1

Validation and assessment of space debris orbits based

on two-color and multi-static laser tracking data

C. Bamann1, U. Hugentobler1, J. Eckl4, S. Riepl4, U. Schreiber1, F. Sproll2, D. Hampf2,

W. Riede2, G. Kirchner3, F. Koidl3, M. Steindorfer3

October 14, 2016

1Technical University of Munich, Research Facility Satellite Geodesy 2German Aerospace Center, Institute of Technical Physics, Stuttgart 3Austrian Academy of Sciences, Sprace Research Institute, Graz 4Bundesamt für Kartographie und Geodäsie, Wettzell

Research Facility Satellite Geodesy (FESG) Department of Civil, Geo and Environmental Engineering Technical University of Munich

1. Available data from tracking campaigns

2. Orbit determination

3. TLE based data filtering and initialization

4. Validation

a) Kinematic single-pass solutions

b) Cross-validation

c) Consistency bi-static ranges with mono-static data

5. Summary and next steps

Outline

3

1. Available data Tracking campaign 1

Overview

August 13-27

32 objects successfully tracked

54 passes

Mostly typical space debris objects

(~80% spent rocket bodies)

NORADID WETTZELL GRAZ STUTTGART(BI)

3230 2 1 0

4327 2 0 0

14372 2 0 1

14699 1 0 0

14820 1 0 0

15772 3 1 0

16182 3 0 1

16496 2 0 0

16792 0 1 0

17291 0 1 0

17589 1 0 0

19120 0 1 0

19573 3 0 1

19650 1 0 0

20466 1 0 0

21574 0 2 0

22285 1 0 0

23087 1 0 1

23405 1 0 0

23560 0 1 0

24953 1 0 0

25163 0 1 0

25263 0 1 0

25621 0 1 0

27386 1 2 2

28059 1 1 0

28931 0 1 0

36417 0 1 0

37390 0 1 0

37731 0 1 0

37789 0 1 0

38043 0 1 0

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1. Available data Tracking campaign 2

Overview (1)

NORADID WETTZELL GRAZ GRAZ(BI) STUTTGART(BI)

733 1 0 0 0

5560 7 1 0 4

8459 1 0 0 2

10967 1 1 0 0

14699 1 0 0 1

15483 2 1 0 2

16615 0 2 0 0

16792 1 0 0 0

16882 4 2 1 1

17129 0 1 0 0

17590 1 0 0 2

17973 4 1 0 3

18187 2 1 1 2

19650 1 0 0 1

20466 0 0 0 1

21088 1 0 0 0

21610 4 1 2 0

22220 5 3 2 1

22286 1 0 0 2

22566 4 4 2 3

22803 1 0 0 1

23088 6 2 2 3

23548 1 0 0 0

23705 1 0 0 3

24298 4 2 1 0

24946 1 0 0 1

24953 0 1 0 0

25407 2 1 0 5

25860 1 0 0 1

27386 1 2 1 4

28521 1 0 0 0

31793 2 0 0 4

36417 0 1 0 0

37731 0 1 0 0

39271 4 1 1 2

September 7-14

35 objects successfully tracked

(More than) 162 passes

Mostly typical space debris objects

(~80% spent rocket bodies)

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1. Available data Tracking campaign 2

Overview (2)

- Objects for which all “types“ of observations are available

- Black background indicates favourable temporal distribution of data

- All objects are rocket bodies except 27386 = Envisat (some pre-processing

issues to be solved)

NORADID WETTZELL GRAZ GRAZ(BI) STUTTGART(BI)

16882 4 2 1 1

18187 2 1 1 2

22220 5 3 2 1

22566 4 4 2 3

23088 6 2 2 3

27386 1 2 1 4

39271 4 1 1 2

7 objects , 67 passes

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1. Available data Tracking campaign 2

Temporal distribution (1)

16882 07.Sep 08.Sep 09.Sep 10.Sep 11.Sep 12.Sep 13.Sep 14.Sep

Wettzell X X X X

Graz X X

Grazbi X

Stuttgartbi X

18187 07.Sep 08.Sep 09.Sep 10.Sep 11.Sep 12.Sep 13.Sep 14.Sep

Wettzell X X

Graz X

Grazbi X

Stuttgartbi X X

23088 07.Sep 08.Sep 09.Sep 10.Sep 11.Sep 12.Sep 13.Sep 14.Sep

Wettzell XX X X X X

Graz X X

Grazbi X X

Stuttgartbi X X

39271 07.Sep 08.Sep 09.Sep 10.Sep 11.Sep 12.Sep 13.Sep 14.Sep

Wettzell XX X X X

Graz X

Grazbi X

Stuttgartbi X X

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1. Available data Tracking campaign 2

