1
Project BLISS
Boundary Layer In-Situ Sensing System
Customer
Dr. Suzanna Diener
Northrop Grumman
Faculty Advisor
Dr. Donna Gerren
Team
Kyle Corkey
Devan Corona
Grant Davis
Nathaniel Keyek-Franssen
Robert Lacy
John Schenderlein
Rowan Sloss
Dalton Smith
2
Outline
• Project Overview
• Major Changes and Status Update
• Test Readiness
▫ Delivery System
▫ Measurement System
▫ Cloud Observation System
• Budget Update
3
Project Deliverables
• 3-Dimensional U-, V-, Winertial wind vector data inside
the measurement cylinder
• Cloud base altitude and cloud
footprint data above the
measurement cylinder
Measurement Cylinder
4
Levels of Success
Delivery System
Level 3:
Execute flight plan
following points spaced
no more than 30 meters
apart spanning the
defined airspace in the
15 minute time limit with
Measurement System
onboard and collecting
data
Measurement System Cloud Observation System
Level 3:
Deliver U-, V-, W- inertial
wind velocity vector field
with temporal and spatial
location for each
measurement accurate
to 1 m/s with a
resolution of 0.1 m/s.
Level 3:
Deliver time-stamped cloud
footprint images and cloud
base altitude measurements
at 1/4 Hz during the 15
minute test period.
5
Concept of Operations
Legend
Airspace Test
Volume Subject
To Modeling
Within
Project
Scope
In-Situ Relative Wind
Velocity Data
Collection and Cloud
Imaging
NG model
wind vector
100 m
200 m
200 m
200 m
200 m
Northrop
Grumman
Wind Model
Results
100 m
100 m
100 m
200 m
100 m
Inertial Wind
from In-Situ
Data and Cloud
Base Altitude
Physical
Wind
Vector
Wind Vector and
Cloud Data Used to
Verify Northrop
Grumman Model
Wind Vector
of in-situ
data
6
Functional Block Diagram
Northrop
Grumman Wind
Model
GPS
Power
Module
Inertial
U-,V-,WWind Vector
Field
GPS
Coordinates
14.8V
5V
Post Processing
Algorithm
Speed
Controller
Serial
Command
PWM
PWM
Pixhawk Flight
Controller
14.8V
Aircraft
State &
Wind
Pressure
Motor
Antenna
Delivery System
9V
Arduino Due
Electrical Power
System
Analog
Voltage
Inertial
Navigation
System
SPI
Thermistor
Analog
Pressure
Transducers
Air
Pressure
5-Hole Probe
Elevon
Servos
Manual
Commands
Electrical Power
System
SD Card
Measurement System
Aircraft State
& Wind
Pressure
Relative
Wind
The Measurement
System is packaged
in the Delivery System
7
Functional Block
Diagram Continued
X
Cloud Base
Camera Field
of View
Camera Field
of View
Northrop Grumman
Wind Model
Battery
Cloud Base Altitude
& Footprint
Computer with Post
Processing Algorithm
Power
Power
Vertical
Camera
.RAW Image
Left and Right
.RAW Images
Internal SD
Card
Vertical
Camera
.RAW Image
Internal SD
Card
Cloud Observation System
Battery
8
Critical Project Elements
CPE
Requirement
Motivation
Obtaining a COA
4.1.1
UAV cannot legally fly without a COA
Determining Flight Path and
maintaining it in flight
1.1.1.1, 3.1
To meet required spatial and temporal
measurement resolution
Rapid Prototyping 5-hole probe
1.2
Used to measure wind
Calibrated 5-hole probe
1.2.3
Need to geometrically calibrate the probe to
accurately measure wind
Aircraft State Knowledge
1.2.2
Needed to convert relative wind to inertial wind
Wind Post Processing Algorithm
1.2.1
Needed to convert relative wind to inertial wind.
