Decision Support System for LEO Satellite Operations

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Decision Support System for LEO Satellite
Operations
by P. SomaJ.D.RaoT.V.S.R.K.PrasadP.Ekambaram
Mission Operations and Health Analysis Group
(MOHA)ISTRAC/ISROBANGALORE 560 058INDIA
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Agenda

• Objective of DSS for Satellite Operations
• How is it done?
• Sample flow chart for diagnostic
• Summary

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Objective

• The purpose of Decision Support System in
  Satellite Operations is
• To provide expert guidance to spacecraft
  controller for quick and appropriate decisions
  during real-time
• Experts need not present during routine and
  normal operations
• Multi-spacecraft operations from a single console
• Generic software adoptable for all the LEO
  satellites

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Qualities of Expert Controller

• Knowledge of Spacecraft and operational
  procedures
• Analytical approach Look for micro variations
  in the S/C performance
• Good presence of mind and quick to respond in a
  judicious way during problems and contingencies
• An excellent communicator clarity and crisp in
  communication
• Time conscious timely completion of activities
• Vigilant during realtime
• Up to date operations knowledge

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Activities of a Controller

• S/C Health Monitoring and raising critical alarms
  and parameter limit crossing
• Generation and execution of timeline sequence of
  commands
• Anomaly identification, deriving information and
  suggesting remedial actions during contingency
• Generating consolidated operations summary
  reports

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Components of DSS
Problem Processing
Knowledge
GUI
User

• GUI (communication between the user and other
  components of DSS)
• knowledge (Data/procedures)
• Problem processing (Problem manipulation for
  decision making)

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Decision Support System for IRS-P3 S/C Operations
Subsystem Rule Expert
Rule ID Generator
Rule base Generator
Procedure base Generator
CAM Table
Rule ID Table
Procedure ID
Rule IDs
CAM
CAM Triggers
Inference Engine
Suggestion Engine
Alert Engine
Display Suggestion
Display Inference
Display Alert
Anomaly Alert, Identification, Suggestion
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Decision Support System for IRS-P3 S/C Operations
Elements of Anomaly resolution Module
CAM Table
Generated by SCHEMACS Manager in consultation
with SOM/OD
Rule ID Table
Generated by Subsystem Specialist using Rule base
Expert S/W
Generated by Subsystem Specialist using Rule base
Expert S/W
Rule Base
Generated by Subsystem Specialist using Rule base
Expert S/W
Procedure base
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IRS-P3 Rule Base Table Sample Subsystem RCS
Table-1 IRS-P3 Rule Base Table
Subsystem RCS
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• List Of Anomalies For Real Time
• AOCE Processor Hang up
• AOCE-TM-2 Interface Anomaly
• AOCE Initiating Safe Mode Pulse
• Solar Panel Non-Tracking the Sun
• SPSS Threshold problem and there by Loosing SPSS
• TCP Reset
• Reaction Wheel continuously drawing high current

• Degradation study for offline
• Increase in Reaction wheel friction
• Battery cell degradation
• PB Storage not fully recording

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Decision Support System for IRS-P3 S/C Operations
Events Generator
Time line command sequence
Scheduled Events
CAM
Tracing
Suggestion
Display Events
Display Alert
Display Suggestion
Operations Supervisor
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• Operations
• Telemetry Play back and Record operations
• Sample and Continuous Record Mode selections
• payload Timer Set / Not set / Set Correctly /
  Not Set Correctly
• Expected Payload ON is not matching with
  Predicted
• TTGEN Edit commands pending/ issued
• TTGEN Pending / Issued
• TT is running / Not running
• Executed sequence is matched with the predicted
  sequence or not
• Expected commands up linked or not
• PYS/DSS offset issued or not

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IRS-P3 Spacecraft operations status and Alert
Display Sample Display
Main Window
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IRS-P3 Spacecraft operations status and Alert
Display Sample Display
DTG
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IRS-P3 Spacecraft operations status and Alert
Display Sample Display
Reaction Wheel
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System specification

• Development
• Linux and Digital UNIX work station
• C and C language
• X-Motif and QT for Graphical interface
• Final Implementation
• Digital UNIX work station
• Digital Alpha processor
• UNIX operating system
• C and C language
• X-Motif for Graphical interface

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DSS for IRS-1B anomalies

• This system will interact with the controller
  based on the inputs, compute data commands and
  On/OFF commands
• This system supports to handle
• Large yaw error correction
• Thruster momentum dumping
• Solar panel non-tracking
• Selection of conical sensor

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Large yaw error correction
N
Y
Sensor update
N
Y
Panel tracking
Sensor FOV and fold back computation
Generation of SADA commands
Power ON Gyro-1 for Yaw error polarity check
Yaw error for correction and command generation
N
Y
Gyro-1 OFF and Yaw polarity from Analog Yaw sensor
Gyro Synch
Gyro Loop close and roll rate polarity
Roll Rate
Display of Command sequence generation for yaw
control through wheels
-Yaw Error
-Roll rate
Yaw error
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Implementation Scheme for Prototype model
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Summary

• The DSS for spacecraft operations specifically
  aimed to support the spacecraft controller in any
  critical situation in multi-mission support
  environment
• DSS not to replace the S/C controller. Final
  decision to execute the recommended action is
  left to the controller
• During pass operations, the DSS is expected to
  validate the spacecraft subsystems health, as per
  defined rules and indicate to the user if the
  health is normal. The DSS also alerts the
  controller, regarding the predefined anomalies
  and suggest the possible actions to be taken
• For all inferences, the DSS should report the
  controller, reasons for arriving the conclusion

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Thank You