• Share
  • Email
  • Embed
  • Like
  • Save
  • Private Content
MEMS - based Inertial Navigation Systems onboard Balloons
 

MEMS - based Inertial Navigation Systems onboard Balloons

on

  • 1,610 views

 

Statistics

Views

Total Views
1,610
Views on SlideShare
1,605
Embed Views
5

Actions

Likes
0
Downloads
35
Comments
0

1 Embed 5

http://www.slideshare.net 5

Accessibility

Categories

Upload Details

Uploaded via as Microsoft PowerPoint

Usage Rights

© All Rights Reserved

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Processing…
Post Comment
Edit your comment

    MEMS - based Inertial Navigation Systems onboard Balloons MEMS - based Inertial Navigation Systems onboard Balloons Presentation Transcript

    • MEMS - based Inertial Navigation Systems onboard Balloons Giovanni B. Palmerini - Emanuele Medaglia Maria Cristina Oliva - Paolo Montefusco 1st Workshop on Science and Technology through Long Duration Balloons, INAF-Rome, June 3-4, 2008
      • Rexus - Bexus is a bilateral German-Swedish cooperation to offer students experiment opportunities using sounding rocket and stratospheric balloon flights from Esrange in Northern Sweden.
      • Each flight will carry a payload consisting solely of student experiment.
      • An announcement of opportunity was made in November 2007 for flight campaigns in 2008 and 2009.
      • - Esrange Space Center is located in northern Sweden, 45 km from the town of Kiruna at 67 o N, 21 o E
      • - Esrange has been the site of many campaigns, involving different types of balloons (more than 500 launches)
    • BEXUS experiments are lifted to an altitude of 20-35 km for a flight duration of 2-5 hours, depending on total experiment mass (40-100 kg). The balloon has a volume of 12000 m 3 , and an inflated diameter of 14m
      • Flight duration : 2-5 hours
      • Altitude : 25-35 Km
      • Acceleration : -10g vertically and ±5g horizontally
      • Landing velocity : 8 m/s (approx.)
      • Thermal environment : down to -90 °C
    • Our entry for BEXUS payload selection is LOWCOINS, for LOW COst Inertial Navigation System , an experiment based on the recently available MEMS (Micro Electro Mechanical Systems) technology The advantages of MEMS sensors: – Lightweight – Volume and Power minimal requirements – Low cost – Availability – Ruggedness – Reliability Gyros Accelerometers Resolution of measurements Double integration G-loop Attitude determination
      • State:
      • Position
      • Velocity
      • To learn
      • To investigate the feasibility of a MEMS-based INS in a slow dynamic environment
      • To estimate errors derived by using COTS components
      • To compare results with more precise navigation system (GPS) provided by Bexus (EBASS bay)
      • To provide attitude data for the gondola
      • To verify the possibility to offer an inexpensive backup in case of main system unavailability
      • LOWCOINS experiment is an INS based on a strapdown design
      • Inertial measurements are gained by MEMS-based motion sensing devices
      • A Microchip PIC processor will collect measurements, compute an approximate solution, provide data to balloon housekeeping for downlinking to ground and store data into a flash memory
      • Different sensors (pressure, magnetic) will be added to improve the inertial solution
    • Magnetic Field Sensor Pressure Sensor Attitude Determination Measurements Reduction Navigation Computer Double integration Position & Velocity Temperature Sensor Gyros Accelerometers
    • Magnetic Field Sensor Pressure Sensor Attitude Determination Measurements Reduction Navigation Computer Double integration Position & Velocity Temperature Sensor Gyros Accelerometers
    • Gyros Accelerometers Magnetic Field Sensor Pressure Sensor Attitude Determination Measurements Reduction Navigation Computer Double integration Position & Velocity Temperature Sensor
      • Comparison between on-board data (computed with limited resources, i.e. at a limited data rate) and exhaustive on ground processing (complete data set + calibration for on-the-run drift)
      • Test of the solution validity with re-alignment (from “official” data performed at various times and mission phases)
      • Behavior of the error equation for the INS obtained considering the “official” telemetry data – GPS benchmark - as the true solution and linearizing about (i.e. check the performances of MEMS sensors on different time-scales)
      • Acquisition of hands-on experience on sensors’ errors and calibration
      • Analog Devices
      • ADIS16355
      • High precision three-axes inertial sensor
      • ± 10 g , ± 300 °/s range
      • 14 bit resolution
      • Factory calibrated sensitivity, bias and alignement
      • -40 °C to +85 °C
      • SPI compatible serial interface
      • Speake & Co Llanfapley
      • FGM-2 FGM-1
      • High sensitivity 2-axis and 1-axis magnetic field sensors
      • +5 volt operations
      • The output is a robust 5 volt rectangular pulse whose period is directly proportional to the field strength
      • Honeywell
      • ASDX015A24R
      • Pressure ranges from 0 to 15 psi
      • 5.0 Vdc supply
      • High level output (4.0 Vdc span)
      • Quantization step of 3 mV
      • Wide compensated temperature range 0 °C to 85 °C
      • Microcontroller specification:
      • Microchip PIC 18F2620
        • 28 pin microcontroller
        • Up to 40 MHz clock
        • SPI & I 2 C interface
        • 10 channel 10 bit ADC
        • 64 Kb program flash memory
      • Flash memory specification:
      • ATMEL AT45DB161D
        • 8 pin SOIC serial flash memory
