preliminary results from the afrl-nasa w/v-band
TRANSCRIPT
Preliminary Results from the AFRL-NASA W/V-BandTerrestrial Link Experiment in Albuquerque, NM
www.nasa.govNational Aeronautics and Space Administration
Michael Zemba, James Nessel, Jacquelynne Houts, Nicholas Tarasenko, Steven Lane, David Murrell
Presented by Michael ZembaNASA Glenn Research CenterAdvanced High Frequency Branch
Wave Propagation in Terrestrial, Oceanic and Atmospheric Environments
2016 IEEE International Symposium on Antennas and Propagation • Fajardo, Puerto Rico • June 29th, 2016
Presentation Overview
2
1. Motivation & Experiment Goals
2. Site of Study
3. Receiver Site (COSMIAC)
4. Transmitter Site (Sandia Crest)
5. Instrumentation
6. Preliminary Results
7. Solar Influence
8. Concluding Remarks
Wireframe schematic of the WTLE receiver front end electronics.
Motivation & Goals
Experiment Motivation & Goals
• To assess the impact of atmospheric effects on links operating in the V and W-band (rain attenuation, scintillation, depolarization, etc.).
• To develop physical models to improve predictions of atmospheric attenuationwithin the V/W-band.
• To provide a testbed for RF propagation measurement instruments & techniques.
• To assess optical link performance with a side-by-side link in tandem with theexisting RF link.
3
WTLE transmitter front end electronicsand lens antennas.
Site of Study
4Sandia Crest(Photo: Google Earth)
COSMIAC (University of New Mexico)(Photo: Google Earth)
N
Receiver
Site UNM / COSMIAC (Roof)
Latitude 35.054031° N
Longitude 106.619443° W
Altitude 1.596 km
Installation Date September 2015
Transmitter
Site Sandia Crest
Latitude 35.215128° N
Longitude 106.451245° W
Altitude 3.239 km
Beacon Freqs.72 GHz84 GHz
Installation Date September 2015
Path
Azimuth 40.444°
Elevation 3.984°
Path Length 23.55 km
Rx Tx
AlbuquerqueN e w M e x i c o
R e c e i v e r T r a n s m i t t e r
Receiver Site (COSMIAC)
Transmitter Site (Sandia Crest)
Weather Instrumentation
Pressure Sensor: Young BPV3000
Temperature/Humidity Sensor: Young 41382VC
Tipping Bucket: Young 52203
Anemometer: Young 05178A
Beacon Receivers
Instrumentation
Antenna Gain 45.6 dBi (V / W-band)
Dynamic Range 70 dB (V) /68 dB (W)
Co/Cross-Polarization Isolation 13 dB (V) / 20 dB (W)
Polarization LHCP
Sampling Period 0.1 sec (10 Hz) 7
Laser DisdrometerThies Clima 5.4110
Block Diagram
17 18 19 20 21
-90
-80
-70
-60
-50
-40
-30
-20
-10
Ch
an
nel
Po
wer
(dB
m)
Time (UTC)
V Co
V X
W Co
W X
17 18 19 20 211499
1499.2
1499.4
1499.6
1499.8
1500
1500.2
1500.4
1500.6
1500.8
1501
Beaco
n F
req
uen
cy (
kH
z)
Time (UTC)
9
Under normal operating conditions, the Vand W-band receivers track theirrespective beacon signals using amodified Quinn-Fernandes frequencyestimation algorithm. The cross-polarization signal is tracked from thecurrent co-polarization frequency
When attenuation approaches the noisefloor (below a given power threshold),the frequency estimate is replaced by anaverage of the frequency estimate priorto the fade. This allows for a slightimprovement in dynamic range duringthe beginning and end of deep fades.
Signal lock is immediately regained whenthe signal reappears above the noisefloor.
System Performance
Tracking Threshold
Beacon tracked from frequency estimate prior to rain fade.
Loss of Lock
Clear Sky Day (2015-09-30)
06 07 08 09 10 11 12 13 14 15 16 17 18 19-40
-35
-30
-25
-20
-15
-10
Ch
an
nel
Po
wer
(dB
m)
Time (UTC)
V Co
V X
W Co
W X
06 07 08 09 10 11 12 13 14 15 16 17 18 191.5
2
2.5
3
3.5
4
4.5
5
5.5
AG
A (
dB
)
Time (UTC)
Meteorologically Derived AGA
V
W
Diurnal variations in atmosphericgaseous absorption (AGA) observedin timeseries attenuation on clear-skydays.
Photo Credit: NASA
18 19 20 210
2
4
6
8
10
12
14
Rain
Rate
(L
iqu
id)
(mm
/ h
r)
Time (UTC)
Deep Rain Fade (2015-11-04)
18 19 20 21-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
Ch
an
nel
Po
wer
(dB
m)
Time (UTC)
V Co
V X
W Co
W X
Strong rain event exceeds dynamicrange of receiver on all channels.
