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All antennas are equipped with one inclinometer, that should allow
determination of the inclinations without astronomical pointing. Regular
monitoring of the inclinometer outputs must be made. It is especially
important to get the inclinometer results before and after each pointing
session. To use the inclinometers:
- Send an antenna North at some elevation, chosen to avoid the sun at
any
azimuth, for example using antenna Iant
$ COO ANTE Iant HO 180D 85D NULL, under DCL, or
OBS
SOURCE INCLINO, OBS
LOAD, within OBS
- Once the antenna stops, run the inclinometer program
$ INC Iant /PLOT
The antenna will do a full turn at the current elevation, and a sine curve
will be fit to the inclinations measured every 5 degrees. From this fit,
the parameters MVE and MVN are derived from the azimuth axis tilt measured
by the inclinometers using three additional corrections:
- a change of sign due to conventions on the orientation of the
vertical.
- a local vertical correction to refer the inclinations to the vertical
of the array center
- a global gravity corrections of MVE = +10", MVN = +7", to correct for
large scale deviations of the gravity field due to the Alps.
The resulting MVE and MVN are displayed and written in the file
INTER_BASE:INCLINO.ANi, where i = Iant. The fit is displayed
by GreG if you specified the /PLOT option for the INC command. A
hardcopy possibility is offered.
Next: Cookbook, Tricks, and Traps
Up: Determination of Pointing Parameters
Previous: Limited radio pointing determination
Contents
Index
Gildas manager
2014-07-01