Temporal distribution (2)

22220 09.Sep 10.Sep 11.Sep 12.Sep 13.Sep 14.Sep

Wettzell X X X X X

Graz X X X

Grazbi X X

Stuttgartbi X

22566 09.Sep 10.Sep 11.Sep 12.Sep 13.Sep 14.Sep

Wettzell X XX X

Graz X X XX

Grazbi X X

Stuttgartbi X X X

Successful multi-static tracking campaign

Near-circular ~800 km orbits

8

SL-16 R/Bs (Zenit second stages) SL-8 R/Bs (Kosmos 3M second stages)

1. Available data Object characteristics

Diameter 3.9 m

Length 10.4 m

Dry mass 8300 kg

Diameter 2.4 m

Length 6.0 m

Dry mass 1400 kg

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1. Available data Object relevance

Liou, J-C. "Active debris removal-a grand

engineering challenge for the twenty-first

century." (2011).

Estimated parameters in orbit determination process:

1. 6-elements state vector

2. Atmospheric drag coefficient (Cd)

3. Solar radiation pressure coefficient (Cr)

4. Station range biases

5. Station clock offsets for bi-static ranging data

Not estimated:

1. Empirical accelerations reliance on dynamics model

2. Time dependent station range biases (assumed constant)

Force models: Higher-order gravity, aerodynamic drag (DTM-2000), solar radiation pressure,

luni-solar perturbations (DE-430), solid Earth tides, Albedo

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2. Orbit determination

Depending on amount and

distribution of data

1. Noisy bi-static ranging data

2. Very inaccurate TLE data (sometimes too far from true orbit to initialize orbit determination

local minima)

3. TLE data improvement based on single-pass tracking data

kinematic single-pass solutions

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3. TLE based data filtering and initialization (1)

𝑥𝑡𝑙𝑒 + Δ𝑥𝑡𝑙𝑒

𝑥𝑡𝑙𝑒

Δ𝑥𝑡𝑙𝑒 𝑡 = 𝑅 𝑡 ⋅ 𝑝𝑅 𝑡 − 𝑡0 + 𝐼 𝑡 ⋅ 𝑝𝐼 𝑡 − 𝑡0 + 𝐶 (𝑡) ⋅ 𝑝𝐶 𝑡 − 𝑡0

𝑝𝑅 𝑡 − 𝑡0 = 𝑎𝑅,0+𝑎𝑅,1 𝑡 − 𝑡0 +𝑎𝑅,2 𝑡 − 𝑡02+…

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3. TLE based data filtering and initialization (2)

Basis for noise filtering (2.x-sigma clipping)

Used to initialize orbit determination

Validation of high frequency components (jitter, noise, object shape,...)

Derivation of force model coefficients from historical TLEs (if not estimated)

0 1 2 3 4 5 6 7 8

minutes since start of pass [min]

-200

-150

-100

-50

0

50

100

150

200

on

e-w

ay r

an

ge

re

sid

ua

ls [

m]

kinematic orbit adjustment - two constant parameters

Graz initial

Graz adjusted

Wettzell initial

Wettzell adjusted

Assessment of post-fit residuals

1. Kinematic single-pass solutions

noise and high-frequency signal components

2. Cross validation (consistency of omitted data with orbit)

range prediction accuracy

3. Bi-static range residuals (incl. station clock offset estimation)

consistency with mono-static ranging data

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4. Validation

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4. Validation Kinematic orbits

Post-fit residuals (Wettzell)

0 50 100 150 200 250 300 350 400 450

seconds of pass [s]

7.5

-5

-2.5

0

2.5

5

7.5

on

e-w

ay r

esid

ua

ls [

m]

object 22220 (SL16-R/B) - kinematic orbit residuals - Wettzell

0 20 40 60 80 100 120 140

seconds of pass [s]

-7.5

-5

-2.5

0

2.5

5

7.5

on

e-w

ay r

esid

uals

[m

]

object 15483 (SL8-R/B) - kinematic orbit residuals - Wettzell

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4. Validation Kinematic orbits

