The first prototypes of the Alma Common Software (ACS) and the Antenna Mount Software (AMS) have been tested in December at Kitt Peak with the 12m antenna. IRAM is involved in both developments.
ACS will provide a set of tools and services to be used in all Alma applications. The software is based on distributed objects, configuration database, logging and error systems, It adds a layer on top of CORBA to implement the distributed objects architecture.
It is the prototype of this layer (or ``wrapper'') which was tested at Kitt Peak. The applications and the graphical user interfaces are developed in C++, JAVA and Tcl/Tk (the latter is an alternative for fast prototyping). IRAM's contribution has been to test specifically the Tcl language mapping for CORBA and to check Tk as a quick and attractive way to develop user interfaces accessing CORBA services.
The version of AMS developed by IRAM and NRAO provides very simple functionality. It uses ACS to implements the objects and their methods, both defined conjointly between ESO, IRAM and NRAO in IDL (Interface Desciption Language).
Its architecture is build around several loops, and uses messages and events which are available through the object-oriented framework and toolkit ACE (Adaptive Communication Environment). The benefit of CORBA and ACE is to have a portable software: AMS has been developed and tested on Linux, with the antenna simulation and the Graphical User Interface (GUI) in Tcl/Tk running on the same machine. With the 12m antenna AMS has been executed on VxWorks on a VME Motorola CPU board installed in a chassis with either the same GUI or another interface written in JAVA, both executed on Linux. AMS employs SLALIB, the positional astronomy library developed at Rutherford Appleton Laboratory.
At Kitt Peak, all functions defined in the interface have been tested.
They include positions in horizontal or equatorial coordinates,
offset, tracking, drift and pointing model.
It has been possible to calculate the coefficients
(limited to 6) of the pointing model by using the optical camera mounted
on a telescope finder. The corrections have been processed by
TPOINT, widely distributed pointing model analysis package by P.T. Wallace.
The result of the pointing session was a blind pointing
accuracy of the order of 7
rms.