Scheduling Tool for ESTRACK Ground Station Management

Transcription

1 Tool for ESTRACK Ground Station Management W. Heinen Rhea System S.A. NewTechCenter, Avenue Einstein a, B-48 Louvain-La-Neuve, Belgium M. Unal ESA/ESOC, Robert Bosch Str. 5, 649 Darmstadt, Germany The ESA Station Tracking Network (ESTRACK) comprises a set of general purpose and deep space ground stations. The ESOC is in charge of scheduling station activities for more then 0 missions over 40 ground station terminals. currently uses a scheduler tool that collects centrally requests from missions and constraints from ground stations. The scheduler disseminates the edited station allocations back to the missions. This tool performs basic constraints & health checks but leaves conflict resolution as a manual operator task. ESOC are developing the ESTRACK Management System () that intends to enhance operations of ESA's tracking network by a largely automated planning and scheduling process for the various ground segment resources, and remote operations at the station network level. This paper will summarize how the scheduler has been used to support phase-in of to an operational environment minimizing impacts, in particular on missions that run legacy systems. I. Introduction A. Functioning of the The ESOC is the central point for the collection and allocation of ground station activities within ESA. It collects information from the core and augmented ESA stations as well as for cooperative stations, such as the NASA DSN Stations. This means that, even that the station configuration process is not entirely within the responsibility of the, it has the knowledge of all station allocations and disseminates this data to the various missions. The has been developed and introduced in 004 to automate many operational procedures within scheduling office and to channel all sources of information into one consistent dataset. B. The MOIS Toolset ESOC missions use a toolset called MOIS, to prepare operations activities, in particular the operations procedures. MOIS has traditionally been used to produce the formal Flight Operations Plan (FOP), a printed, configuration controlled document set and it produces from these procedures executable procedures for the mission control system. The that is part of the MOIS Toolset is a Mission Planning tool. For its mission application, it is configured to pre-plan all routine platform and payload operations and it generates a schedule of on-board time tagged commands that are up-loaded during each ground station pass by the FCT. The MOIS scheduler ensures the Rhea System S.A. NewTechCenter, Avenue Einstein a, B-48 Louvain-La-Neuve, Belgium. ESA/ESOC, Robert Bosch Str. 5, 649 Darmstadt, Germany

2 overall consistency of a consolidated set of Payload Operations together with Flight Dynamics and Spacecraft Operations using and checking against Flight Dynamics Events, Ground Station Availabilities and other resources. Conceptually, there are clear parallels between the planning of payload activities and planning of station allocations. Bearing this in mind, the scheduler has been adapted for the requirements. C. The ESTRACK Management System () In order to reduce operation costs and improve the utilisation of resources the European Space Operations Centre has started to implement systems that will enable the automation of mission operations. One of these systems is the, a suite of applications that support the automated planning and scheduling and the centralised coordination of ESA s ESTRACK network. The ESTRACK network comprises all the ESA facilities deployed around the world in order to provide the tracking services required by the Agency and its customers. The increase of missions to be supported on limited resources, the increasing need for interoperability and the evolution towards ever more mission specific tracking service requirements have driven the requirements for an automated planning and scheduling and global network monitoring and control system. II. in the ESOC infrastructure This section gives a short overview of the entities that communicate with the scheduler. The numerous inputs are Station schedule files TNOC schedule files for Svalbard Ground Station Maintenance Ground Station Support ESOC Allocation Files TECS Files containing mission requests (for a subset of missions) Santa Maria Schedules NASA Station Allocation Files NASA-SPS Station Allocations Figure. A Glance of the This source data is collected by the scheduler, consistency checked and the following products are disseminated: Activity Schedules these are summary sheets for the ECC operators that are defining the ECC daily activities based on the schedule station activity. Station Allocation Plan the allocated passes are transmitted to the Operational Service Provision Management System, a web-based tool to provide logging of operational activities by ECC to measure the service volume and service performance delivered to OPS-ONF customers. The data is furthermore used to compile Key Performance Indicators to access quality and suitability of ESTRACK. OMS Sheets they are the official allocation confirmation to the missions. These sheets are generated for each mission-station combination and they are automatically sent by to a distribution list. Web pages the same information as contained in the OMS is generated in form of web pages that are available on the ESTRACK webserver.

