AubieSatI

1
AubieSat-I

• Final Review
• April 23 2008

2
Spring 2008 Goals

• Build and test a table-top version of AubieSat-I
• Build components of all sub-systems and test them
• Build and test individual sub-systems
• Integrate and test full system
• Finish building ground station and be able to
  receive satellite signals

3
System Engineering
4
System Engineering
5v
PLYD
EPS
CDH
5v,3.3v,3.7v, Data lines
CNTRL Data Lines
COMM
5v
GND Station
5
Systems Engineering

• Accomplishments
• ICD and other interface documents created and
  updated
• Pin-out diagram completed.
• Main board template done.
• Interfacing between systems started
• Testing procedure for AS-1 system done.

6
Systems Engineering

• 80 individual lines available.
• 43 individual lines needed.
• Extra pins will be used to double up higher
  current lines and replicate the data lines.

40 Pin Header
Control Lines
Control Lines
GND
GND
3.3V
5v
3.7v
USART
SPI
I2C
40 Pin Header
7
40 Pin Headers (ORCAD)
8
Standard PCB
9
Payload

• End of Semester Status Report

10
Payload

• Goals
• Camera Module
• High Speed Data Line
• Multiple I2C interface
• External Memory
• Magnetometer
• Fight Song
• Self Power Regulation
• Science Mission

11
Payload

• A Bayer filter mosaic is a color filter array
• By integrating this array we can create pixels.
• The array Pattern is
• 2 Green cells per pixel
• 1 Blue cells per pixel
• 1 Red cells per pixel

12
Payload
13
Payload
14
Payload

• Magnetometer
• Honeywell HMC1052L
• 2 axis Magnetometer
• Sensitivity
• 160 micro-gauss increments
• Output
• Analog Voltage signal
• (Vdd, 0)

15
Payload

• Power Control Modules

CDH
VDD
Payloads Main Microcontroller
Secondary Receiver
Power Line Control Line
Cameras
EXT CLOCK
Memory
16
Payload

• Completed
• Magnetometer
• High Speed Clock Line
• Dual I2C Lines
• 1x Master
• 1x Slave
• External Memory
• Fight Song (for Demo)
• Emergency Shutdown
• Subsystems individual power control.

• Summer Goals
• Finish Image Processing
• Interface high speed Bus
• Media Formats
• Collect images on demand
• Integrate into one system
• System Level Testing

17
CDH
Jaeho Jeon Mac Champion William Fiser Nathan
Shafer Hung Nguyen Aaron Scott Gurjot Singh
18
CDH Block Diagram
19
Accomplishments this Semester

• Successfully got uC/OSII Real-time Operating
  System running on the microcontroller with
  task-based execution
• Successfully implemented the following
  interfaces I2C, SPI, and serial interface
• Successfully read and write to flash memory over
  SPI, read data from ADCs over I2C, and triggered
  the antenna switch relay.
• Successfully implemented AX.25 protocol.

20
Software Results

• Wrote software to
• Read from multiple ADCs (Analog to Digital
  Converters) over I2C (Inter-Integrated Circuit)
  Interface
• Switch antenna relays
• Read and write data into flash memory via SPI
  (Serial Peripheral Interface)
• Send and receive data packets using AX.25
  protocol.

21
Future Goals

• C DH needs to continue hardware integration
  with other subsystems
• We also need to write a consolidated
  demonstration program using all available
  communication protocols, demonstrating all
  individually completed functions

22
EPS

• Brad Dutton
• Stephan Henning
• Grant Moore
• George Starr

23
EPS
Satellite
HSS
Solar
Charger
Cells
Battery
RBF
Deploy
24
EPS
MAX8677c Charger IC

• Allows for internal source switching
• Automatic transition between S.C. and Batt.
• Batt. not used unless system load is larger then
  what the S.C. can supply.
• Batt. used when needed, otherwise kept fully
  charged.