Cloud Observation Algorithm
2.2.2
Deliver cloud data within required error bounds
9
Detailed Schedule up to TRR
• Calibration fell behind
schedule due to issues
with electrical and
mechanical design
▫ However reducing
the number of data
points allowed us to
get back on track
and collect all
necessary data
▫ Only calibration
algorithm remains
and will be
completed this week
• Assembling the UAV
was moved forward
due to extra resources
available
MSR
TRR
10
• UAV testing
also moved
forward
▫ Early flight
testing allows
for margin due
to inclement
weather and
resources
needed
▫ Allows for more
resource
allocation to
TRR
Cloud
Observation
System
11
Detailed Test Schedule
• All tests have built in margin due to unforeseen errors and availability of
facilities and resources
▫ This is especially true with all flight related tests. Each flight test below
should only take 1 day.
TRR
12
Delivery System Test Overview
Manual and Autonomous Control Tests,
Range Test, Software in the Loop
Manual Flight Test, Autonomous Flight
Test, Flight Path Test
Final Data Collection Flight
Complete
In Progress
Scheduled in Future
● Purpose: To transport the
Measurement System through the
measurement cylinder within the
required 30 meter spatial
resolution and 15 minute time
limit
● Status: UAV is flight ready.
Ground tests have been
accomplished and flight tests can
now commence.
13
Manual Flight Test
Purpose:
To validate that power consumption is adequate for
flight time. Building block for autonomous flight
Requirement:
3.1 – Delivery system must fly for 15 minutes
Method:
Collect Power Consumption Data during climb and
descent.
Facilities:
Table Mountain, Pilot James Mack
Expected Results:
Power consumption during flight is similar to
predicted. Verify battery will last for >20 minutes
during data collection. Aircraft is shown to be
airworthy.
Impact:
Aircraft is ready for autonomous flight testing.
14
Manual Flight Test Procedure
• Procedures:
1. Setup ground control station (GCS) in open area
close to launch and landing sites.
2. Perform ground testing of control response prior to
launch.
3. With pilot ok, launch aircraft.
4. Pilot performs helix climb and descent at flight
velocities.
5. Instruct pilot to land aircraft.
15
Autonomous Flight Test
Purpose:
Validate autopilot control of aircraft during
ascent and descent during loiter.
Requirement:
3.1 – Delivery system must fly for 15 minutes
Method:
Record ascent and descent rates during
autonomous flight.
Facilities:
Table Mountain, Pilot James Mack
Expected Results:
Ascent and descent rates within 1 m/s of
expected 1.66 m/s.
Impact:
Aircraft is ready for flight plan testing.
16
Autonomous Flight Test Procedure
• Procedures:
1.
2.
3.
4.
5.
6.
Setup GCS in open area close
to launch and landing sites.
Perform ground testing of
control response prior to
launch.
Load box pattern and loiter
waypoint to Pixhawk.
With pilot ok, launch aircraft.
Instruct pilot to transition to
autonomous flight
After flight path completion,
instruct pilot to land aircraft.
Overview
Schedule
Delivery
System
Measurement
System
Cloud
Observation
System
Budget
17
Flight Path Test
Purpose:
Validate ability to fly data collection flight
path.
Requirement:
3.1 – Delivery system must fly
measurement system to all measurement
locations in the 15 minute requirement
Method:
Command modified data collection flight
path and record path and compare to SITL
flight plan.
Facilities:
Table Mountain, Pilot James Mack
Expected Results:
Vertical velocity as a function of time differs
by no more than 1 m/s from SITL flight
path, loiter radius remains constant.
Impact:
Aircraft is ready for data collection.
Overview
Schedule
Delivery
System
Measurement
System
Flight Path
Cloud
Observation
System
Budget
18
Flight Path Test Procedure
• Procedures:
1.
2.
3.
4.
5.
6.
7.
Setup GCS in open area close to launch and landing sites.
Perform ground testing of control response prior to
launch.
Load modified flight path.
Run through preflight checklist.
With pilot ok, launch aircraft.
Instruct pilot to transition to autonomous flight
After flight path Completion, instruct pilot to land
aircraft.
Overview
Schedule
Delivery
System
Measurement
System
Cloud
Observation
System
Budget
19
Measurement System Test Overview
Verification of Individual Components,
Wind Tunnel Characterization
INS test, Calibration of Probe
Verification of Calibration, Flight
Testing
Complete
In Progress
Overview
Scheduled in Future
Schedule
Delivery
System
● Purpose: Verify the Measurement
System will satisfy the 1 m/s
accuracy of inertial wind
measurements
● Status: INS test and calibration
will be completed this week.
