LOFAR2.0 Newsletter March 2020

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After a relaxing end of year period, the LOFAR2.0 development is in full swing again. It is fantastic to see the commitment and progress over the breadth of the system. With so many activities in parallel, mutual coordination and clarity about responsibilities is crucial at this stage, also for your own peace of mind! In case of uncertainties or issues contact your project manager or work package leader directly. It is also important to continue celebrating our successes. I have asked Patricia to create a visible place where we can share and celebrate our small and big successes. More details will be announced soon. And of course make sure that you submit your highlights to the ASTRON/JIVE daily image as well!

Wim van Cappellen

Telescope Manager

Marcel Loose

The Telescope Manager subsystem is currently in "low power state", due to the fact that priority has been given to the architectural design of the Station software and the overarching design of parts of the Monitoring & Control system and Telescope Manager.

Fortunately, the long-awaited restart of the LOFAR Efficiency Improvement project (LEI) finally took place. The project was relabelled as Telescope Management Specification Subsystem (TMSS) and covers about 80% of TM. The software architect for TM works in close collaboration with the TMSS team to ensure that efforts are properly aligned.

TMSS

Roberto Pizzo

TMSS (Telescope Manager Specification System) is developing a new software application for the specification, administration, and scheduling of LOFAR observations. This is crucial, as the current LOFAR toolchain is slowing down LOFAR innovations. A lack of automation in the operation and maintenance of LOFAR currently demands high levels of support and the current software design makes new software expansions expensive to realise.

Rebuilding the current software with a new design and new technology will have important benefits:

Support for LOFAR2.0 use cases;
More efficient LOFAR operations;
Improved adaptability and maintainability of software to be able to realise its extensions.

TMSS is part of the Telescope Manager of LOFAR2.0, the system that will control all aspects of the telescope, including proposal handling, observation execution, and system monitoring.

By the end of 2020, TMSS will deliver with high priority the software components for executing the LOFAR Survey Use Cases. By doing that, the project will implement also other LOFAR Science Use Cases, which will ensure a healthy continuation of the Cycle observing programs also before the start of the LOFAR2 surveys.

The TMSS project started in January. The development of TMSS is realised using an agile approach, where product features are planned and realised in three-weekly sprints. Additionally, a quarterly cycle has been introduced. The objectives of each cycle are set to realise specific system enhancements in well-defined areas. The first quarter will implement the TMSS foundations: telescope model and database. During the first two sprints we have successfully delivered the login interface and the specification system for DUPLLO Imaging Survey observations. During the first Cycle, the system will be further enhanced to perform the survey observations with the required handling of and feedback on system resources. The following cycles will implement dynamic scheduling functionality, support for the other planned use cases and responsive telescope functionality.

Systems engineering in LOFAR2.0

Hans van der Marel

Large and complex systems such as the LOFAR2.0 telescope have many interfaces, both to the external world and internally between subsystems and components. It is very important that the interfaces are taken into account at an early stage of the designs in order to avoid late and expensive changes.

Within LOFAR2.0 the approach for the interfaces is to start describing an interface as soon as it has been identified. This happens in Polarion where the Interface Control Documents (ICDs) are maintained, containing special work items for the description of external and internal interfaces. The interfaces usually lead to requirements for the interfacing systems or subsystems and these requirements are becoming part of the requirements specification for that (sub)system. The requirements are linked to the interfaces to allow easy checking which requirements are belong to a certain interface. As design work progresses to more detailed design, the interface descriptions become more detailed, as well as which products are actually interfacing and what requirements that poses on the products.

For interfaces with external users or systems, discussions with external parties are needed to fill in the ICDs. At the moment the ICD with the station stand-alone users is an ICD which gets a lot of attention, as this may have a significant impact on the station software. The removal of the post-processing pipelines and other functionality to SDC will result in an extended ICD.

LOFAR4SW

Carla Baldovin

LOFAR4SW has been preparing at full speed for the detailed design review (DDR) to be held at ASTRON on March 23 and 24. The review will focus on the design of the HBA dual beam tile and the functional design of simultaneous observing software.

Members of the team from ASTRON, Nancay, Bielefeld, Chalmers, and UKRI (WP4, WP5, WP6) have been working long hours to prepare the documentation.

