The Data Acquisition System for the GMRT

R. K. Singh

The Giant Meterwave Radio Telescope (GMRT), an array of thirty antennas, situated at Khodad, Narayangaon, is by and large completely controlled by observers, sitting at their desks, with the help of a centralized networked system of computers at the Central Electronics Building (CEB).

The software system that achieves this can be broadly divided into two parts, (i) one that deals with the control and monitoring of the antennas (ONLINE) and (ii) one that deals with the control, monitoring as well as data acquisition (and processing) of the digital backends (DAS). Both of these systems have a large number of small embedded subsystems that can be controlled across the network. In discussion in this chapter is limited to the DAS.

Any reasonable Data Acquisition System (DAS) for the GMRT must fulfill the following major requirements.

1. Interfacing with the hardware for acquisition of data.
2. Control of the correlator both for configuration as well as required periodic updates of parameters.
3. Monitoring of the status of the correlator and flagging the data appropriately.
4. Online processing of the data for reduction and archiving.

A functional description of the GMRT correlator can be found in chapter 9, and it is assumed that the reader is familiar with it.