Observing a GPS Satellite Maneuver with MW and SLR

Astronomical Institute, University of Bern

Claudia Urschl

Astronomical Institute, University of Bern 2

Experiment history

• Maneuver announced for May 17, 2005 between 20:30 - 08:10 UT

• Request for tracking via e-mail to SLR stations (ilrssta)

• Maneuver took place at 22:28 UT• Bad weather conditions• Only Herstmonceux (7840) tracked

GPS35 during the maneuver• Fullrate data (148) 22:11 – 23:08 UT

Maneuver for GPS satellite GPS35

Astronomical Institute, University of Bern 3

First orbit solution

Maneuver at 22:28:17

Astronomical Institute, University of Bern 4

First orbit solution (zoom)

Maneuver

Astronomical Institute, University of Bern 5

Ground track GPS35

ManeuverCHUR

KOUR

KIRU

GOPE

7840

Astronomical Institute, University of Bern 6

First orbit solution

t = 234 s

Astronomical Institute, University of Bern 7

Improved orbit

Maneuver

Astronomical Institute, University of Bern 8

Maneuver evaluation

Orbit determination: a = 0.88 mm/s2

t = 234 s

Assumption: m = 975 kg

vGAS = 200 m/s

v = a • t

F = m • a

MGAS = v / vGAS • m

v = 0.2 m/s

F = 0.86 N

MGAS = 1 kg

Astronomical Institute, University of Bern 9

GPS Satellite Maneuvers since 2004

May 17