Precise station positions from

VLBI observations to satellites –

a simulation study

Lucia Plank1, Harald Schuh2,

Johannes Böhm1,

Geodätische Woche 2013 | 8-10 October 2013 | Essen, Germany

1Vienna University of Technology, Austria 2GeoForschungsZentrum GFZ Potsdam, Germany

2

DFG FOR 1503

PN4 PN1

Barycentric

ephemeris

PN3

Moon related

systems

PN6

Datum definition

and dynamic

satellite orbits

PN5

Consistent celestial

and terrestrial

reference frames

PN7

Co-location on

Earth and in space RISE Project Group

Measurement Data

SELENE, SELENE-2, Chang‘e-1, Chang‘e-2, YH

Mars Orbiter

V. Tornatore

Data & Knowledge

GNSS-VLBI

PN4 Ties between kinematic

and dynamic reference

frames (D-VLBI)

DFG Research Unit:

Space-Time Reference Systems for Monitoring Global Change and for Precise

Navigation in Space

3

Motivation

4

Space tie

5

New observations

• Geodetic Reference Antenna in

Space (GRASP)

• Mission concept presented to

NASA in 2011

• Bar-Sever et al 2009

• Mini-Satellite mission @ GFZ

• Micro-GEM, Brieß et al 2009

• NanoX

• Observations of GNSS

satellites

• Tornatore et al 2011

6

VLBI to spacecrafts

• Routinely done in spacecraft navigation • Differential (D-) VLBI

• Sensitive perpendicular to line of sight

• Link between ICRF and dynamic Ephemerides

• NASA, ESA, JAXA

• Used for planetary science • Lunar mission SELENE

• Tracking of Mars Express, Venus Express,

Huygens Probe

• Various technical realizations • Single-target vs. D-VLBI

• Different signal (frequency)

• Group delay vs. phase delay

7

New processing

GEODETIC VLBI

• plane wave front

• stable sources

SPACECRAFT VLBI

• curved wave front

• fast moving sources

• time of emission t0

8

VieVS2tie software

Plank et al 2013

9

VLBI to LAGEOS

• 16-stations network

• 6000 km height

• 1 minute observation interval

• Weekly solution

7 d

= 1.3 cm

10

VLBI to GRASP2000

• 32-stations network

• 2000 km height

• 30 sec observation interval

• Weekly solution

7 d

= 1.2 cm

11

VLBI to GRASP2000

• regional 6-stations network

• 2000 km height

• 1 minute observation interval

• Weekly solution

7 d = 0.6 cm

Good results in dense

regional networks

Network effect

12

Observing the GPS

• Satellite constellation (6 sat)

• ~20200 km height

• 1 minute observation interval

• Global R1 session (24-h)

• Combined solution

IVS-R1594

16JUL13

13

Frame tie

14

Frame tie

15

Frame tie

rms after 1 day

Translation

x

Translation

y

Translation

z

Rotation

x y, z Scale

R1 0.4 mm 0.6 mm 0.1 mm 0.0 µas 0.5 ppb

Helmert parameters

16

Conclusions

• VLBI satellite tracking to improve the ITRF

• Implementation in the Vienna VLBI software (VieVS,

Böhm et al 2012) allows simulation of VLBI satellite

observations

• Weekly solutions for satellite-only observations

• Troposphere is limiting factor

• The combined approach allows the determination

of frame ties between the GPS and the VLBI frame

at the sub-millimeter level in the Helmert

parameters for standard 24-h sessions

17

lucia.plank@tuwien.ac.at

THE END Thank You for listening! D-VLBI

DFG Research Group FOR 1503

Bar-Sever et al 2009, COSPAR Colloquium Padua, Italy 2009

Böhm et al 2012, IAG Symposia Series Vol. 136, Proc 2009 IAG Buenos Aires

Brieß et al 2009, MicroGEM Abschlussbericht Phase 0/A, GFZ Potsdam and TU Berlin

Eubanks 1999, Proc US Naval Observatory Workshop on Relativistic Models for Use in Space Geodesy

Klioner 1991, Proc AGU Chapman Conf, NOAA Tech Rep NOS 137 NGS 49

Pany et al 2010, J Geod

Plank et al 2013, Proc 21st EVGA 2013, Reports of the Finnish Geodetic Institute 2013:1

Tornatore et al 2011, ETTC 2011, European Test and Telemetry conference