Verification of calibration and
flight testing with the
measurement system is scheduled
for next week. Everything is on
schedule.
Measurement
System
Cloud
Observation
System
Budget
20
Calibration of 5-hole probe
Purpose:
Calibrate probe by creating matrix of reference
pressure coefficients
Requirement:
1.2.3 – Probe must be calibrated to determine
relative wind
Method:
Collect 5 hole pressure data at a 90° span of yaw
and 180° span of roll angles
Facilities:
ITLL Wind Tunnel
Expected Results:
Total pressure measured by probe is within 20%
of the wind tunnel total pressure
Impact:
Probe can now determine U-,V-,W- wind velocity
Overview
Schedule
Delivery
System
Measurement
System
Cloud
Observation
System
Budget
21
Calibration data collection
● Procedures:
1.
2.
3.
4.
5.
6.
7.
Set probe to -45° yaw angle and zero roll
Set wind tunnel to 25 m/s. Take data from
BLISS Arduino and wind tunnel at the same
time
Roll the probe 5°
Set wind tunnel to 25 m/s. Take data from
BLISS Arduino and wind tunnel at the same
time
Repeat steps 3 and 4 until a roll angle of
180° is reached
Set roll back to 0°. Move yaw angle 5°
Repeat steps 2-6. Positive 45° is the final
yaw angle
Overview
Schedule
Delivery
System
Roll
● Animation of probe moving in
tunnel
Yaw
Measurement
System
Cloud
Observation
System
Budget
22
Calibration of 5-hole probe
•
•
5
3
Assumes ideal flow around an ideal two dimensional
cylinder
Comparison shows a similar trend between analytical and
wind tunnel data. The trend shown by the data is less
pronounced, possibly due to:
▫
▫
•
4
Analytical prediction of pressure on the probe developed to
give a baseline prediction of pressures
▫
1
Ideal 2D flow assumption vs. real 3D viscous flow
Imperfect geometry of the probe tip
Angles beyond 30° are not shown because analytical
prediction breaks down due to flow separation
▫
Analytical solution becomes less accurate approaching 30°
due to small flow separation
Overview
Schedule
Delivery
System
Measurement
System
Cloud
Observation
System
Budget
2
Probe tip
23
Calibration of 5-hole Probe
•
•
Pressure data meets expectation when
rolling the probe at a fixed yaw angle
Plotted data at 20° yaw, where flow has not
separated from the probe tip
▫ Port 5 remains unchanged because its
orientation relative to flow is fixed
during roll
▫ Pressure on ports 1-4 varies as the
ports are exposed to more or less of the
flow
Overview
Schedule
Delivery
System
1
4
5
3
Measurement
System
Cloud
Observation
System
Budget
2
Probe tip
24
Verification of Calibration
Purpose:
Verify flow velocity components measured by
probe match expected results from a known
flow.
Requirement:
1.2.3 – Probe must be calibrated to determine
relative wind
Method:
Following Calibration Data Collection
Procedure, Set probe at various yaw/roll
orientations, measure pressures
Facilities:
ITLL Wind Tunnel
Expected Results:
Pressure data will correspond to orientation
within 3.0° in alpha and 3.5° in beta
Impact:
Probe can now determine U-,V-,W- wind
velocity, ready for testing
Overview
Schedule
Delivery
System
Measurement
System
Probe tip
β
V∞
α
w
u
v
Cloud
Observation
System
Budget
25
INS Test
Purpose:
Verify the INS is outputting values corresponding to known
orientation
Requirement:
1.2.2 – Record necessary aircraft state data
Method:
Mount INS in moving vehicle, measure Euler angles, angular
rates, GPS position and velocity in known orientations
Expected Results:
GPS will display the route and velocity the car drives. The
Euler angles will match up to output from potentiometers.
