1 Arizona State University Senior Design ASU/JPL Flight System Group Members: Robert Hoffman, Dusty...

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Arizona State University Senior Design

ASU/JPL Flight System

Group Members:

Robert Hoffman, Dusty Terrill, Adam Nikolic, Josh Ruggiero

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Flight System

• Sun-Synchronous Earth Orbiting Spacecraft

• Visible and Infrared Imaging of Regions of Interest

• Software Simulation:

– Flight Dynamics

– Instrument Operations

– Command and Telemetry Processing

– Engineering Health

– Status Monitoring

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Management

Project Manager:Robert Hoffman

System Engineer Mission Control:Abe Hart

Code Manager: Filip Mladenovic

Scribe: Dusty Terrill

Testing Manager:Gary Kahler

Documentation Manger and Scribe: Steven Palmer

Tool Smith:Josh Ruggiero and Adam Nikolic

System Engineer Flight System: Robert Hoffman

Code Manager: Adam Nikolic

Testing Manager:Josh Ruggiero

Documentation Manger and Scribe: Dusty Terrill

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IEEE 1471-2000 System Architecture Design

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Communication

• Simulated TCP/IP Connection Between the Ground System and the Flight System

• Utilizing the Consultative Committee for Space Data Systems format for the data packets.

• CCSDS Header Format:

[Version][Packet ID][Second Header Flag][Type][Sequence Flags][Packet Sequence Control][Packet Data Length][Secondary Header]

Version[3]: Always 000, it’s the first versionPacket ID[1]: 0 if flight is sending, 1 if ground is sendingS.H. Flag[1]: Always 1, there is always a second header

Type[11]: Dependent on our command typeSequence Flags[2]: 00 – a continuation, 01 – first segment,

10 – last segment, 11 - un-segmented

Packet S.C.[14]: Running counter for each command typePacket D.L.[16]: Number of bytes in the array – 1Sec Header[32]: Contains the timestamp

• The header will therefore always contain 80 bits worth of data and the following bits will be the data that needs to be sent.

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Prototype Class Diagram

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Subsystems

• Power

• Command and Data Handling

• Telecommunication

• Mechanical

• Thermal

• Propulsion

• Guidance Navigation and Control

• Payload

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Power Subsystem & Peripherals

• Solar Array

• Battery

• Power Control

• Power Switching

• Power Conversion

• Cabling

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Command and Data Handling Subsystem & Peripherals

• Memory

• Command

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Telecommunication Subsystem & Peripherals

• Directional Antenna

• Wide Beam Antenna

• Transmitter

• Receiver

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Thermal Subsystem & Peripherals

• Thermal Sensors

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Propulsion Subsystem & Peripherals

• Thrusters

• Reaction Wheels

• Fuel Tank

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Guidance Navigation and Control Subsystem & Peripherals

• Star Tracker

• Sun Sensor

• Propulsion Control Subsystem

• Actuator Control

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Payload Subsystem & Peripherals

• Camera

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Commanding Information

• CCSDS Timestamp Included

• Use to sort commands by time

• Use to acknowledge command received / executed

• Every command flight receives must be acknowledged

• Sequence of commands to run

• Must know the sequence

• Must be able to save sequence to run at a later time

• Format of Commands

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Command Formatting

• Commands received by flight

– [7 bit command #] [ 64 bit start time] [ extra command data]

• Commands sent by flight

– [7 bit command #] [ 32 bit received time] [ extra command data]

• Ensures compatibility among all commands

• Each commands part of subgroup

– Easy to manage commands by type

– Easy to add commands later if needed

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Flight Received Commands• Propulsion• 0) [Fuel Tank Command] [Start Time(ms)] [0] – 0- send fuel remaining

[0000000] [64 bit long] [0][Fuel Tank Command] [Start Time(ms)] [1] - 1- stir tank[0000000] [64 bit long] [1]

• 1) [Fire Thruster Command][Start Time(ms)][Thruster #][Runtime(ms)][0000001] [64bit long] [XXXX] [32bit int]

• Camera• 10) [Camera Command] [Start Time(ms)] [Sub Command] [DATA]

• Sub Commands – Power 00Calibrate 01

• Picture 10

– [Camera Command] [Start Time(ms)] [Power Command] [On/Off/Rst]

– [0001010][64 bit long][00][XX] – 00 Turn Off; 01 Turn On; 10 Reset

– [Camera Command] [Start Time(ms)] [Calibrate command]

– [0001010][64 bit long][01] - Calibrate

– [Camera Command] [Start Time(ms)] [Picture Command] [IR/Reg] [Filter] [aperature] [shutter speed]

– [0001010][64 bit long][10][X][XXX][32 bit float][32 bit int] - Take Picture

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Flight Sent Commands

• Propulsion• 00) [Tank Sensor Command][Time(sec)][0][Fuel Left]

– [0000000][32 bit int][0][32bit Float] [Tank Sensor Command][Time(sec)][1] – ACK Stir Tanks [0000000][32 bit int][1]

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• 01) [Thruster Command][Time(sec)][Thruster #][0] – Command Received[0000001][32 bit int][XXXX][0]

• [Thruster Command][Start Time(sec)][Thruster #][1] – Command Executed

• [0000001][32 bit int][XXXX][1]

• Camera• 10) [Camera Command][Time(sec)][Power Command][On/Off/Rst] – Power Ack

• [0001010][32 bit int][00][XX] – 00 Turn Off; 01 Turn On; 10 Reset

• [0001010][32 bit int][01] – Calibrate Ack

• [Camera Command][Time(sec)][Picture Command][Picture Size(bits)][Picture]

• [0001010][32 bit int][10][32 bit int][Picture Data (.jpg)]

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Internal Commands

• Sample flow chart

• Must simulate all aspects of internal communication

• Each command is internally represented and handled specifically

• All internal communications must go across the system bus

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Internal Command Examples

• Fuel Tank[0]: Send Fuel Remaining

• Internal command # 1

• System bus events: Propulsion.getFuel()

• Create new packet (Fuel)

• Telecom.send(packet)

• Fuel Tank[1]: Stir Fuel Tank

• Internal command # 2

• System bus events: Propulsion.sitrTank()

• Create new packet()

• Telecom.send(packet)

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Command Run-Through Example

• Flight receives command from ground

– 0) [Fuel Tank Command] [Start Time(ms)] [0] – 0-send fuel remaining[0000000] [64 bit long] [0]

• Command parse / execute

• Send information to system bus

– Fuel Tank[0]: Send Fuel Remaining

Internal command # 1

System bus events: Propulsion.getFuel()

Create new packet (Fuel)

Telecom.send(packet)

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Command Run-Through Example Cont…

• Packet created stores all information

[Tank Sensor Command] [Time(sec)] [0] [Fuel Left]

[0000000][32 bit int] [0] [32bit Float]

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What Worked

• Plenty of Brainstorming• Working with two groups had more ideas

• First semester is all planning phase• Regular Meetings• Proper collaboration with Ground Team• Working with JPL Advisor

• Good direction

• Good plan of action and organization

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What Didn’t Work

• Schedule Slippage towards beginning• Abundant amount of proper research• Redoing reports and paperwork

• Originally, not enough information

• Losing UML class diagrams• Very difficult command creation

• Original set not to standards• Complete Architecture Reorganization

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Schedule

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Questions?

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