Avionics, Sensors, and Simulation
Project
ENAE 483 Fall 2012
Chrissy Doeren
Tom Noyes
Sean Robert
Josh Sloane
Description of Project
• Perform the avionics design for a lunar program crew cabin
• Calculate communications link budgets for the following links
o Ku band direct to Earth
o S band direct to Earth
o Ka band to L2 relay satellite
o Ku relay satellite direct to Earth
o UHF omni to EVA suits
• Compile a sensor list for all systems in the cabin
o Type and number of sensors for each signal
o Criticality of sensor
o Frequency of sampling
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Description of Project
Cont'd • Develop a list of possible Design/Build/Test/Evaluate (DBTE) projects for
ENAE 484 next term
• For each concept, briefly discuss:
o Research objective (what do we learn/why do we care?)
o Required mockup/test apparatus
o Concept of test operations (include simple sketches)
• Rank your top three concepts in priority order, based on importance and
feasibility
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Communications Link
Budget Analysis
Communications Link Budget Analysis
Link budget analysis performed using
maximum possible slant distance based on
orbital geometry
• Ku Band Direct to Earth
• S Band Direct to Earth
• Ka Band to L2 Relay Satellite
• Ku Relay Satellite Direct to Earth
• UHF Omni to EVA Suits
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Communications Link Budget Analysis
All Antennas
Overall System Architecture
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Communications Link Budget Analysis
All Antennas
Assumptions
• Ku, S, and Ka band antennas are parabolic dishes
• UHF antenna is omnidirectional dipole
• Ku and S band Earth antenna is 34 m diameter
• Deep Space Network (DSN)
• Ka band L2 relay satellite antenna is 0.3 m diameter
• UHF omni antenna is 0.11 m diameter
• Dictated by wavelength of signal
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Communications Link Budget Analysis
Slant Distances
• Ku and S bands direct to Earth: maximum
transmission distance is orbital radius of the Moon
around the Earth at apogee = 405,410 km
• Ka band to L2 relay satellite: 60,000 km
• Ku band relay satellite direct to Earth: 465,410 km
• UHF omni to EVA suits: 10 km
• Maximum EVA distance by suited astronaut
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Communications Link Budget Analysis
Ku Band Direct to Earth
Trade Studies – vary antenna size and transmit power
Transmit Antenna
Size
Receive
Antenna Size
Transmit Power Link Margin
0.3 m 34 m 0.04 W 4.01 dB
0.7 m 34 m 0.04 W 11.37 dB
0.3 m 34 m 0.12 W 8.78 dB
0.7 m 34 m 0.12 W 16.14 dB
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Communications Link Budget Analysis
S Band Direct to Earth
Trade Studies – vary antenna size and transmit power
Transmit Antenna
Size
Receive
Antenna Size
Transmit Power Link Margin
0.3 m 34 m 1 W 4.37 dB
0.7 m 34 m 1 W 11.73 dB
0.3 m 34 m 3 W 9.14 dB
0.7 m 34 m 3 W 16.5 dB
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Communications Link Budget Analysis
Ka Band to L2 Relay Satellite
Trade Studies – vary antenna size and transmit power
Transmit Antenna
Size
Receive
Antenna Size
Transmit Power Link Margin
0.3 m 0.3 m 0.5 W 3.78 dB
0.7 m 0.3 m 0.5 W 11.14 dB
0.3 m 0.3 m 1.5 W 8.55 dB
0.7 m 0.3 m 1.5 W 15.91 dB
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Communications Link Budget Analysis
Ku Band L2 Relay Satellite to Earth
Trade Studies – vary antenna size and transmit power
Transmit Antenna
Size
Receive
Antenna Size
Transmit Power Link Margin
0.3 m 34 m 0.05 W 3.78 dB
0.7 m 34 m 0.05 W 11.14 dB
0.3 m 34 m 0.15 W 8.55 dB
0.7 m 34 m 0.15 W 15.91 dB
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Communications Link Budget Analysis
UHF Omnidirectional to EVA Suits
Trade Studies – vary transmit power
Transmit Antenna
Size
Receive
Antenna Size
Transmit Power Link Margin
0.11 m 0.11 m 0.001 W 4.39 dB
0.11 m 0.11 m 0.005 W 11.38 dB
0.11 m 0.11 m 0.01 W 14.39 dB
0.11 m 0.11 m 0.05 W 21.38 dB
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Communications Link Budget Analysis
Optimum Configurations
Min acceptable link margin = 3.0 dB (2x Factor of Safety)
Link Transmit
Antenna Size
Receive
Antenna Size
Transmit
Power
Link Margin
Ku Band Direct to
Earth 0.3 m 34 m 0.04 W 4.01 dB
S Band Direct to
Earth 0.3 m 34 m 1 W 4.37 dB
Ka Band to L2
Relay Satellite 0.3 m 0.3 m 0.5 W 3.78 dB
Ku Band L2 Relay
Satellite to Earth 0.3 m 34 m 0.05 W 3.78 dB
UHF Omni to EVA
Suits 0.11 m 0.11 m 0.001 W 4.39 dB
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Sensors
Proprioceptive Sensors
• Measure internal state of system
o Position, velocity, acceleration sensors: low criticality, high sampling
rate
o Temperature, CO2, acoustic sensors: high criticality, low sampling rate
• Rotary position
• Linear position
• Velocity
• Accelerations
• Temperature
• CO2 sensor
• Acoustic sensor
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Linear and Rotary
Sensors • Rotary position [1]
o Provide an output signal that is proportional to
rotation. The sensors have a very fast start
up from power on and provide an almost
instantaneous signal
o Output calibrated to angles between 20
and 160 degrees
o Low-cost and compact
• Linear position [1]
o Provide a linear output characteristic with
displacement which can be proportional to
the supply voltage
o Compact, accurate, robust and don't need special sensitive magnetic
components or magnets which attract debris
o Used for high temperature applications, rugged, stand alone
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Velocity and
Acceleration Sensors • Velocity [2]
