SDP interfaces for real-time data exchange

Introduction

At AA0.5 the SDP needs to be able to exchange data with other telescope subsystems in real-time for:

• Publishing Jones matrix calibration solutions for the CBF to form tied-array beams;
• Obtaining the actual pointing of Mid dishes;
• Publishing pointing offsets for Mid following a reference pointing observation (in near-real time).

This data will be exchanged with other subsystems via Tango device attributes, and the devices will communicate with the processing pipelines (which are the sources and sinks of the data inside SDP) over the data queues. It may require the development of specialised Tango devices for this purpose.

The aim of this feature is make an initial implementation of the interfaces that can be configured via the SDP control system, and demonstrate that the data exchange works with mocked data sources and sinks.

The real-time beamformer gain and pointing offset calibration pipelines are being developed separately (see SP-2556, SP-2899 and SP-2745). It will be the work of a subsequent feature to plumb them together with the Tango devices via the data queues.

Who?

• SDP developers.
• Control system developers.

What?

• Provide Tango devices implementing interfaces for exchanging real-time data with other subsystems.
• Interfaces are configurable via the SDP control system.
• Demonstration of the interfaces using mocked data sources and sinks.

Why?

• Essential piece of functionality for communicating in real time with other telescope subsystems.

References

• AA0.5 scenarios, see beamformer and pointing scenarios.
• SDP schemas (version 0.4) for specifying Tango attribute names (see also ADR-54 for background).