Our team revisited the prioritisation of the use cases, a long-standing exercise in our project, and has come up with a plan for a modular implementation of LOFAR4SW that will also be presented at the review. A panel of experts from ASTRON, U. of Twente, INAF, and Chalmers were given the enormous responsibility of reviewing our design.

The DDR is an important milestone in LOFAR4SW; it represents the last chance to make any significant changes to the design that will continue to be developed towards the next major milestone: the critical design review planned for early 2021. In addition, the documentation to be reviewed will be submitted to the EC as part of the project deliverables.

The team in LOFAR4SW looks forward the DDR meeting and the exchange with the panel of experts. Stay tuned! The outcome of the review will be covered in the next edition of this newsletter.

Station

Johan Boekema

After completing the PDR, the LOFAR2.0 Station is working towards the Detailed Design and Critical Design. Within the project there are a 5 work packages to ensure the timely delivery of the designs of the sub-systems. The heart-beats of these work packages differ, i.e. some work packages plan in periods of 6 to 12 weeks and other work packages plan in periods of 3 weeks.

This means that the project approach is a combination of waterfall, Kanban and SCRUM. This combination is a new phenomenon within ASTRON but allows us to manage the long-term goals within the project as well as the short term sub-deliveries. This approach combined with the System Engineering approach will ensure the delivery of the test stations, detailed design and reaching our milestones at the right time.

Architecture

André Gunst

A functional diagram of the LOFAR2.0 “Execute Observations” function is created. Such a diagram shows the connections and the order of the functions. The “Execute Observations” function covers all functions necessary to transform the radio signal to the desired data products.

Figure 1 shows the functions which are mapped on the station sub-system, while Figure 2 shows the functions which are covered by the CEP sub-system. The rectangles with dashed lines show connections with other functions. The AND operator is used to show functions which need to run simultaneously, while the OR operator indicates that one of the paths is active at the same time.

Figure 1 Part 1 of the functional diagram of the “Execute Observations” function in LOFAR2.0.

Figure 2 Part 2 of the functional diagram of the "Execute Observations" function in LOFAR2.0.

COBALT2.0 phase 2

René Kaptijn

In COBALT2.0 Phase 1 we upgraded the hardware of the COBALT GPU cluster. COBALT2.0 phase 2 will upgrade the COBALT software to prepare for the “LOFAR Mega Mode” (LMM) which will enable simultaneous observations serving half a dozen scientific surveys and space weather applications, greatly increasing the efficiency with which LOFAR is used for scientific research.

The PMP for COBALT2.0 Phase 2 is almost ready for approval. The project team is almost complete and plan is to start phase 2 on March 1st. The team will use the Agile SCRUM method. Functionality prioritised by the product owner is put on the backlog. The development team will implement the functionality in 3-weekly sprints.

The work is split up in three blocks of 2-3 months. The last block is planned to be ready by April 2021.

Timing Distributor (TD)

René Kaptijn

Timing Distributor is the realisation of a central clock for all Dutch LOFAR stations using White Rabbit technology.

For Timing Distributor the predecessor CSYLOPHON project terminated at 31 January 2020. The project continues as Timing Distributor under the DUPLLO proposal.

We are currently creating the PMP. Main objective of the project is to get the White Rabbit central clock technology into the current LOFAR as soon as possible. This to reduce risks for the other LOFAR2.0 projects (e.g. the STAT(ion) project).

In February we plan the first test observations with four LOFAR stations connected to a central clock via White Rabbit technology. More measurements and investigations have to be performed and the documentation has to be updated according to the PDR remarks.

In a first draft schedule we plan the CDR in September 2020. In Q4 a tender is planned (White Rabbit and network equipment purchase). Then after the delivery period the roll-out and commissioning are planned in the first half of 2021.

LOFAR2.0 Newsletter March 2020

Telescope Manager

Marcel Loose

TMSS

Roberto Pizzo

Systems engineering in LOFAR2.0

Hans van der Marel

LOFAR4SW

Carla Baldovin

Station

Johan Boekema

Architecture

André Gunst

COBALT2.0 phase 2

René Kaptijn

Timing Distributor (TD)

René Kaptijn

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