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A Strategic Mission Planning Concept for
TerraSAR-X Conflict avoidance instead of
conflict resolution
M. Wickler A. Braun, M. Geyer, C. Foussal DLR
Oberpfaffenhofen 82330 Wessling,
Germany Martin.Wickler_at_dlr.de www.dlr.de
www.gsoc.dlr.de
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Overview

• TerraSAR-X Mission
• TerraSAR-X planning problem
• Existing planning approach
• New planning approach
• Priority concept
• Conclusion

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Overview about the TerraSAR-X satellite

• One satellite, equipped with (payload)
• X-band radar (transmitter receiver), 3
  different prime modes (scan, strip, spot)
• High precision GPS
• for observation of the earth
• Geo info (Crop stand, Topographic Map,
  Infrastructure Planning Map, Flood Damage
  Assessment, Geology Structure Map)
• Ship detection service oil spill monitoring
• Traffic investigations (ships, cars)
• Telecom planning / utility planning
• Launch date April 2006

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Overview about the TerraSAR-X mission

• Orbit-Parameters
• Sun-synchronous repeat orbit
• High precision repeat orbit 11 days period,
  250m cross-track
• Local equatorial Crossing time 18.00hrs 0.25h
  ascending pass
• Nearly polar orbit, altitude at equator 514.8km
• Bottle-neck resources
• 1 uplink station for commanding (WHM)
• 1 downlink station for data reception (NGS)
• Thermal constraints for a maximum of 500
  datatakes/day ( ca. 50 min/day)
• Onboard memory for max. 3min of datatakes
  (dependant on radar mode)
• Onboard command buffer

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Overview about the TerraSAR-X users

• TerraSAR-X project is a PPP (public private
  partnership) between DLR and EADS (Astrium /
  Infoterra). Therefore heterogeneous user groups
  have access rights to use TerraSAR-X
• Commercial user group (represented by InfoTerra)
• Scientific user group (represented by DLR)
• Radar-system calibration and experimental group
  (represented by DLR)
• First estimations by these user groups result in
  an average system overload of ca. 100 (gt1000
  datatakes / day).
• Requirements for a data take could be
• Single orders
• Coverage orders (consisting of gt100 single
  datatakes)
• Standing orders (repeated single / coverage
  orders)

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Existing Mission Planning approach (1)

• The common mission planning task consists of
• Collecting requirements (for datatakes) and
  availabilities (of the system)
• Generate a feasible / optimized plan (considering
  all constraints)
• Distribute plan
• This would lead for TerraSAR-X to the following
  tasks for a 1-day look-ahead plan Find a
  good (the best) solution 500 datatakes of 1000
  requests for a 7-day look-ahead plan Find a
  good (the best) solution 3500 datatakes of 7000
  requests for a 1-month look-ahead plan Find
  a good (the best) solution 15000 datatakes of
  30000 requests

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Existing Mission Planning approach (2)

• Depending on the requirements profile, as a
  minimum 50 of all requests could NOT be planned
  (due to the overall amount of requests and
  conflicting orders). gt 50 of the user
  (customer) must be informed that their order
  could NOT be performed
• Depending on the planning concept (daily, weekly,
  monthly), any information (planned or
  not-planned) could be given only a day, a week or
  a month in advance.
• The planning task is very challenging (e.g.
  find the best 1500 data takes out of 3000) and
  the result leads not to a real customer
  satisfaction (gt50 negative reply)

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TerraSAR-X Mission Planning approach (1)

• The following main goals should be established
• Maximum customer satisfaction
• Maximum relationship of performed/ordered
  datatakes
• Fast feedback between user and Mission Planning
• Cost effective operations / planning
• Low man-power budget (nearly autonomous planning)
• High availability

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TerraSAR-X Mission Planning approach (2)

• To reach these goals, the existing mission
  planning scenario was extended by introducing the
  following innovations
• A Priority Concept
• An online ordering and preview system with user
  feedback

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Priority concept (1)

• Basics for the TerraSAR-X priority concept
• Establishing a strategic planning group
• Members are Representatives of all user groups,
  the mission management and a mission planning
  representative
• The strategic planning group meets periodically
  (e.g. monthly)
• Main tasks
• Analysis of existing order status
• Definition of the mission goal (for the upcoming
  time frame)
• Definition of certain limitation of orders for
  each user group (quotas)
• Definition of a set of rules / principles
• Definition of the priorities and fixing who is
  allowed to use them
• Definition of the formula to calculate the needed
  points dependant on the specific parameters of
  the order criteria
• Definition of rules in case of conflict (e.g.
  first come first serve)

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Priority concept (1) cont.

• Basics for the TerraSAR-X priority concept
• The usage of a quotation, dependant on certain
  order criteria
• Priority of the order (from 1 (low) up to 9
  (highest))
• Radar-mode (reflecting datatake duration and
  onboard resource usages)
• Number of single datatakes (to fulfill coverage
  or standing orders)
• Time-point of each order (early ordering is
  cheaper than a late one)
• Implementing a software (apportionment control
  mechanism) controlling and handling the overall
  process (no human involvement)

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Priority concept (2)

• The priority concept in detail
• The strategic planning group allocates a certain
  amount of the TerraSAR-X system to each user
  group. (Sub-user-groups are possible)This
  allocation is represented by an individual
  account of points.(The weighting factors of
  the point-calculation-formula are defined as
  well.)
• Each order is represented (via the pre-defined
  formula) by a certain number of points.
• For each online ordering process, the
  apportionment control system checks the
  availability of points.
• Depending on the capacity utilization and the
  user needs the strategic planning group
  (p)re-defines the mission goal for the next time
  and re-allocates the individual quota.

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Priority concept (3)

• Mutual dependencies of the MPS modules

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Priority concept (4)

• Functional overview

Order feasible? y/n
Order possible? y/n
Order parameter
Mission Planning System
Project specific checks
Online order-preview (quick feasibility check)
Order-check (extended feasibility check)
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Advantages

• The users get all information about the
  feasibility, the status and status changes of
  each order immediately (on-line).
• The priority of an order is given by the user
  (-group) itself. This enables the user to
  enforce the Mission Planning System to
  guarantee the performance with the related
  probability. (High priority high probability to
  be performed)Maximum customer satisfaction.
• The number of overall orders is limited to a
  meaningful amount with respect to the
  (bottle-neck) resource availabilities.
• Possible conflicts are avoided in advance instead
  of solving them during the original planning
  process.

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Conclusions

• This priority concept avoids conflicts in advance
  instead of resolving them during final mission
  planning.
• This reduction is granted by a sophisticated
  reduction of requests and an on-line involvement
  of the users/ customers.
• Such a concept is suited for each kind of
  planning with different groups / interest of
  users.
• This concept is baselined in a dedicated
  TerraSAR-X document and signed by all parties.