        • 16 Mbit
        • 3 wires SPI interface
    • To PC (Service Mode) E-LINK TM/TC interface Voltage Regulator SPI bus 3.3 V & 5 V To components HEATER ANALOG DEVICES ADIS16355 IMU FGM-2 FGM-1 Magnetic Field Sensors PIC microcontroller RS 232 interface Pressure Sensor battery pack Flash Memory 1 Flash Memory 2 Flash Memory 3 Flash Memory 4 Temperature Sensor
      • 64 Mbit memory allows for up to 6.4 hours of data recording
      Measurement Resolution (bit) Memory occupation (bytes per sample) Sampling Frequency (Hz) 3 accelerations 14 2 20 3 angular rates 14 2 20 3 magnetic field components 16 2 20 1 temperature 12 2 1 1 pressure 10 2 1 TOTAL 364 bytes/s 2912 bps
    • G. Palmerini, E.Medaglia, P.Montefusco, M.C.Oliva “ MEMS-based Inertial Navigation Systems onboard Balloons” 1st Workshop on Science and Technology through Long Duration Balloons, Rome, June 3-4, 2008 LOWCOINS board - sensor part layout April 2008
    • G. Palmerini, E.Medaglia, P.Montefusco, M.C.Oliva “ MEMS-based Inertial Navigation Systems onboard Balloons” 1st Workshop on Science and Technology through Long Duration Balloons, Rome, June 3-4, 2008 LOWCOINS board Power and heating portion layout May 2008
    •  
    • Past BEXUS flights indicate possible problems for COTS components The combination of undetermined temperature range and flight duration led to consider conservative solutions
      • Requirement: Electronics should be kept above ~ 0 °C
      • Step 1 - Theory
      • Hypotheses
        • Worst case external temperature: -90 °C
        • Isothermal conditions inside the box
        • Heat transfer by conduction through housing walls
        • Insulation panels: foam 3 cm thickness with k=0.03 Wm -2 K -1
      • Findings
        • 10 W are required to keep a temperature difference of ~ 100 °C
      • Experiment insulation box:
        • 20x20x15 cm
      • Foam panels with aluminium skins:
        • 3 cm thickness
        • 30 Kg/m 3 density
      The microprocessor switches the heater on whenever the temperature T0 (middle of the component side) falls below 15°C and turns it off above 20°C.
    • Test conduced in presence of free convection! Test in thermal-vacuum chamber needed to define thermal control power requirements
      • Even with a really conservative contingency the power requested by sensors and data processing is limited
      • Thermal conditioning will be the driver
        (mA) @ 5V Analog Devices ADIS16355 57 Pressure sensor - ASDX015A24R 6 Magnetometers - FGM 1 + FGM 2 24 PIC 18F2620 2 ATMEL AT45DB161D 12 ICL 232 10 Contingency 50 TOTAL 150
      • 10 W for thermal control
        • 1.5 W experiment self heat
        • 8.5 heater
      • 3 LSH20 battery (10.8 V)
        • @ 1 A discharge current
        • Effective capacity: 7 Ah
        • Allows for 7 hours of operation (heater always on!)
        • Reliable (ESA suggested part)
    •   Mass (grams) Analog Devices ADIS16355 16 Pressure sensor - ASDX015A24R 2 Magnetometers - FGM 1 + FGM 2 5 PIC 18F2620 6 ATMEL AT45DB161D 1 LSH 20 battery pack (3 cell) 300 Housing (aluminium) 2000 (20x20x15 cm - 0.2 cm thickness) Contingency 200 TOTAL 2500
      • Constrained by the uncertainties on the actual take-off time and on the flight duration:
      • Experiment powers up plugging a connector with shorted pins which acts as an outside-located switch
      • The unit goes in sleep mode during launch preparation phase
      • The unit wakes up and starts recording upon telecommand reception
      • The unit goes in sleep mode when memory is full
      • Northrop Grumman Italia (NGI) kindly agreed to support LOWCOINS activities, providing help in different fields
      • The company, in a cooperation scheme which allowed for the students to have their stage at NGI, granted:
        • Support for mechanical and thermal interface design and manufacture
        • Advice for electrical & software design
        • Facilities for experiment hardware building & testing
          • Soldering for SMT components
          • Thermal chamber
          • Vacuum & thermal-vacuum chamber
          • Vibe tests
          • Static calibration
          • Dynamic test campaign
      • Paolo :
        • Electronic design
        • Onboard software development
        • Power Interface
        • Mechanical interface
        • Post-processing software for attitude and position determination
      • Maria Cristina :
        • Ground station software developer for TM/TC handling
        • Real-time computation
        • Mechanical design
        • CAD design
        • Webmaster
        • Post-processing software for attitude and position determination
      • Emanuele :
        • Thermal interface
        • Thermal and Structural analysis
        • Onboard computation
        • Post-processing software for attitude and position determination
      • 16 Nov 2007 - Announcement of opportunity for BEXUS 7 experiments
      • 7 Jan 2008 - Deadline for applications
      • 28 Jan 2008 - Announcement of short-listed proposals and invitations to workshop
      • 5-6 Mar 2008 - Workshop at ESA-ESTEC in Noordwijk, The Netherlands
      • 15 Mar 2008 - Announcement of final selection of the experiments for BEXUS 6 & 7 flight
      • 21-25 Apr 2008 - Student Training Week and Preliminary Design Review (PDR) at Esrange in Kiruna, Sweden
      • 20 June 2008 - Critical Design Review (CDR)
      • end Aug 2008 - Delivery of experiments to Esrange for Experiment Acceptance Review (EAR)
      • tbd Oct 2008 - BEXUS 7 Launch Campaign at Esrange
      • 15 Jan 2009 - Submission of Experiment Reports to ESA