Space Weather Lab GNSS Reflectometry for Studies of...
Transcript of Space Weather Lab GNSS Reflectometry for Studies of...
Space Weather
Lab
GNSS Reflectometry for Studies of Surface Ice And
Water Conditions
Roohollah Parvizi, Boris Pervan and Seebany Datta-Barua.
Illinois Institute of Technology
November 7, 2018 1
Supported by: NASA award NNX15AV01G
Space Weather
LabOutline
• Motivation ‒ Why GNSS-R
• Objective‒ Detecting GNSS-R
• Background‒ Delay Doppler Map
• Method ‒ What are our sensors
‒ Data Campaigns
‒ Signal Processing
• Results
• Conclusion
November 7, 2018 2
Space Weather
LabMotivation
November 7, 2018 3
Icy road
[2]: https://www.news-journal.com/news/police/icy-roads-run-out-of-wreckers
[1] [2]
[1]: https://www.bikebandit.com/blog/black-ice-the-invisible-winter-threat
Space Weather
LabMotivation
November 7, 2018 4[3]: https://www.wsj.com/articles/laser-eyes
[4]: https://www.teslarati.com/tesla-lidar-sensors-spotted-testing-palo-alto/
[5]
[3]
[4]
[5]: https://www.detroitnews.com/story/business/autos
Space Weather
LabMotivation
LiDAR disadvantages:
▪ Expensive, costly.
▪ Unreliable for water surface and breaking waves.
▪ It is affected by rain.
▪ Low operating range (500-2000m).
November 7, 2018 5
Space Weather
LabMotivation
Can we do better with GNSS?
▪ Lower cost.
▪Widespread coverage and availability.
▪Unaffected by precipitation and cloud cover.
▪Potentially better resolution.
November 7, 2018 6
Space Weather
LabGNSS-Reflectometry
November 7, 2018
GNSS-R:
• The study of the
characteristics of
a reflected signal
7
Space Weather
LabObjective
November 7, 2018 8
Satellite
𝑃𝑅𝑁𝑖
Satellite
𝑃𝑅𝑁𝑗
Power and Electronics
Verification sensors
• Detect reflected GNSS signals from the water/ice surface.
• Verify GNSS-R.
Space Weather
LabGNSS Reflection Signal
November 7, 2018
SP
𝛼𝑟 𝛽𝑖
Glistening Zone
Sensor
suite Satellite
𝑃𝑅𝑁𝑖
𝛼𝑟 = 𝛽𝑖
Specular Point(SP) :The point on
the surface where the incident
and reflected angles are equal
9
Verification sensors
Space Weather
LabGlistening Zone
November 7, 2018 10
Receiver
Glistening Zone
Receiver
Glistening Zone
Receiver
Space Weather
LabDelay Doppler Domain
November 7, 2018
Specular Point(SP)
Sensor
suite
Satellite
𝑃𝑅𝑁𝑖
East
North
11M. Martin-Neirea, A Passive Reflectometry and Interferometry System.
Iso-Range line
Iso-Doppler line
Space Weather
Lab
Spatial Domain andDelay Doppler domain
November 7, 2018 12
C/A
code
chips
delay
Doppler
frequency
y
x
SP
Iso-Range line
Iso-Doppler line
delay
Scattered Power
Space Weather
LabSensor Suite
November 7, 2018 13
Reflect
antenna
Direct
antenna
Universal software
radio peripheral
(USRP)
Space Weather
LabSensor Suite
November 7, 2018 14
Reflect
antenna
LiDAR
Camera
Weather
Station
Space Weather
LabTest Locations
November 7, 2018
Test 1,3 Locations
IIT
15
Test 4, 5
Locations
Test 2 Location
Space Weather
LabTest 2 Location
November 7, 2018 16
𝑆𝑒𝑛𝑠𝑜𝑟𝑑𝑖𝑟𝑒𝑐𝑡𝑖𝑜𝑛
𝑁𝑜𝑟𝑡ℎ
𝜙 = 2080
Space Weather
LabTest 5 Location
November 7, 2018 17
𝜙 = 600
𝑆𝑒𝑛𝑠𝑜𝑟𝑑𝑖𝑟𝑒𝑐𝑡𝑖𝑜𝑛
𝑁𝑜𝑟𝑡ℎ
Space Weather
LabData Campaigns Info
November 7, 2018 18
Data campaign info Test 02 Test 05
Date Tue Jan 23 14:35:48 2018 Thu Jul 05 12:13:28 2018
Sensor Location
Latitude: 41.8388924° 𝑁 Latitude: 41.84066 ° 𝑁
Longitude: 87.603140° W Longitude: 87.60698° W
Height:3 𝑚 Height: 3 𝑚
Sample rate 5 𝑀𝐻𝑧 5 𝑀𝐻𝑧
USRP_dir RF gain 31 𝑑𝐵 31 𝑑𝐵
USRP_ref RF gain 31 𝑑𝐵 31 𝑑𝐵
USRP_dir inline gain 0 𝑑𝐵 30 𝑑𝐵
USRP_ref inline gain 30 𝑑𝐵 40 𝑑𝐵
Look direction(azimuth angle) 2080 (southwest) 60𝑂 (northeast)
Condition Ice Water
Space Weather
LabPost-Processing
November 7, 2018 19
• Verification:
– Evaluate surface condition with weather station.