Impact:
INS is now ready for flight testing
Overview
Schedule
Delivery
System
Measurement
System
Cloud
Observation
System
Budget
26
INS Test
● Procedures:
1. Drive to the corner of Jay Road and
Highway 119 and pull over
2. Verify that GPS is functioning
3. Verify Euler angles under static
conditions
4. Drive down Highway 119 to Niwot
on cruise control
5. Verify GPS position and velocity
agree with route and speedometer
6. Repeat route
7. Verify Euler angles correspond to
readings from potentiometer
accounting for elevation change in
the road
Overview
Schedule
Delivery
System
Measurement
System
Cloud
Observation
System
Budget
27
UAV Interface and Flight Testing
Purpose:
Verify measurement system components
measure expected values when UAV flies
Requirement:
1.2 – 1 m/s accuracy in U-,V-,W- wind velocities
Method:
Following the Manual Flight Test Procedure, fly
delivery system with 5-hole probe/transducers,
thermistor and INS collecting data
Expected
Results:
Measurement system reports wind data
consistent with ground based weather station.
Impact:
Delivery and Measurement Systems are ready
for final data collection
Overview
Schedule
Delivery
System
Measurement
System
Cloud
Observation
System
Budget
28
Cloud Observation System Test Overview
● Purpose: Verify the COS can
measure cloud base altitude within
10% error as defined by REQ. 2.2.3
● Status: All parts machined,
cameras hacked; Small scale
testing expected completion 3/13
Benchtop Testing
Small Scale Testing
Final Configuration Test
Complete
In Progress
Overview
Scheduled in Future
Schedule
Delivery
System
Measurement
System
Cloud
Observation
System
Budget
29
COS Small Scale Testing
Purpose:
Verify the COS meets 10% error requirement on ¼ scale
test
Requirement:
Method:
2.2.3 – Less than 10% error for clouds up to 2 km
Picture
Set up system on angle to view points on buildings that
are up to 0.25 km away.
Expected Results:
Measurements will be within 10% error requirement
Impact:
Algorithms can be improved without special access to
University facilities until results verified on a small scale
Overview
Schedule
Delivery
System
Measurement
System
Cloud
Observation
System
Budget
30
COS Small Scale Testing
Procedures:
1. Level and align COS brackets, tilt
each same amount until building in
view
2. Run imaging scripts on both
cameras, run for 3 min
3. Process image sets
4. Compare COS measurements to
actual measurements
Camera Mount
Overview
Schedule
Delivery
System
Measurement
System
Cloud
Observation
System
Budget
31
COS Final Configuration Testing
Purpose:
Verify the COS meets 10% error requirement
on a full scale test
Requirement:
2.2.3 – Less than 10% error for clouds up to 2
km
Method:
Measure cloud base altitude from top of Duane
Physics, compare results with CU ATOC
Ceilometer
Facilities:
Roof of Duane Physics Building
Expected
Results:
COS altitude measurements are within 10% of
ATOC ceilometer measurements
Impact:
COS is verified to measure cloud base altitude,
ready for final data collection
Overview
Schedule
Delivery
System
Measurement
System
Cloud
Observation
System
Budget
32
COS Final Configuration Testing
Procedures:
1. Test on a day with cumulous clouds
2. Setup COS on roof of physics
building, align mounts and level
3. Start imaging scripts, run for 3 min
4. Process image sets
5. Compare COS measurements
ceilometer data
Overview
Schedule
Delivery
System
Measurement
System
Cloud
Observation
System
Budget
33
COS Final Configuration Testing
● Compute distance measurement
with COS
Dist =
f *b
disparity
up to 2km
● COS measurements expected to
be within 10% of ceilometer
reading
ATOC
Ceilometer
Overview
Schedule
Delivery
System
Measurement
System
Cloud
Observation
System
40m
Bliss COS
Budget
34
Budget Update
•
•
•
•
•
Estimated Expenses at time of CDR: $4708.29
Total Expenditures thus far: ~ $4300
Remaining Margin: ~ $700
Notable savings from shipping budget allocation
Many unexpected small purchases have led to considerable additional spending
Budgeted
Delivery System
Under(Over)
$
1,265.00
$
1,061.62
$
203.38
Measurement System $
2,562.47
$
2,412.90
$
149.57
Cloud System
$
355.97
$
241.90
$
114.07
Shipping
$
500.00
$
73.10
$
426.90
-
$
491.47
$
-491.47
$
711.90
$
Additional Expenses
Margin
Overview
Actual
Schedule
$
Delivery
System
292
Measurement
System
Cloud
Observation
System
419
Budget
35
Budget Update
Expenses To Date
Measurement System,
$2,413
Future Expenditures
Cloud System, $242
Shipping, $80
Additional Expenses,
$491
Remaining Funds,
$462
Margin, $712
Replacement Materials,
$50
Delivery System,
$1,062
Overview
Schedule
Delivery
System
Additional
Hardware, $50
Measurement
System
Cloud
Observation
System
Printing, $50
Poster, $100
Budget
36
Summary
• Delivery System status:
▫
▫
Ground tests have been completed.