• Ground support charge port
• Isolated from rest of system
• Doesnt need to be a part of the Kill/RBF switch
  circuit.
• 2.5W available to the satellite in this state.

25
EPS
MAX1705, MAX1709, LTC3533

• Redundant regulators provide insurance
• Provide two basic functions
• Overall redundancy
• Additional power transfer
• Regulators are not pushed as hard as both
  regulators supply the same load in normal
  conditions. Diodes provide source isolation and
  protection against shorted failures.

• LTC3533
• Stabilizes SC output
• Provides clean power to the MAX8677c
• MAX8677c requires 3.9vltinputlt6.5v
• Solar Cell output will vary over period of SC
  rotation.

26
Power Budget Summary
27
SC array PSPICE model
28
(No Transcript)
29
EPS

• Accomplishments
• 3.3v regulators working
• Output measured under load, compared to no load
• Switching frequencies on par with expected
  results
• Chargers working
• Source switching/load assist works as expected
• Thermal stuff down works
• Parallel charging works

• Problems
• 5v regulators
• Cannot handle loads over 500mA
• Switching frequency of output measured.
• Found to be exceeding the 680kHz rating under no
  load conditions
• Causal analysis not completed.

30
EPS
To Be Done

• Troubleshoot 5v regs
• Prototype SC regulators
• Integrate RBF/Deployment switches
• Long term test to verify system operation.

31
Communications Subsystem(Primary Team)

• Jeremy Echols
• Josh Jacobs
• Josh Martin
• Beth White

32
Block Diagram of CommunicationsPrimary Subsystem
33
Accomplishments

• Establish communication between the VX-2R and
  ground station
• Build and test the antenna switching matrix
• Build and test power relay for the VX-2R
• Build and test a table top prototype of the
  subsystem
• Integrate with other subsystems
• Integration process has begun

34
Communication with Ground Station

• Able to successfully communicate with ground
  station
• Replaced old software to communicate using AX-25
  format
• Now using AGW Packet Engine

35
Antenna Switching Matrix
Primary Transceiver
HF3 93 Relay
Secondary Receiver
HF3 93 Relay
36
Antenna Switching Matrix - Design

• Axicom HF3 93 Relays
• 3ms pulse of at least 3.75Vdc to switch relay
• 50 ohm impedance
• Low cost

37
Antenna Switching Matrix - Design

• Microstrip transmission lines
• RT/duroid 5870 one-sided high frequency laminate
• Thickness 31 mils
• Dielectric constant 2.33
• Must achieve 50 ohm characteristic impedance
• Width of transmission lines 2.34mm
• Pins of relays connected to transmission lines
  with wires
• Will this cause reflections?
• No! The wires are fractional wavelength (_at_
  450MHz, wavelength0.667m.)

38
Antenna Switching Matrix - Design
39
Antenna Switching Matrix -Testing

• Do lines have a 50 ohm characteristic impedance?
• Does the matrix switch between the two antennas?
• Does the matrix sufficiently attenuate the
  signals?

40
Power Relay

• Controlled by both CDH and secondary COMM
• An interface to turn the VX-2R on and off when
  necessary
• Components
• J-K Flip Flop
• NAND gate
• Inverter
• HEXFET Power MOSFET

41
Power Relay Schematic
42
Power Relay Details

• A clock pulse from CDH or removal of 5V signal
  from secondary COMM will shut off the VX-2R
• Another clock pulse or 5V signal applied again
  will turn it back on
• 5V signal applied to the gate of the MOSFET
  effectively opens and closes a switch to control
  the power to VX-2R

43
Future Work to be Completed

• Build new versions of the following components to
  fly on the satellite
• Antenna switching matrix
• Power relay
• Complete integration with necessary subsystems
• Determine the best layout for all components to
  successfully fit in the satellite

44
Communication TeamSecondary Receiver

• Andrew Wood
• Amanda Bowman
• Kris Peebles
• James Curtis

45
Overview
46
Progress this Semester

• Prototype
• Table-top version
• Integration
• Ground Station
• Primary Comm.
• PCB board layout.