– Determine where SPs are.
– Compare SPs with LiDAR.
• Detection:
– DDM for SP on the water/ice.
Space Weather
LabPost-Processing
November 7, 2018 20
Data Field
campaign
Approximate sensor location
Almanac info
LiDAR range intensity
Compute SPENU SP-LiDAR
Map
Select SV whose DDM is
desiredDDM
Verification
Detection
Space Weather
Lab
November 7, 2018 21
Sky Plot and SP-LiDAR, Test 2 (ice)
Space Weather
LabSky Plot and SP, Test 5 (water)
November 7, 2018 22
(m)(m
)
Space Weather
LabSP-LiDAR Map
November 7, 2018 23
Θ = 450 LiDAR
Parallel to the dock
Perpendicular to the
dock
LiDAR direction
Perpendicular to the
LiDAR direction
LiDAR Field of vision
(± 15° Vertical FOV)
“PRN 28 is reflecting off the water”
(m)
(m)
Space Weather
Lab
Incoherent DDM for PRN 28 Test 5 (water),Method 1
November 7, 2018 24
Reflected Signal Direct Signal
[7]:R.Parvizi, H. S. Zadeh, L. Pan, B. Pervan, S. Datta-Barua, ” Multi-sensor Study of Lake Michigan’s Surface using GNSS-Reflectometry”, Proceedings of the 29th International Technical Meeting of The Satellite Division of the Institute
of Navigation (ION GNSS+ 2018), Miami, Florida, September 2018
Space Weather
LabDDM-Processing
Problem:
‐Weak and noisy signal: direct signal not acquired by SDR, reflected signal band unexplained.
Solution:
• Use auto-correlation peak to test the direct signal for acquisition.
‐Method 2: Incoherent integration.
‐20 ms, 100 ms, 500 ms and 1s
‐Method 3: Coherent integration
‐Coherently 10 ms
‐Method 4: Differentially coherent integration
• Generate reflected DDMs for the Method (4) that successfully acquires direct
signals.
November 7, 2018 25
Space Weather
LabMethod 2: Incoherent DDM Processing
November 7, 2018 26
Incoming signal
𝑒−𝑗𝑤𝑡
900
𝐼
𝑄
Correlator
Correlator
Coherent
integration
Coherent
integration
2
2
Incoherent
integration
Space Weather
LabMethod 3: Coherent DDM Processing
November 7, 2018 27
20 msOf
data
Second10msOf
data
First 10msOf
data
Results for D1 = 𝑃1
Results for D2= 𝑃2
D1
D2
Pick data set that has the
maximum power.
Coherent integration
Coherent integration
Space Weather
LabMethod 4: Coherent differential integration
November 7, 2018M. H. Zarrabizadeh and E. S. Sousa, “A Differentially Coherent PN Code Acquisition
Receiver for CDMA Systems”, IEEE TRANSACTIONS ON COMMUNICATIONS, VOL. 45, NO. 11, NOVEMBER 199728
Incoming signal
𝑒−𝑗𝑤𝑡
900
𝐼
𝑄
Correlator
Correlator
Coherent
integration
Coherent
integration
2
2
𝑌𝑘
𝑌𝑘−1∗
𝑍−1
. 2
𝑍𝑘
Space Weather
LabEvaluate Methods
for Direct signal at high and low elevations, Test 5
November 7, 2018 29
SKY plot
based on almanac infoSKY plot
based on real GPS data
Space Weather
Lab
Autocorrelation of Direct Signal, PRN 28
November 7, 2018 30
Incoherent integration,
method 2
Coherent integration,
method 3
Result: Methods 2 and 3 each result in acquiring the high elevation
direct signal.