3 III. Phase-A Introduction of the to is being phased in progressively starting with the polar missions (ERS & Envisat), which are fairly automated and rules-based in terms of station allocation. It was therefore the best candidate for the automatic planning of the. The Kiruna S- and X-band station supports Envisat and ERS-, and is scheduled to support CryoSat-. For ESTRACK, Kiruna hosts one 5m and one m antenna. Both operate in S-band for uplink and downlink and X-band for downlink. The station is located at Salmijärvi, 8 km east of Kiruna, in northern Sweden. The station is equipped for tracking, telemetry and command operations as well as for reception, recording, processing and dissemination of data from the sensor instruments onboard ERS- and Envisat. Figure. The Kiruna Station The station is connected to the ESTRACK Control Centre (ECC) at ESOC via dedicated voice and data circuits. The station is remotely monitored and controlled from the ECC under nominal operating conditions. A mini control centre is located at the station to provide backup. On the operations side, the Scheduler had to be enhanced in order to support a progressive introduction of the. Therefore, individual stations can be marked as handled by the or not. The interface to the is added to the scheduler where firstly, all configuration data necessary for submitting valid requests can be imported. Then secondly, can import the schedule data (the plan view file) that contains the allocated passes. From the scheduler point of view, this information is handled like any other input file. A comparison enables the operators to individually reject updates and thereby still have ultimate manual control on the planning process. Any updates or rejections are issued back to the via Operational Service Session (OSS) Update. With this limited introduction of the, gains confidence and experience in the and as a result, the has been fully validated for operations. One by one, missions have been chosen to be managed by the, while the overall picture remains in the scheduler. In what concerns the missions, legacy mission control systems, mission planning systems or flight dynamics systems will not necessarily support the new direct interfaces to the. With the scheduler extension, the missions can continue to use their established scheduler link, even if from an internal station planning point of view these missions are already handled by the. The transition to the is transparent to the missions as illustrated in Figure. Envisat Compare for Envisat Rules Envisat Mission Products: OMS, Products: etc... OMS, Mission etc... Figure. Process Phase-A. The process of information exchange between and the missions remains 4naffected by the introduction of the.

4 IV. Phase-B Automation of Mission to So far, mission requests have been handled via simple exchanges or mission specific files or documents. With the legacy process, one mission using its dedicated resources, the chosen allocation was coming from the mission to the scheduling office. With the arrival of new users, the is now in charge of solving conflicts. The communication is therefore flowing in both directions to inform users of allocated tracking times. The new process is formalized in a generic document completed by dedicated mission agreements. To minimise the impact on the missions, it has been decided to provide a modified scheduler that scheduling office is using to the missions with a restricted access to its features. The scheduler can be installed locally for each mission without any infrastructure link because the exchanges are file based which makes it a distributed system. This allows the missions to visualize the plan view and enables them to make manual updates to the plan. Unlike office, where the updates are ingested into the, the missions send their updates to who is then centrally in charge of forwarding them to the. Figure 4 illustrates this process.. Issuing of the once the has terminated successfully a planning session, the plan view containing the pass allocations is issued to the mission and to scheduling office.. Import of the Once a plan has been approved and distributed by the scheduling office, the mission planner can then import the plan view into his application. A comparison window allows him to verify all changes that affect his mission prior to the update. He can also choose to import updates of the plan view for all other missions in order to have a complete view.. Issuing of Updates once the allocated passes are imported via the plan view, the mission planner can modify them on the or add new pass requests. Immediately the modified passes are marked as pending for in the application. Once finished changing, the mission planner issues the updates, i.e. OSS update request files are copied to scheduling office and also an notification is issued to a mailing list. 5 for 4 6 Notification Figure 4. Automation of Mission For Missions 4. Import of Update upon reception of the notification , scheduling office imports the requests into their current plan on the application. Similarly, a comparison window shows the changes affecting the plan prior to the import. The import of the requests will mark the affected passes as pending for. The requests validity is then checked by the scheduling office (conflict or others). 5. Including Update into the exports the valid pending requests to the from the Application. On the, a new planning session is then started with these updates. 6. Re-Issuing of the once the has terminated successfully a planning session, the plan view containing the changes to the pass allocations is issued to the mission again. Mission This architecture is very flexible in that the scheduler can be phased out once uses the directly. Missions can continue using their mission scheduler without noticeable change with the only difference that this time their requests are directly submitted to the. With this distributed system of scheduler applications, mission groups can be formed where missions can coordinate their requests before submitting them to the scheduling office by using the scheduler as an internal scheduling office function. All exchanges are file based, and as the system is distributed and not dependent on an infrastructure or network, any mission could use the Scheduler to interface to ESTRACK, without having access to the ESOC environment. Figure 5 illustrates this process. 4

