fluxgate magnetometer (fgm) kathryn rowe...fluxgate magnetometer ‐ 3 axis data stream ‐ 24 bit,...
TRANSCRIPT
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FGM-1 MPDR, 2/12/2015
FLUXGATE MAGNETOMETER
Fluxgate Magnetometer (FGM)
Kathryn Rowe
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FGM-2 MPDR, 2/12/2015
TEAM ORGANIZATION
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FGM-3 MPDR, 2/12/2015
Instrument Overview Instrument Description Development Overview
AGENDA
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FGM-4 MPDR, 2/12/2015
INSTRUMENT OVERVIEW
4
ELFINFluxgate Magnetometer (FGM)Mission PDR Meeting
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FGM-5 MPDR, 2/12/2015
EXPLODED VIEW
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FGM-6 MPDR, 2/12/2015
Magnetic sectoring information for the EPD Potential to detect EMIC waves
WHY DOES ELFIN NEED AMAGNETOMETER?
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FGM-7 MPDR, 2/12/2015
1. FGM Electronics
2. FGM Sensor/Cable
WHAT DOES THE FGM CONSISTOF?
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FGM-8 MPDR, 2/12/2015
BLOCK DIAGRAM
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FGM-9 MPDR, 2/12/2015
RFAS FROM PDR
1
FGM Resolution Requirement -- Waiting Board ApprovalThe FGM Resolution of 10pT was presented as a requirement whereas the noise level is 0.5nT/sqrt(Hz). The PRM may generate data with
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FGM-10 MPDR, 2/12/2015
INSTRUMENT DESCRIPTION
ELFINFluxgate Magnetometer (FGM)Mission PDR Meeting
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FGM-11 MPDR, 2/12/2015
Fluxgate Magnetometer‐ 3 Axis data stream‐ 24 bit, 6pT resolution‐ Dynamic Range: ±55,000nT‐ Noise: 0.4nT/√Hz @ 1Hz‐ Sample rate: 200Hz
Instrument DescriptionMagnetometer Electronics
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FGM-12 MPDR, 2/12/2015
POWER REQUIREMENT - FGM
REQ ID Requirement Parent(s) Verification Method Verification Procedure
PLD‐35
The Payload subsystem shall not exceed the power allocated in the ELFIN system power budget
SYS‐22
T/A: Measured power consumption data during component tests; Analysis of the complete set of Instrument states.
Power BudgetPowerBudget‐##‐B.xlsx
Power allocated for FGM: 0.5 W (during science data collection)Current best estimate: 0.423 WMargin: 15 % (0.063 W)CBE + Margin: 0.486 WContingency: ~0.014 W
Supply voltages: Currents:+8 V+3.3 V+1.5 V
30 mA35 mA45 mA
Power:0.24 W0.1155 W0.0675 W
0.423 W+
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FGM-13 MPDR, 2/12/2015
PWA mounts to 4 Delrin® brackets with 2-56 socket head brass bolts at each corner
ELECTRONICSMECHANICAL INTERFACE
The Delrin® brackets connect to cubesat chassis with #4-40 countersunk brass screws, and the PWA lies perpendicular to the instrument stack
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FGM-14 MPDR, 2/12/2015
INSTRUMENT DESCRIPTIONMAGNETOMETER SENSOR
3 Axis Fluxgate 48mm x 48mm x 25mm 58 grams without cable 106 grams with 1 m cable
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FGM-15 MPDR, 2/12/2015
1. Conductor – 3 Twisted Pairs Material: Silver-Coated
Strength Alloy Thickness of Silver Coating:
2um min Size: AWG 28
2. Binder Material: Gore-Tex®
3. Severed Wire Shield Material: Solver-Coated,
oxygen free Cu Thickness of silver coating:
2.5um min4. Shcatch
Material: Gore-Tex®
FGM CABLE
Characteristics:Operating Voltage: 100VrmsOperating Temp Range: -150C to 200C
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FGM-16 MPDR, 2/12/2015
Stacer is 75cm long Sensor connects to
stacer with #4-40 non-magnetic screws
Final harness length TBD. CBE is 100cm
MLI installed over sensor
SENSOR MECHANICAL INTERFACE
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FGM-17 MPDR, 2/12/2015
STACER Keleva Design Inc A 75cm BeCu stacer boom with a
SMAR actuator and a flywheel break
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FGM-18 MPDR, 2/12/2015
MASS REQUIREMENT - FGMREQ ID Requirement Parent(s) Verification Verification Document
PLD‐34 The Payload subsystem shall not exceed the mass allocated by Systems SYS‐14
System mass documented and tracked through assembly, integration and test
Mass BudgetMassBudget‐##‐E.xlsx
Mass allocated for FGM: 237 gCurrent best estimate (CBE): 199 gMargin: 15 % (29.9 g)CBE + Margin: 228.9 gContingency: 8.1 g
FGMComponent Maturity Qty Unit mass CBE Margin CBE+Margin
FGE (FGM Electronics) P 1 90.00 90.0 15% 103.5FGS (FGM Sensor with 1m cable) P 1 109.00 109.0 15% 125.4
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FGM-19 MPDR, 2/12/2015
DEVELOPMENT OVERVIEW
ELFINFluxgate Magnetometer (FGM)PDR Meeting
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FGM-20 MPDR, 2/12/2015
FGM REQUIREMENTS
REQ ID Requirement Parent(s) Comply?
