F O T O SFeasibility study forOptical Tracking Of Satellites

GNOSIS Precision SSA Workshop

9 July 2020

Thomas Wijnen Remko Stuik

Michiel Rodenhuis Marco Langbroek

Petra Wijnja

(TU Delft, RNLAF) (Leiden Observatory) (Leiden Observatory) (Leiden Observatory) (RNLAF)

Instrument

FoV: 53 x 74 degrees24 x 36 mm interline CCD24 mm f/1.4 Canon lens

Credit: G.-J. Talens

-Subtract 2 images

Observations

Reduction

Line recognition

Line fitting

Orbit determination

Precision & quality

Method

-Data reduction

1. Subtract 2 consecutive images

-Data reduction

1. Subtract 2 consecutive images

-Data reduction

1. Subtract 2 consecutive images

-Data reduction

1. Subtract 2 consecutive images

-Data reduction

1. Subtract 2 consecutive images

-Data reduction

2. Mask the stars

1. Subtract 2 consecutive images

-Data reduction

2. Mask the stars3. Enhance the tracks

1. Subtract 2 consecutive images

-Data reduction

I. Binary image with pixel values > μ + 2.5 σII. Binary image with pixel values > μ + 1 σIII. Dilate 2.5 σ image IV. Multiply diluted with 1 σ imageV. Convolution to check for ≥6 adjacent nonzero pixels

2. Mask the stars3. Enhance the tracks

-Line recognition

• Hough transform

-Line recognition

• Hough transform

-Line recognition

• Hough transform

-Line recognition

-Line fitting

1. Ransac

-Line fitting

1. Ransac

-Line fitting

1. Ransac

-Line fitting

1. Ransac

-Line fitting

1. Ransac2. Determine endpoints

-Line fitting

1. Ransac2. Determine endpoints

-Line fitting

1. Ransac2. Determine endpoints

-Line fitting

1. Ransac2. Determine endpoints

-Line fitting

1. Ransac2. Determine endpoints

-Line fitting

1. Ransac2. Determine endpoints

-Line fitting

1. Ransac 2. Determine endpoints

-Line fitting

Orbit determination

-

Orbit determination

-1. Gauss method (6 sky coordinates to 6 orbital elements) 









Orbit determination

-1. Gauss method (6 sky coordinates to 6 orbital elements) 









Orbit determination

-1. Gauss method (6 sky coordinates to 6 orbital elements) 









Orbit determination

-1. Gauss method (6 sky coordinates to 6 orbital elements) 









Orbit determination

-1. Gauss method (6 sky coordinates to 6 orbital elements) 









Orbit determination

-1. Gauss method (6 sky coordinates to 6 orbital elements) 









Orbit determination

-1. Gauss method (6 sky coordinates to 6 orbital elements) 









Orbit determination

-1. Gauss method (6 sky coordinates to 6 orbital elements) 









2.Least square fitting to SGP4 propagation

Predict second passage -Precision & Quality

'unknown' TLE

known TLE

Averaged over 1 night -Precision & Quality

'unknown' TLE

known TLE

�4 �2 0 2 4Time to local midnight [hours]

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50

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300

350

400N

sat

Passed LEO satellites

Found LEO satellies

Selectivity

�4 �2 0 2 4Time to local midnight [hours]

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cent

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Selectivity

�4 �2 0 2 4Time to local midnight [hours]

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Selectivity

Take-away points

• Simple, low-cost set-up (not dedicated to SSA)


• Able to automatically detect satellites & 
 determine orbital parameters 


• Large fraction of objects in LEO is recognised 


• Satellites with unknown TLE’s require multiple passages

•

FOTOS2

FOTOS2

Refinement New techniques

FOTOS2

Refinement New techniques

Build on & refine MASCARA/bRing data & routines

FOTOS2

Refinement New techniques

Build on & refine MASCARA/bRing data & routines

GEO satellites with BlackGEM

Full field:13x Full Moon

Two geostationary satellites as seenby BlackGEM proto-type MeerLICHT: Thor 5 & 6

BlackGEM spatial resolution@ GEO orbit: 170m

26 kilometer!

FOTOS2

Refinement New techniques

Build on & refine MASCARA/bRing data & routines

GEO satellites with BlackGEM

FOTOS2

Refinement New techniques

Build on & refine MASCARA/bRing data & routines

GEO satellites with BlackGEM

Characterisation with spectro(polari)metry

FOTOS2

Refinement New techniques

Build on & refine MASCARA/bRing data & routines

GEO satellites with BlackGEM

Characterisation with spectro(polari)metry

NEO