o Structured to accommodate the rigorous configuration control
demands of aerospace applications
o Have survived testing of: high vibration, shock, extremes of
temperature,salts, acids, solvents and fuels
• Accelerometer [3]
o Detects level of achieved
acceleration for each phase of the
mission
o -65º to 250ºF
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Temperature, CO2, and
acoustic Sensors • Temperature [5]
o Extreme temperature Hall sensor, magnetic-sensitive semiconductor
structure is built-in
o -270º to +300º C
• CO2
o Placed inside crew cabin, connected to instrumentation panel
o Low sampling rate, will trigger an alarm if levels start climbing; CO2
scrubbers may need attention
• Acoustic [4]
o Detects small meteorite impacts in earth orbit
o When a collision occurs in space, it makes a rather loud sound,
generating an acoustic wave in a wall that can be detected tens of feet
away by sensors on the walls
o Stamp-size devices, made with a very sensitive piezoelectric material
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Sensor Placement
• Collision (acoustic) sensors on bottom, where most collisions occur
• Accelerations spread out covering as much area as possible
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Avionics Architecture
Displays and Controls
Block Diagram
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Design/Build/Test/Evaluate
Concepts
• Research objectives
o Determine lines of sight for the pilot while landing the vehicle
• Required mockup/test apparatus
o Mockup of exterior of the cabin including:
Landing gear
Windows
o Interior of the cabin including
Pilot seat
Navigation display and controls
o Constructed out of
Wood and/or cardboard
Structural integrity unimportant, except for the floor of the crew
cabin
1. Line of Sight Mockup
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•
• Concept of test operation
o Pilot will perform representative operations needed during landing on
the moon
o Analyze:
Comfort of looking out of the window while operating navigation
devices
Position of avionic equipment
1. Line of Sight Mockup
(Cont'd)
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1. Line of Sight
Mockup: Sketch
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• Research objectives
o Determine appropriate locations of cameras
o Cameras needed for:
Additional visibility for landing gear
Monitor pilot's eyes/face to make sure he/she is focused
Camera with the same line of sight as the pilot, so ground support
can see what the pilot sees
Docking
• Required mockup/test apparatus
o Similar mockup from line of sight concept
o Several cameras/video cameras with different lenses (e.g. wide angle)
• Concept of test operation
o Take images at different positions
o Determine if these images provide useful information to the pilot and
ground support
2. Video Camera
Locations
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2. Video Camera
Locations: Sketch
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• Research objectives
o Construct a small scale model of our design
o Bring this mockup to grade school classrooms, as a method of
outreach
o Model should be interactive and entertaining for students
Doors should open and close
Landing gear should be able to fold in at its hinges
• Required mockup/test apparatus
o Model should be fairly rigid, possibly made out of plastic using a rapid
prototyping machine
• Concept of test operation
o A physical model will help the systems design understand what is still
needed, and how everything works together
o This model could communicate or overall design (especially to non-
engineers) more effectively
3. Small scale model of
design
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• Research objectives
o Analyze ingress and egress of the lunar lander
o Determine ladder location and spacing of the steps on the ladder to
get to the ground
• Required mockup/test apparatus
o Neutral buoyancy lab
o PVC pipe mockup of the cabin
o PVC pipe ladder
• Concept of test operation
o Diver will perform ingress and egress of the vehicle in neutral
buoyancy lab
o Diver will wear the proper amount of weights to simulate moon gravity
4. Neutral Buoyancy
Lab
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• Research objectives
o Determine feasibility of habitation of crew capsule over long durations
o Construct a full-scale, partially functioning model of our concept.
• Required mockup/test apparatus
o Mockup interior of the cabin including
Bedding
Functional food and water systems
Functional ventilation system
Functional waste disposal system
• Concept of test operation
o Three 95th percentile classmates live in the capsule for multiple
consecutive days, performing representative tasks and determining
habitability of capsule.
5. Cabin Life
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• Line of sight mockup
• Neutral buoyancy lab
• Cabin life
• All three of these concepts are feasible for the scope of our project
• These all test human factors that would be difficult to analyze with only
CAD drawings
Top 3 Concepts,
In Order of Priority
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• [1] http://www.positek.com/Overviews/p503oview.htm
• [2] http://www.smith-systems-inc.com/products
• [3] http://www.select-controls.com/acceleration.html
• [4] http://www.space.com/11856-spacecraft-sensors-sound-collisions.html
• [5] "Hall Effect Magnetic Field Sensors for High Temperatures and Harmful
Radiation Environments." Hall Effect Magnetic Field Sensors for High
Temperatures and Harmful Radiation Environments. Physorg, 22 Mar.
2012. Web. 11 Dec. 2012.
References
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