1 u.s. study radar emission masks a review of the radar spectrum engineering criteria (rsec) robert...
TRANSCRIPT
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U.S. STUDY RADAR EMISSION MASKS
A Review of the Radar Spectrum Engineering Criteria (RSEC)
ROBERT L. HINKLE
United States Department of CommerceNational Telecommunications and Information Administration
Office of Spectrum Management
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PURPOSE
Ensure an acceptable degree of electromagnetic
compatibility among radar systems, and between such systems and those of other radio services sharing
the frequency spectrum.
Promote efficient use of the spectrum.
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RADAR CHARACTERISTICS ADDRESSED IN THE RSECEmission bandwidth (40 dB)
Emission levels
Tunability
Antenna patterns
Frequency tolerance
Receiver selectivity
Image and spurious rejection
Local-oscillator radiation
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RSEC EMISSION MASK
-100
-80
-60
-40
-20
0
20
-150 -100 -50 0 50 100 150
Criteria D
Criteria C
Criteria B
t = 1.0 s
tr = 0.05 s
PRR = 1000 PPS Average
Pp = 90 dBm (1 MW)
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REVIEW OF RSEC
Last major review of RSEC conducted in 1973-1977 time frame
New generation of radar systems more complex Waveform characteristics change pulse-to-pulse Dynamic PRF pulse trains
Trend toward solid state output devices
Increase in interference from radars
ITU-R Working Party 8B (Radiodetermination) has set up a radar group to investigate feasibility of more stringent emission masks than contained in ITU-R Recommendation SM1541, Annex 8, by 2006 Radiocommunication Assembly meeting.
Work Program developed by ITU-R Working Party 8B
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AIRPORT SURVEILLANCE RADAR(Klystron Output device)
ASR-8 (Channel A)
-120
-100
-80
-60
-40
-20
0
20
2550 2650 2750 2850 2950 3050 3150 3250 3350
Frequency, MHz
Rec
eive
d P
ow
er N
orm
aliz
ed t
o M
axim
um
(d
B)
Data
Mask 1
Mask 1: , t=0.6, tr=0.05, Bc=NA, d=NA, Bc=NA, N=1, P RR=1040, FL=NA, FH=NA, Bs=0, P t=27.195, P G=0., Bn(-20)=10.335, B(-40)=35.796, S=40., X(dB)=80.
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-100
-75
-50
-25
0
25
3600 3700 3800 3900 4000 4100 4200
B(-40 dB) = 25.3 MHzBn(-20 dB) = 7.3 MHz
w/ Filter
w/o Filter
RSEC-C
(S = 20)
Run Time: 5/21/98
80 dB Floor Level Scenario
(S = 40) Scenario
B (-40 dB) Mask
Bn (-20 dB) Mask Scenario
*Note: Assumptions gathered from data sheets rather than SPS Submission.
Non-FM Pulse RadarCriteria C category w/ 80 dB Floor (override)Pp = 89.29 dBm (850 kW)*t = 0.6s*tr = 0.1 s*PRR = 1125 PPS *Coaxial Magnetron Tube Type (w/ & w/o Filter)
Frequency, MHz
Rec
eive
d S
igna
l Lev
el, d
Bm
RADIONAVIGATION RADAR(Coaxial Magnetron W/WO Filter)
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RADIONAVIGATION RADAR(Coaxial Magnetron)
AN/SPS-64(V)
-140
-120
-100
-80
-60
-40
-20
0
20
2150 2650 3150 3650 4150 4650 5150 5650 6150
Frequency, MHz
Rec
eive
d P
ow
er N
orm
aliz
ed t
o M
axim
um
(d
B)
Data
Mask 1
Mask 2
Mask 1: , t=1, tr=0.1, Bc=NA, d=NA, Bc=NA, N=1, P RR=900, FL=NA, FH=NA, Bs=0, P t=17.324, P G=0., Bn(-20)=5.66, B(-40)=24.033, S=20., X(dB)=60.
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WEATHER RADAR(Klystron output Device)
NEXRAD Radar
-120
-100
-80
-60
-40
-20
0
20
2000 2500 3000 3500 4000 4500 5000 5500 6000 6500 7000
Frequency, MHz
Rec
eive
d P
ow
er N
orm
aliz
ed t
o M
axim
um
(d
B)
Data
Mask 1
Mask 1: , t=1.6, tr=0.1, Bc=NA, d=NA, Bc=NA, N=1, P RR=1304, FL=NA, FH=NA, Bs=0, P t=35.235, P G=0., Bn(-20)=4.144, B(-40)=15.5, S=40., X(dB)=80.
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OVERRVIEW OFRSEC CHANGES BEING CONSIDEERED
Add the following to Group A (Exempt from RSEC).
Maritime Radionavigation 2900-3100 MHz
Aeronautical Radionavigation and Radionavigation 5350-5470 MHz
Aeronautical Radionavigation 15.4-15.7 GHz
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OVERVIEW OF RSEC CHANGES BEING CONSIDERED
Group B (Criteria B)
Retain 40 dB bandwidth formulas
Assess feasibility of roll-off slopes of 30/40 dB per decade
Change X (dB) Level to 60 dB for near term, and consider phasing in X (dB) floor of:
X (dB) =10LogP(Watts) + 30Where: 60 dB ≤ X (dB) ≤ 80 dB
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OVERVIEW OF RSEC CHANGES BEING CONSIDERED
Group C (Criteria C)
Retain 40 dB bandwidth formulas
Assess feasibility of roll-off slopes of 30/40 dB per decade
Change X (dB) Level to 60 dB for near term, and consider phasing in X (dB) floor of:
X (dB) =10LogP(Watts) + 30Where: 60 dB ≤ X (dB) ≤ 80 dB
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OVERVIEW OF RSEC CHANGES BEING CONSIDERED
Group D (Criteria D)
Retain all of Criteria D except change harmonic levels to 80 dB New solid state radars can not meet Criteria D without waveguide
filter
Group E (Criteria E)
No proposed changes
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APPROACH
Develop a software program that will provide current and optional emission masks.
Identify, through measurements, emission characteristic of radars with various types of output devices and antennas.
Apply software program (emission masks) to measured emission characteristics to assess feasibility of establishing a more spectrum efficient emission mask.
Engage the radar manufacturers and radar output device manufacturers to identify state-of-the-art capabilities.
Through the IRAC/TSC, in coordination with Federal agencies reach agreement regarding draft revised emission masks for future radar systems.