LEDAS  
Leicester Database and Archive Service
 
Mission
    Description
Products
    Databases
Raw Data
    Archive
Analysis Software
    Archive
Ginga Information
Ginga Gallery
Related Sites
Databases
GINGALAC
GINGABGD
GINGAFRF
GINGALOG
GINGAMODE
GINGARAW
View Ginga DBs
Line
Footer
e-mail
Downtime expected shortly as all LEDAS services are moved to a new server.

Temperature Dependence of the Ginga Clock Rate

John E. Deeter1 and Hajime Inoue2

[1]Department of Astronomy, University of Washington
[2]Institute of Space and Astronautical Science

Abstract:

The period of the clock aboard Ginga varies by one part in 106, mainly due to a strange temperature dependence with a maximum near 18°C. This temperature dependence makes it difficult to assign times of observation to the data with millisecond accuracy, particularly during remote orbits during which it is not possible to compare the onboard clock with a reference clock at the Kagoshima ground station. In this paper we investigate the relationship between satellite temperature and clock period, and show how this relationship can be used to estimate the clock period from the temperature data even when direct clock comparisons are not available. The resulting corrected times of observations are accurate to 2-3 milliseconds, even during remote orbits. We show that with some simple precautions this method can be used to achieve 100 µs accuracy in time assignment for Astro D, without actively controlling the clock temperature with an oven.



[]
 
HOME
SEARCH
SERVICES INFO SOFTWARE ViZieR BLASTA DSS
ARCHIVES ASCA CHANDRA GINGA ROSAT ARNIE