5 7 6 VEX Mission for for Venus Express for Rosetta for Mars Express 5 From VEX From ROS From MEX VEX Notification 4 From ROS From MEX VEX From VEX From MEX From VEX From ROS Figure 5. Coordination between missions. Issuing of the once the has terminated successfully a planning session, the plan view containing the pass allocations is issued to the missions.. A - Import of the each mission planner imports the latest plan from the. B Import of Mission Request the mission planners import update requests from other missions that have not yet been included in the latest plan view.. Performing Updates to the Plan the mission planner can modify the passes on the or add new pass requests. The modified passes are marked as pending for. 4. Issuing of Updates once finished changing, the mission planner issues the updates. This means that the OSS update request files are copied to scheduling office and to the other missions that are in his distribution list. For the other missions, these will be the mission requests mentioned in B. Also an notification is issued. 5. Import of Update office imports the requests from the mission specific input folder into their current plan of the application. 6. Including Update into the exports the pending requests together with their updates to the from the Application. On the, a new planning session is started with these updates. 7. Re-Issuing of the once the has terminated successfully a planning session, the plan view containing the changes to the pass allocations is issued to the missions again. 5

6 V. Phase-C Planning Rules for the Missions The initial mission requirements and the agreed implementation is described in a document called Mission Agreement. It contains the description of the standing order parameters used to generate the routine planning. The has the capacity to accept derogation to existing standing orders for any given time range. This standing order refinement allows changing any number of pre-agreed parameter. Therefore, the next stage of the scheduler extension is to provide the MMI to allow these missions to influence these initial conditions of the planning process ahead of the plan view generation. These conditions can be Service Repetitions (Min, Max), Overall Duration (Min, Max), Pass Duration (Min, Max), Handover time, Service Duration and constraints on distance, event, ratio or the applicable rule. Figure 6. A Glance of the editing Planning Rules The gantt bars in yellow are standing order refinements.. Issuing of the Standing Order Refinement Templates these files contain the editable parameters that are used by an planning session. Missions import these configuration files.. Issuing of Standing Order Refinements once the mission planner has edited standing orders, he sends the updates (refinements) directly to the.. Issuing of the these refinements influence the planning session. The solution of the planning session, which is the plan view, is issued in accordance with these refinements. for S.O. Refinement Templates S.O. Refinements For Missions Mission Figure 7. Planning Rules for Missions 6

7 VI. Conclusion The is now in operation for 90% of the ESTRACK activities. The 0% missing includes exotic or highly complex requests which are still currently under specification or testing. Thanks to the combined MOIS/ approach allowing continuity of the service, the migration was never under time pressure. Maintaining the MOIS scheduler in the foreground allowed an early introduction of the in operations while keeping the capacity to fix and improve the system in its deployment phase. Any infrastructure change has to take into account legacy missions and their ability to upgrade or not. The has been introduced into the ESOC operations without imposing new interfaces to the missions. Solutions via the adaptation of the existing scheduling tool are available to the missions to automate the planning process and the access to the dataset of this new facility in a distributed system. This means that users have the capacity to migrate their system to a fully (or partially) compliant system at their own rhythm. The main drawback of a distributed system is the synchronization of multiple databases. On the other hand this duplication of data has turned out to be very convenient in case contingencies which may occur during such major change. 7