Post-fit residuals (Graz)

0 50 100 150 200 250 300

seconds of pass [s]

-2.5

-2.0

-1.5

-1.0

-0.5

0

0.5

1.0

1.5

2.0

2.5

on

e-w

ay r

an

ge

re

sid

ua

ls [

m]

object 22220 and object 22566 - kinematic residuals (NPT) - Graz

0 10 20 30 40 50 60 70 80 90

seconds of pass [s]

-2.5

-2.0

-1.5

-1.0

-0.5

0

0.5

1.0

1.5

2.0

2.5

on

e-w

ay r

ang

e r

esid

ua

ls [m

]

object 16882 (SL-8 R/B) - kinematic residuals (NPT) - Graz

0 6 10 15 20 25 30 35 40 45 50

hours since reference epoch [h]

-50

-40

-30

-20

-10

0

10

20

30

40

50

on

e-w

ay r

an

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re

sid

ua

ls [

m]

object 22566 - mono-static ranging Graz + Wettzell - reference epoch: 2016-09-12

only orbit

orbit + Cd + Cr

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4. Validation Reference solution (mono-static data)

Post-fit residuals (1)

22566 12.Sep 13.Sep 14.Sep

Wettzell X XX X

Graz X X XX

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4. Validation Cross-validation (mono-static data)

Post-fit residuals (2)

22566 12.Sep 13.Sep 14.Sep

Wettzell X XX X

Graz X X XX

cross-validation cross-validation

45.50 45.75 46.00 46.25 46.50 46.75 47.00 47.25 47.50 47.75

hours since reference epoch [h]

-80

-60

-40

-20

0

20

40

60

80

on

e-w

ay r

an

ge

re

sid

ua

ls [

m]

object 22566 - passes from 2016-09-14

-0.15 -0.1 -0.05 0 0.05 0.1 0.15 0.2 0.25

hours since reference epoch [h]

-60

-40

-20

0

20

40

60

on

e-w

ay r

an

ge

re

sid

ua

ls [

m]

object 22566 - passes from 2016-09-12

0 50 100 150 200 250 300 350 400 450 500

seconds since start of pass [s]

-50

-40

-30

-20

-10

0

10

20

30

40

50

on

e-w

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an

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sid

ua

ls [

m]

object 22220 - Wettzell + Graz (mono-static) - reference epoch: 2016-09-12

1st day for validation

3rd day for validation

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4. Validation Cross-validation (mono-static data)

Post-fit residuals (3)

2016-09-12 passes

Graz

Wettzell

14.Sep 22220 12.Sep 13.Sep 14.Sep

X Wettzell X X X

XX Graz X X X

14.Sep 22220 12.Sep 13.Sep 14.Sep

X Wettzell X X X

XX Graz X X X

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4. Validation Bi-static data issues

Bi-static range residuals - Stuttgart (1)

47.00 47.02 47.04 47.06 47.08 47.10 47.12 47.14 47.16

hours since reference epoch [h]

-175

-150

-125

-100

-75

-50

-25

0

25

50

75

100

ran

ge r

esid

ua

ls [

m]

object 22566 - mono-static ranging wettzell and graz - bi-static ranging stuttgart

mono-static ranges (bi-static in solution)

mono-static ranges (bi-static not in solution)

bi-static data (not in solution)

bi-static data (not in solution)

22566 12.Sep 13.Sep 14.Sep

Wettzell X XX X

Graz X X XX

Stuttgartbi X X X

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4. Validation Bi-static data issues Bi-static range residuals - Stuttgart (2)

47.00 47.02 47.04 47.06 47.08 47.10 47.12

seconds since start of pass [m]

-20

-10

0

10

20

30

40

50

ran

ge r

esid

ua

ls [

m]

object 22566 - mono- and bi-static ranging

mono-static ranging data

bi-static ranging data

Summary

1. Useful data available for validation activities from two tracking campaigns

2. One-way ranging “noise“ within expected bounds

3. Data is suitable for orbit determination and prediction as indicated by first validation tests

Next steps:

• GNSS-based clock synchronization and data filtering of bi-static data from Graz

• More tests with bi-static data / understanding the effects seen in first processing

• Assessing the benefits from multi-static tracking

• Further cross-validation tests; also for objects with less data

• Processing Envisat data and validation w.r.t. to external reference orbit

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5. Summary and next steps