Space Weather
Lab
Low elevation satellite, PRN 22, Direct signal
November 7, 2018 31
Incoherent integration,
method 2
Coherent integration,
method 3
Result: Methods 3 does NOT result in acquiring the low elevation
direct signal.
Space Weather
Lab
Low elevation satellite, PRN 22, Direct signal
November 7, 2018 32
Coherent differential integration,
method 4Result: Method 4
results in acquiring
the low elevation
direct signal and high
elevation direct signal
(not shown).
Next: Use Method 4
to generate DDM for
the reflected signal.
Space Weather
Lab
Method 4: Coherent differential DDM for PRN 28 Test 5 (water)
November 7, 2018 33
Reflected Signal Direct SignalAcquired in
C/A and
Doppler.Band in C/A
space partly
mitigated.
Space Weather
Lab
Method 4: Coherent differential DDM for PRN 22 Test 2 (ice)
November 7, 2018 34
Reflected Signal Direct Signal
Space Weather
LabConclusion
• Coherent, non-coherent, and coherent differential methods were studied for both direct and reflected GNSS signals.• Coherent differential method did a good job acquiring the low elevation satellite direct
signal.
• We generated coherent differential DDMs for the reflected water/ice surface.
• Future work:• Further analysis of coherent differential DDMs.
• Synchronization of multiple sensors.
• Combination of signal processing methods.
• Using accurate clock for USRPs, such as GPSDO.
• Additional data campaigns throughout 2018!
November 7, 2018 35
Space Weather
LabAcknowledgment
November 7, 2018 36
Houshine Sabbagh Zadeh,
Li Pan,
Yang Su and
Ningchao Wang
for their advice and
technical support.
November 7, 2018 37
Thank YOU.
Extra Slides
November 7, 2018 38
Space Weather
Lab
Method 4: Coherent differential DDM for PRN 28 Test 5 (water), K=2
November 7, 2018 39
Reflected Signal Direct SignalAcquired in C/A and Doppler.However, reflected
peak chip and Doppler change with k.
Space Weather
LabMethod 2 DDM for PRN 28 Test 5 (water)
November 7, 2018 40
Reflected Signal,500 ms Reflected Signal,1000 ms
Result: Reflected signal assumed comparable in noise to low-elevation direct signal. Methods 2 and 3 do NOT result
in a correct DDM (i.e., peak is not at the specular point).
Space Weather
Lab
Method 3 Coherent DDM for PRN 28 Test 5 (water), 10 ms
November 7, 2018 41
Reflected Signal Direct Signal
Space Weather
Lab
Method 4: Coherent differential DDM for PRN 28Test 5 (water)
November 7, 2018 42
Reflected Signal Direct Signal
Result: Method 3 results in a DDM at the specular point (C/A chip 867). However, band in C/A still exists in the reflected DDM only.
Space Weather
Lab
Low elevation satellite, PRN 3,Direct signal
November 7, 2018 43
Coherent
autocorrelation, 1ms
Coherent
autocorrelation, 10ms
Space Weather
LabLow elevation satellite, PRN 3
November 7, 2018 44
Coherent differential
Autocorrelation , 1ms , K=1
Coherent differential
Autocorrelation , 1ms , K=2
Space Weather
Lab
Incoherent DDM Processing, previous work: “Method 1”
November 7, 2018
20 msOf
data
Second10msOf
data
First 10msOf
data
Coherent integration
Results from 1st ms
10th
ms
1st
ms
Coherent integration
Results from 10th ms
Coherent integration
Results from 1st ms
10th
ms
1st
ms
Coherent integration
Results from 10th ms
Results from1st ms
Results from 2nd ms
Results from 10th ms
𝑓1
45
D1
D2
𝑃𝑖𝑛 =
𝑖=1
10
𝑃𝑖