Autonomous EndtoEnd Planning System for TerraSARX

1
Autonomous End-to-End Planning System for
TerraSAR-X

• A. Braun, M. P. Geyer, M. Wickler, C. I. Foussal
• DLR-GSOC, Oberpfaffenhofen, D-82234 Wessling,
  Germany
• Space-Ops
• Montréal, Canada
• May, 2004

2
TerraSAR-X

• 1023 kg wet mass
• 800 W orbit average power
• Antenna 4900 x 850 x 300 mm (Lx WxH)
• 12 Antenna Panels, 384 TR-Modules
• Polarizations VV, HH, VH, HV
• 256 Gbit Mass Memory
• 300 Mbit/s Downlink in X-Band
• Launcher Dnepr-1
• Orbit SS Dusk Dawn 515 km

3
Abstract (telegram style)

• TerraSAR-X mission planning system is to
  generate safe, feasible and uncritic al timelines
• on-board spacecraft execution
• ground-station schedule
• autonomous process
• initiated by user requests
• ending with an executable command sequence.
• Several hundred data-takes per day
• orders originating from a large and multifaceted
  user community
• means for strategic planning authority to
  override automated decisions
• Customer satisfaction by
• pre-view of scenes that can be ordered
• timely feedbacks
• user decides on priority, not the project
• System load limited by
• close to truth preview for the user at ordering
• early reject of unfeasible requests
• using freedom left by the user for plan
  optimization

• Automated splitting of larger areas in single
  scenes
• optimizing for minimal make-span or minimal
  number of datatakes
• immediate branching to backup schemes if
  necessary
• Automatic scheduler
• decides on user-defined priorities
• obeying to all relevant constraints
• Outage times (orbit correction, equipment
  maintenance)
• dealing with ever changing ground segments
• DLR stations
• direct access customer stations are dealt with
• On-board resources modelled
• SAR data mass memory
• time-tag command buffer
• power/thermal model

4
Ground Segment at DLR Site in Oberpfaffenhofen
HR
data quality
radar params
swath power memory
reception status
order request
order request
timeline status
order status info
timeline payload cmd
orbit, att. ops const.
CMDs
DFD
telemetry
GSOC
5
Mission Planning Key Figures

• 11 day / 167 orbit repeat cycle dusk/dawn - 250
  m tolerance
• electronical beam steering, fixed attitude (
  roll slew for left looking)
• scan, stripmap, spot beams ? products from 5x10
  to 70x120 km
• various polarization sequences
• 35 (70) Datatakes per orbit corresp. 160 (320)
  seconds
• 300 Mbit/Sec D/L rate 4 kBit/Sec TC rate 1
  Mbyte TTC Buffer
• 256 Gbit Solid State Mass Memory, file structured
• Baseline Groundstations WHM (TM/TC) NSG (X-Dump)
• re-visit time for any point target location 4.7
  days in average (without roll slew)

6
Mission Planning Tasks

• Support Order Process
• Provide swath Preview
• Opportunity times
• check geometrical feasibility
• develop optimized scheme for complete region
  coverage
• minimal makespan (user orders) -or-
• minimal system load (background orders)
• generate satellite execution timeline
• payload Datatakes, Maintenance, (including radar
  parameters and TCs)
• bus H/K dumps, manoeuvres, maintenance
• generate ground ops timeline
• TC uplink scheme
• SAR data dump
• Support strategical planning
• data mining, decision making inputs, alternative
  options
• Feed back to user interface

7
Mission Planning Meta Constraints

• Public Private Partnership
• Strong industry participation
• Common funding
• Joint steering commitee
• Exclusive commercial exploitation
• regional providers and value adders
• 50 / 50 share between science and commercial users

8
Simulated Targets
9
Mission Planning Booking vs. Planning
simulated observation target distribution
cooperative request 2 of 350 fail
ASAP request 177 of 350 fail
10
Mission Planning Philosophy

• GOAL Maximum User Satisfaction
• Maximum user insight
• Conflict avoidance instead of conflict resolving
• Planning based on the users priority assignment
• Maximum utilization of system capabilities
• AND
• Faire Share between Commercial and Science Users
• Consequences
• positive feedback for cooperative behaviour
  needed
• means for supervision and control of quotas
• correction for systematic in-equalities
• (impatient customers are pushing vs. eternal
  truth of science can wait ?)

11
Mission Planning Point concept

• Which quota?
• Acquisition time? Data Volume? Downlink Time?
  Number of Acquisitions? Square kilometer?
  Manpower effort? Scientific profit? re-sales
  price? .....
• There are a couple of bottleneck resources,
  simultaneous quota control?
• too complicated, sub-optimal planning result,
  unfair preferences
• Map everything on-to a common scale ? calculate a
  price
• No real currency for fairness reasons, but
  points (credits, grants) distributed by the
  mission management.
• Cost functions may
• consider priority
• let the users decide on importance
• prefer early orders
• the earlier the info to arrange a schedule, the
  better system usage
• allow gap-fillers for free
• none of the orders has to be rejected for quota
  reasons

12
Mission Planning Timing
H with perf. spec. assuming 2 fold overbooking
? 6 days Tests (on simplified models) factor 20
2 passes one uplink session
13
TSX Ordering Process
Overview of OrderDesk functionality and
information flow
Status info
Status info
Status info
Status info
User order
Ok?
Production management
yes
Planning items
yes
ok?
ok?
Expand standing order
Consistency apportionment check
EOWeb (PGS)
MPS (MOS)
if needed
if needed
if required
14
Footprint database

• Controlled Orbit allows pre-calculation of all
  radar footprints for the repetition cycle
• Considers
• all available beams
• acquisition window
• digital elevation model
• used by
• swath preview
• target hit events
• coverage splitter

15
Orbit/Beam combinations available for coverage
16
Optimal and backup schemes for achieving full
coverage
Orbit
17
Planning Products
Uplink Schedule
B/U S/C exec. Timeline
S/C exec. Timeline
Key Management Facility
D/L schedule
Statistics Performance Figures
Cmd Sequences
Cmd Sequences
Cmd Sequences
Mission Manager
18
Conclusions

• Automation possible by consequent priority system
• User Satisfaction (hopefully) achieved by
• no fixed quota limitation
• priority is users own choice
• Conflict avoidance instead of deconflicting
• positive feedback to cooperative order-behaviour
• users are awarded when leaving more degrees of
  freedom
• optimal system utilisation
• leaving choice of order implementation to mission
  planning
• orders wont expire until executed (if not
  deadlined by user)