47
Prototype Hardware

• Receiver
• Chip
• Melexis TH71102
• Development Board
• Melexis EVB71102
• Decoder
• Holtek HT12D

48
Test Results
Input (Switches)
Output (LEDs)
49
Integration Results

• Ground Station
• Able to receive and decode commands wirelessly at
  short distances
• Able to display received commands using (LEDs)
• Primary Comm.
• Able to shut down primary receiver to meet FCC
  requirements

50
Software Results

• No software involved!

51
Future Work

• Print board layout
• Create Gerber and drill file
• Solder parts onto board
• Verify correct routing and placement

52
Mechanical Systems

• Kevin Carpenter
• Kris Peebles
• Andrew Long
• Scott James

53
Progress

• Changes in external structure
• Solar cell orientation
• Solar cell depression
• RBF pin / comm. port

54
Progress

• Changes in internal structure
• Custom board spacing / pin headers
• Battery / magnet mounting
• Top plate mass reduction

55
Hardware

• Structure
• Aluminum 7076
• 6 external pieces
• 24 spacers
• 2 battery / 2 magnet mounts
• Fasteners
• 4 10-24 100mm long bolts
• 16 - 6-32 machine screws

56
Hardware

• Antenna Deployment
• Antenna
• Nitinol Wire
• Hinge
• Heating Element
• Nichrome Wire
• Fishing line
• Guides
• Spring

57
Hardware

• Miscellaneous Parts
• Deployment Switches
• Deployment Springs
• Pin Headers
• Isolation Spring

58
Results

• Space requirements (z-axis)

59
Results

• Thermal Modeling
• Internal
• Conduction
• Radiation
• External
• Radiation

60
Results

• Improvements
• Contact Resistance
• Shape Factor
• Problem Areas
• Transceiver
• 5W
• Low efficiency
• TNC-X
• 2.5W

61
Results

• External
• Highly dependent on rotation
• Radiation Sources
• Sun
• Albedo

62
Future Work

• Changes to structure
• Deployment switches
• Bolt / spacer selection
• Add hystersis material
• Test pin headers
• Change PCB dimensions
• Add isolation spring

• Improve thermal analysis
• Begin vibration analysis
• Build 2nd structural prototype
• Thermal / Vibration Testing

63
Ground Station

• Byron Caudle
• Eric Grimes
• David Speck

64
Ground Station
65
(No Transcript)
66
Secondary Command Control

• Theory of operation
• Four parallel data bits representing a given
  command are serialized and output via a PWM
  signal.
• The PWM signal feeds the FM modulation port on an
  FM generator, resulting in an FSK signal.
• The FSK signal is amplified and transmitted to
  AS-1.
• Components
• Encoder operational
• Verification of encoder through decoder
  operational
• Control Box assembled and operational
• FSK-RF generator assembled and operational
• High-power RF amplifier to be determine at a
  later date.

67
Secondary Comm FSK system
68
Other Ground Station Items

• Receiver pre-amplifier purchased and installed.
• New GS computer assembled and operational.
• GS room arrangement cleanup and organization
  largely completed.
• Television mounted and operational.

69
Ground Station Software

• Goals to April 23
• Develop software to demonstrate data-displaying
  and command-sending capabilities.
• Adapt programs to actual data formats
• Document all accomplishments and comment all
  programs.
• Accomplishments
• Graphical User Interface constructed that allows
  user to send commands and display data for
  demonstration purposes.

70
xlssetup.m
SelectionChangeFcn
InitializeSpreadsheet
totext.m
datadisplay.m
DetermineCommandCode
DetermineCommandNumber
Read Datafrom Text File
Write Codeto Text File
Write Value to NextColumn
Determine Proper Value
Write Value to LatestColumn
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Any Questions?