FGM
PLD‐21 The FGM shall have a range of 55,000 nT SCI‐01, SCI‐04, SCI‐05Yes. Current dynamic range is ±58,400nT
PLD‐22 The FGM shall have a resolution of 0.1nT SCI‐01, SCI‐04, SCI‐05 Yes. Current resolution is 7pT.
PLD‐23 The FGM shall have an absolute stability of 100 nT SCI‐01, SCI‐04, SCI‐05 Need to test
PLD‐24 The FGM shall have a relative stability of 1 nT/2 hr SCI‐01, SCI‐04, SCI‐05 Need to test
PLD‐25 The FGM shall have a noise level of 0.5 nT/sqrt(Hz) SCI‐01, SCI‐04, SCI‐05Yes. Current resolution is 0.4nT/sqrt(Hz)
PLD‐27 The FGM shall have a digitization of > 20 bits SCI‐01, SCI‐04, SCI‐05Yes. Current digitization is 24 bits
PLD‐28 The orthogonality of the FGM sensor shall be known to
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FGM-21 MPDR, 2/12/2015
Prototype Complete (Board and Sensor)
CURRENT STATUS OF INSTRUMENT
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FGM-22 MPDR, 2/12/2015
Elfin Status (2/26/12) PRM with ST5 Sensor Feedback Resistor: 2.7K to 3.3K
Problems: Frequency Response Incorrect: LabView needs to be
updated Need New Drive Circuit
X axis Offset: 1867nT Dynamic Range: +/-64,000nT Noise Level: 402pT at 1Hz
Y axis Offset: -49nT Dynamic Range: +/-64,000nT Noise Level: 379nT at 1Hz
Z axis Offset: 3129nT Dynamic Range: +/-58,400nT Noise Level: 373pT at 1Hz
Power Consumption 3.3V: 32mA 1.5V: 42mA 8V: 28mA
TEST DATA
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FGM-23 MPDR, 2/12/2015
STABILITY TESTING(2 HOURS)
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FGM-24 MPDR, 2/12/2015
FGM IMPLEMENTATION PLAN
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FGM-25 MPDR, 2/12/2015
1. Reduce dynamic range on X and Y axis From ±64,000nT to ±55,000nT Feedback resistors needs to be changed Increases margin on noise level
HARDWARE CHANGES NEEDED ONPROTO
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FGM-26 MPDR, 2/12/2015
1. Change input clock from 32MHz to 16.384MHz GSE oscillator needs change
2. Change sample rate from 122Hz to 200Hz Need to implement anti-aliasing filter IDPU to average down to 10Hz
3. Change FPGA code from Libero Schematics to Verilog
FPGA CHANGES NEEDED ONPROTO
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FGM-27 MPDR, 2/12/2015
1. Electronics Thermal Cycling (Expected temperature range needed) Need test plan Need to determine electronics temperature
dependence2. Sensor Temperature Cycling (Expected
temperature range needed) Need test plan Need to determine sensor temperature
dependence3. Alignment Test Need orthogonality of sensor
PROTOTYPE TESTING
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FGM-28 MPDR, 2/12/2015
1. Minor board outline change Need to accommodate S/C harnessing
2. Remove JTAG connections on IDPU connector Lose ability to program in-flight (low risk)
3. Change connector from 26pin to 20pin Smaller connector to increase board space
4. Add ±15V supplies to IDPU connector WCA revealed supply rails for analog switch was
undervoltage5. Bring the drive circuit outside PRM Unable to change supply rails for analog switch
inside PRM
CHANGES FROM PROTO → EM