63920.60 58.04 61.98 63680.30 63.48 65.66




Figure 31: Daily average location error for all spectral bands in the period from 16/08/2015 to 15/09/2015 (left). The average daily compliance of the spectral bands (right).



During the period from 25/07/2015 till 31/07/2015, no geometric statistics are available. This is mainly due to some minor issues/bugs in the geometric validation scripts. These bugs are already fixed and the validation scripts are consolidated and made more robust to avoid this interruption in the future. The total number of chips per day and per spectral band used for the geometric accuracy analysis has increased by 30% on average when comparing to the previous the reporting period. The daily average location error compliance (ALE<300m) was at the level of 99.7%. This result is comparable to what is stated in the previous reporting period.

The monthly average location error remained below 60.5 m for all spectral bands (combined cameras) for the reporting period. Variation in the average location error is relatively small (1σ standard deviation < 60m) and correlated for all spectral bands (similar trends can be observed in the left part of Figure 29, Figure 30 and Figure 31). This indicates that the geometric inter-band error between the spectral bands is stable and low (see next section).

2.3.2. Inter-band geometric accuracy

The monthly average inter-band geolocation error for all combinations of spectral bands was as follows:

Band pair Inter-band error [m]

BLUE-RED 28.58 std=7.78

BLUE-NIR 44.15 std=12.31

BLUE-SWIR 50.20 std=14.22

RED-NIR 35.51 std=13.91

RED-SWIR 43.67 std=12.33

NIR-SWIR 44.27 std=10.61

Table 13: Inter-band geolocation accuracy for period 16/06/2015 to 15/07/2015 stated for combined cameras, at 95% confidence level.





RED-NIR 32.02 std=11.81










RED-NIR 31.68 std=11.04




For combined cameras the inter-band geometric accuracy remained stable and ranged from 28 m to 50 m (max std ~= 14 m). This result is comparable to the result reported in the previous reporting period.

2.3.3. Multi-temporal geometric accuracy

During this reporting period the compliance of the multi-temporal geometric accuracy was at the level of:

89.91% for the VNIR sensor (205604 GCPs used),

97.55% for the VNIR/SWIR combined (227077 GCPs used).

This compliance level has increased when comparing to the previous reporting period ( 83.3% for the VNIR sensor). For the VNIR the multi-temporal geometric accuracy is below the requirements of 95%. A map of regions with decreased multi-temporal geometric accuracy is presented in Figure 32.

Figure 32: Multi-temporal geometric accuracy for the VNIR sensor. Compliant areas are marked in green; areas with accuracy below 95% are marked in red. Grey areas represent no data. (period

from16/06/2015 till 15/09/2015).



2.4. Geometric ICP file A new ICP file has been created on the 09/07/2015 to correct for the degradation of the geometric performance observed beginning of July 2015.

ICP filename Description

PROBAV_ICP_GEOMETRIC#LEFT_20150704_V001 PROBAV_ICP_GEOMETRIC#CENTER_20150704_V001 PROBAV_ICP_GEOMETRIC#RIGHT_20150704_V001

Correct for the degradation observed beginning of July 2015.

Table 16: Geometric ICP-file updates

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