UAV is flight ready and can begin tests when James Mack is available and weather is good.
• Measurement System status:
▫
▫
All calibration data has been taken. Algorithm for the data sets is in progress and on schedule.
INS test to be completed this week.
• Cloud Observation System status:
▫
▫
Cameras have been hacked and the mounts have been assembled.
Final distancing algorithm is in progress and the CU ATOC ceilometer validation test is
scheduled in 3 weeks.
• The margin in the budget is currently at $712 and a final planned margin is $462
37
Acknowledgements
• We would like to thank all of the PAB, our
advisor Dr. Gerren, our customer Dr. Diener
from Northrop Grumman, Trudy Schwartz,
Bobby Hodgkinson, Matt Rhode, James Mack,
and Gabe LoDolce for all their help in
preparation for this TRR.
38
Questions?
39
Back Up Slides
40
Motivation
• Northrop Grumman Atmospheric Boundary
Layer Model Verification
▫ Boundary layer inertial wind data, cloud base
altitude used in verification
• Boundary Layer Wind Model Applications:
▫ Airborne pollution monitoring
▫ Prediction of forest fire advances
▫ Facilitating soldiers in battle
Overview
Schedule
Mechanical
Electrical
Software
Budget
41
Experimental
Setup
Cloud observations
constrained to the
measurement
cylinder’s vertical
projection
Legend
BLISS Measurement
and Delivery System
Data points –
Spaced at most
30m radially in
3D space
Overview
100 m
Physical Wind
Velocity Vector Field
(u-,v-,w-)
200 m
≤ 30 m
Cloud Observation
System stereovision
cameras
Schedule
Mechanical
Atmospheric clouds
located high above
test volume
In-Situ relative wind
velocity data collection
Electrical
Software
Budget
42
Levels of Success
Delivery System
Level 1:
Certified to operate in an
airspace defined as a
cylinder with a 100 meter
radius and 200 meter
height above ground level.
Level 2:
Executes flight plan following
points spaced no more than
30 meters apart spanning the
defined airspace in the 15
minute time limit.
Level 3:
Execute level 2 flight
plan with Measurement
System onboard and
collecting data
Motivation: The measurement system needs to be
transported through the measurement cylinder to meet
special and temporal requirements.
Overview
Schedule
Delivery
System
Measurement
System
Cloud
Observation
System
Budget
43
Levels of Success
Measurement System
Level 1:
Wind measurement system
collects relative wind data
with resolution of 0.1
meter/second.
Level 3:
Level 2:
Deliver U-, V-, W- inertial
Post-process the relative
wind velocity vector field
wind data from a ground test
with temporal and spatial
to compute the U, V, W
location for each
inertial wind velocity vector
measurement accurate
components.
to 1 m/s with a
resolution of 0.1 m/s.
Motivation: Provide Northrop Grumman with data
precise enough to verify a boundary layer wind model.
Overview
Schedule
Delivery
System
Measurement
System
Cloud
Observation
System
Budget
44
Levels of Success
Cloud Observation System
Level 1:
Image the cloud footprint
above a 100 meter radius
cylinder at 1/4 Hz for a 15
minute period.
Level 2:
Level 3:
System is tested in full scale Deliver time-stamped cloud
to take distance
footprint images and cloud
measurement with less than base altitude measurements
10% error up to 2km
at 1/4 Hz during the 15
minute test period.