Liquid Precipitation
Photo Credit: Albuquerque Journal
Rain on Path (2015-10-03)
15 16 17 18 19 20 21-80
-70
-60
-50
-40
-30
-20
-10
Ch
an
nel
Po
wer
(dB
m)
Time (UTC)
V Co
V X
W Co
W X
15 16 17 18 19 20 210
5
10
15
20
25
Rain
Rate
(L
iqu
id)
(mm
/ h
r)
Time (UTC)
Rain at receiver subsides while rainfade continues, indicating continuedrain along the path.
Liquid Precipitation
Photo Credit: NOAA
Snow / Depolarization (2015-12-26)
18 19 20 21 22 23 00-40
-35
-30
-25
-20
-15
-10
Ch
an
nel
Po
wer
(dB
m)
Time (UTC)
V Co
V X
W Co
W X
18 19 20 21-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
Ch
an
nel
Po
wer
(dB
m)
Time (UTC)
V Co
V X
W Co
W X
18 19 20 21 22 23 000
0.2
0.4
0.6
0.8
1
1.2
1.4
Rain
Rate
(S
oli
d)
(mm
/ h
r)
Time (UTC)
Strong depolarizing effectsobserved on both V and W-bandchannels during solid precipitation(snow) event.
Solid Precipitation
Photo Credit: Albuquerque Journal
Cloud Event (2016-01-09)
06 07 08 09 10 11 12 13 14-50
-45
-40
-35
-30
-25
-20
-15
Ch
an
nel
Po
wer
(dB
m)
Time (UTC)
V Co
V X
W Co
W X
06 07 08 09 10 11 12 13 140
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Rain
Rate
(L
iqu
id)
(mm
/ h
r)
Time (UTC)
Strong fluctuations on both V andW-band channels with noprecipitation while clouds obscurethe peak of Sandia Crest.
No Precipitation
Photo Credit: NASA
18 19-70
-60
-50
-40
-30
-20
-10
Ch
an
nel
Po
wer
(dB
m)
Time (UTC)
V
W
16 17 18 19-18
-17
-16
-15
-14
-13
-12
-11
-10
-9
Ch
an
nel
Po
wer
(dB
m)
Time (UTC)
V
W
10-3
10-2
10-1
100
101
10-4
10-2
100
102
104
Frequency (Hz)
Pow
er
spectr
al density (
dB
2/H
z)
V
W
Attenuation (-20 dB/dec)
Scintillation (-80/3 dB/dec)
10-3
10-2
10-1
100
101
10-4
10-2
100
102
104
Frequency (Hz)
Pow
er
spectr
al density (
dB
2/H
z)
V
W
Attenuation (-20 dB/dec)
Scintillation (-80/3 dB/dec)
Measurement Spectral Density
15
1 hr
3 hrs
Atten.
Scint.
0 10 20 30 40 50 60 70 800.1
1
10
100
October
November
December
January
February
March
April
May
Total
WTLE V-Band Attenuation CDFs (2015 - 2016)
V-Band Co-Pol Attenuat ion [dB]
Per
cen
t o
f T
ime
Val
ue
is E
xce
eded
0 10 20 30 40 50 60 70 800.1
1
10
100
October
November
December
January
February
March
April
May
Total
WTLE W-Band Attenuation CDFs (2015 - 2016)
W-Band Co-Pol Attenuat ion [dB]
Per
cent
of
Tim
e V
alue
is E
xce
eded
Attenuation Statistics
16
Oct. Nov. Dec. Jan. Feb. Mar. Apr. May. Total
V 36.533 dB 31.983 dB 18.722 dB 11.457 dB 1.379 dB 0.763 dB 10.247 dB 5.971 dB 16.845 dB
W 36.967 dB 41.500 dB 24.953 dB 14.614 dB 3.249 dB 1.686 dB 17.278 dB 11.264 dB 22.065 dB
Perc
en
t o
f Ti
me
Val
ue
is E
xce
ede
d
Perc
en
t o
f Ti
me
Val
ue
is E
xce
ede
d
Attenuation
V-Band W-Band
Attenuation [dB] Attenuation [dB]
Attenuation
99% Attenuation(Exceeded 1% of the Time)
Large month-to-month variability, upto 35.8 dB (V) and 39.8 dB (W)between the best and worst months.
* Worst Month* Best Month
99% 99%
0 2.5 5 7.5 10 12.5 15 17.5 200.01
0.1
1
10
100
October
November
December
January
February
March
April
May
Total
WTLE V-Band Attenuation CDFs (2015 - 2016)
V-Band Co-Pol Attenuation [dB]
Per
cen
t o
f T
ime
Val
ue
is E
xce
eded
Rain Rate Statistics
17
Oct. Nov. Dec. Jan. Feb. Mar. Apr. May. Total
2.14% 1.31% 0.79% 1.08% 0.07% 0.05% 2.19% 3.22% 1.05%
5.656 mm/hr 4.106 mm/hr 3.399 mm/hr 1.112 mm/hr 0.000 mm/hr 0.000 mm/hr 5.179 mm/hr 0.197 mm/hr 3.513 mm/hr
Perc
en
t o
f Ti
me
Val
ue
is E
xce
ede
d
Measured Rain Rate (Liquid Precipitation)
Rain Rate [mm / hr]
In total, rain was observed 1.05% ofthe time over the 7 month period(approx. 61.48 hours).