Motivation: Provide Northrop Grumman with cloud observation
data to correlate with wind vector field measurements.
Overview
Schedule
Delivery
System
Measurement
System
Cloud
Observation
System
Budget
45
Resource Allocation
46
Ground Testing
• Preliminary and preflight
ground testing conducted to
assure aircraft response to
manual and autopilot control.
• Will test elevon directional
response to control input and
prop rotational direction.
• Ground testing ensures
readiness for flight testing.
Overview
Schedule
Delivery
System
Measurement
System
Cloud
Observation
System
Budget
47
Ground Test Procedure
•
•
•
•
•
Arm Aircraft Control Surfaces in Manual Mode
Input Roll Command and Record Elevon Response
Input Pitch Command and Record Elevon Response.
Switch to ALTCTL Mode
Pitch Aircraft and Record Elevon Deflection. Note:
Deflection will be opposite motion to restore aircraft
to level flight.
• Roll Aircraft and Record Elevon Deflection.
48
Range Test
• Conducted to verify maximum
radio range is greater than the
maximum distance BLISS DS
will travel from the ground
station.
• Will be conducted on Kittredge
Field.
• Range test prepares for flight
readiness.
Overview
Schedule
Delivery
System
Measurement
System
Cloud
Observation
System
Budget
49
Range Test Procedure
•
•
•
•
Setup GCS on North East Corner of Kittredge Field.
Disconnect Motor from ESC.
Arm Aircraft.
Have Test Assistant Carry Aircraft Away From GCS while
inputting RC control to elevons every 5 seconds.
• When Test Assistant is unable to observe RC input
return to GCS.
• If Link is Lost from GCS to Aircraft at Any Point,
Measure that Distance as Max Range.
50
Preflight Checklist
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
****** Airframe ******
☐ ☐ Ensure fuselage is fully assembled, screws
tightened, comm antenna bends forward
☐ ☐ Check Prop For Damage and Loose Bolts
****** Auto-Pilot ******
☐ ☐ Turn on Aircraft and start Qgroundcontrol
☐ ☐ Connect Aircraft to Qgroundcontrol
☐ ☐ Verify Battery Level Acceptable for Flight
☐ ☐ Ensure Data and Comm Link
☐ ☐ Ensure Correct Airframe Configuration
☐ ☐ Ensure RC Remote calibrated and assigned
correctly
☐ ☐ Ensure Sensors are connected and calibrated
☐ ☐ Verify Mission Waypoints
☐ ☐ Save Mission Waypoints and Gains
☐ ☐ Verify GPS Lock
☐ ☐ Verify Manual Controls
☐ ☐ Check pitot port by blowing into it and seeing
the airspeed response
•
•
•
•
•
•
•
•
•
****** Prelaunch *********
☐ ☐ If using Autonomous Takeoff ensure waypoint
reachable and loiter waypoint exists
☐ ☐ Arm Control Surfaces
☐ ☐ Recheck control surface deflections in manual and
ALTCTL
☐ ☐ Load vehicle on catapult
☐ ☐ Enter Manual Mode
☐ ☐ Signal ready to backup pilot; if autonomous launch,
pilot will switch to Auto Mode; clear for launch
****** Pre-Autonomous Flight Checks ******
☐ ☐ 15 s after liftoff, verify Flying mode
☐ ☐ Verify that aircraft heading displays correctly and that
GPS is locked
☐ ☐ Track first autonomous waypoint (usually home loiter)
☐ ☐ Inform pilot of expected autonomous behavior
☐ ☐ Direct pilot to desired handoff flight path and
authorize handoff to autonomous flight
51
Flight Plan Simulation
• Skywalker X8 has been implemented into
Software in the Loop (SITL)
• 4 Helix Flight Path can be completed without
stalling
Overview
Variable
Max Value in SITL
Flight Time
12.5 Minutes
Pitch Angle
11°
Roll Angle
31°
Schedule
Delivery
System
Measurement
System
Cloud
Observation
System
Budget
52
Autopilot Flight Plan Design
Switch to
Autopilot
Control
Overview
Enter
Ascending
Helix 1
Schedule
Delivery
System
Complete
Ascending
Helix 1
Measurement
System
Cloud
Observation
System
Enter