99.9% of the 7 month period, the rainrate was less than 3.513 mm / hr.
In other words, the rain rate was lessthan 3.513 mm/hr for 90.48% of timeswhen rain was measured.
99.9%
99.9% Rain Rate(Exceeded 0.1% of the Time)
Occurrence of Rain
* Worst Month* Best Month(s)
Radome Warming (2015-10-12)
Rx
Tx
Ch
ann
el P
ow
er (
dB
m)
W-Band
Daily co/x power disturbances were observed, particularly on the W-band,and correlated with solar position. This was remedied by replacing thetransmitter radome with a more suitable εr=1 dielectric.
Concluding Remarks & Future Work
Conclusions
• The WTLE terminal has been operational since October 2015, collecting attenuation, scintillation, and depolarization data across a 26 km link in Albuquerque, NM. As of this presentation, nearly nine months of data have been collected.
• For 99% of the time, the observed attenuation was less than 16.845 dB (V) and 22.065 dB (W). The worst months in terms of the attenuation were October (V) and November (W), while the best month for both was March (V and W).
• Large monthly variability was observed, with a difference of up to 35.8 dB (V) and 39.8 dB (W) month-to-month.• Rain was observed 1.05% of the time over the analyzed 7 months (61.5 hrs). The rain rate only exceeded 3.5 mm/hr for 5.8 hrs
over the 7 months.
Future Work
• Weather station along the path is currently being installed to assess weather conditions along the link.• Tandem optical link is planned for the near future to characterize optical propagation with concurrent RF data. 19
Thank You!
Appendix Charts
21
Contact Information
James Nessel
Principal Investigator, RF Propagation Task
216.433.2546
Michael Zemba
Research Engineer
216.433.5357
Jacquelynne Morse
Research Engineer
216.433.5468
22
NASA Glenn Research Center
21000 Brookpark Rd. MS 54-1
Cleveland, Ohio 44135, USA
0 10 20 30 40 50 60 70 800.1
1
10
100
V-Band
W-Band
WTLE Isolation (2015 - 2016)
V-Band X-Pol Attenuation [dB]
Per
cen
t o
f T
ime
Val
ue
is E
xce
eded
Tx Air & Plate Temperatures and PWM Output
09/27 09/28 09/29 09/30 10/014
4.5
5
5.5
6
6.5
7
7.5
8
8.5
9
Air
Co
ntr
ol
Ou
tpu
t (V
)
Time (UTC)
09/27 09/28 09/29 09/30 10/0131.4
31.6
31.8
32
32.2
32.4
32.6
Air
Tem
p.
(Co
ntr
ol)
(°C
)
Time (UTC)
09/27 09/28 09/29 09/30 10/0137.97
37.98
37.99
38
38.01
38.02
38.03
38.04
Pla
te T
em
p.
(°C
)
Time (UTC)
09/27 09/28 09/29 09/30 10/018
10
12
14
16
18
20
Pla
te C
on
tro
l O
utp
ut
(%)
Time (UTC)
Power Detector Variance & PWM Outputs
09/27 09/28 09/29 09/30 10/0135.7
35.75
35.8
35.85
35.9
35.95
36
36.05
36.1
36.15
36.2
Air
Tem
p.
(RF
Co
ver)
(°C
)
Time (UTC)
09/27 09/28 09/29 09/30 10/01330
340
350
360
370
380
390
400
410
420
430
W-B
an
d D
ete
cto
r (m
V)
Time (UTC)
09/27 09/28 09/29 09/30 10/014
4.5
5
5.5
6
6.5
7
7.5
8
8.5
9
Air
Co
ntr
ol
Ou
tpu
t (V
)
Time (UTC)
09/27 09/28 09/29 09/30 10/018
10
12
14
16
18
20
Pla
te C
on
tro
l O
utp
ut
(%)
Time (UTC)
Receiver Software
6 7 8 9 10 11 1210
11
12
13
14
15
16
TLE Transmitter Power Detectors
2015-09-29
Time (Hours UTC)
Pow
er
Dete
cto
r (d
B)
V
W
6 7 8 9 10 11 12-50
-45
-40
-35
-30
-25
-20
-15
-10
TLE W-Band Receiver Power (1Hz)
2015-09-29
Time (Hours UTC)
Am
plit
ude (
dB
)
Co
X
Tx Power vs. Rx Power (2015-09-29 0600 - 1200)
11 11.5 12 12.5 13 13.5 14-45
-40
-35
-30
-25
-20
-15
-10
-5
Tx
= 0.7896 dB
Rx
= 1.815 dBy
Co = 1.1894x + -32.8114
Tx
= 0.7896 dB
Rx
= 1.446 dBy
X = 0.44256x + -39.1026
TLE Transmitter Power Detectors
2015-09-29
Receiv
er
Pow
er
(dB
)
Transmitter Power Detector (dBm)
W Co
W X