Descending
Helix 1
Budget
53
INS Test Stand Drawing
Overview
Schedule
Mechanical
Electrical
Software
Budget
54
Wind Tunnel Calibration Stand Drawings
Overview
Schedule
Mechanical
Electrical
Software
Budget
55
Wind Tunnel Calibration Stand Drawings
Overview
Schedule
Mechanical
Electrical
Software
Budget
56
Wind Tunnel Calibration Stand Drawings
Overview
Schedule
Mechanical
Electrical
Software
Budget
57
Wind Tunnel Calibration Stand Drawings
Overview
Schedule
Mechanical
Electrical
Software
Budget
58
Wind Tunnel Calibration Stand Drawings
Overview
Schedule
Mechanical
Electrical
Software
Budget
59
Wind Tunnel Calibration Stand Drawings
Overview
Schedule
Mechanical
Electrical
Software
Budget
60
Wind Tunnel Calibration Stand Drawings
Overview
Schedule
Mechanical
Electrical
Software
Budget
61
Measurement System Test - completed
• Wind tunnel characterization test completed and data presented in MSR
• Electrical component verification completed:
▫
▫
Bench top testing of pressure transducers
Wind tunnel testing of incorporated transducers, probe, and tubing
• Calibration stand function testing completed:
▫
▫
▫
Stand fit with wind tunnel base
Probe range of motion
Data verification of integrated system
Overview
Schedule
Delivery
System
Measurement
System
Cloud
Observation
System
Budget
62
Port orientation to the flow
Flow
1
4
5
2
3
Higher Pressure
Lower Pressure
ψ
5-hole probe
Overview
Schedule
Delivery
System
Measurement
System
Cloud
Observation
System
Budget
Probe tip
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Purpose of Calibration
• Calibration is necessary to determine the unknowns of
the flow
▫ Angularity
▫ Total Pressure
• Calibration creates a dataset for comparison to
determine unknowns
▫ The five pressures measured on the probe are unique to a
certain total pressure and angularity
▫ Trend fitting matches the 5 pressures to the most similar
form the calibration set to determine unknowns
Overview
Schedule
Delivery
System
Measurement
System
Cloud
Observation
System
Budget
64
Measurement System: Pitot Tubes –
Calibration
• The 5 pressure readings from the probe (one from
each port) can be related to the orientation of the
probe through non-dimensional coefficients
• To do this:
▫ Independent non-dimensional coefficients are
calculated as a function of the 5 recorded
pressure values from the probe
▫ dependent non-dimensional coefficients are
calculated as functions of total pressure and
static pressure. Coefficients are stored in a
matrix.
• During testing, the independent coefficients act as
look-up tables, which allow determination of
orientation, total pressure and static pressure.
Overview
Schedule
Delivery
System
Measurement
System
Independent coefficients
𝑝2 + 𝑝3 + 𝑝4 + 𝑝5
𝑞 = 𝑝1 −
4
𝑝2 + 𝑝4 − 𝑝5 + 𝑝3
𝑏∅ =
2𝑞
Dependent coefficients
𝑝2 + 𝑝5 − 𝑝4 + 𝑝3
𝑏𝜃 =
2𝑞
𝑝1 − 𝑝𝑡
𝑞
𝐴𝑡 =
𝐴𝑠 =
𝑞
𝑝𝑡 − 𝑝𝑠
Cloud
Observation
System
Budget
65
Angularity Test
• At zero yaw angle, rolling the
probe would show if there is
an angularity in the wind
tunnel
• The trend shown is not
consistent with an angularity,
but can be attributed to
imperfect mounting of the
probe
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INS Factory Calibration
• All sensors (accelerometers, gyroscopes,
magnetometers) are calibrated for axis misalignment,
scale factor, and bias at the manufacturer.
▫ Calibration is stored onboard and applied in real time
during operation
• The performance specifications for the IMU and GPS are
validated through ground and air vehicle testing against
high-end fiber optic gyro based INS units at the
manufacturer
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