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NATIONAL ASTRONOMY AND IONOSPHERE CENTER

RFI in the alpha band pass
Murray Lewis

Senior Research Associate Radio Astronomy Group


NATIONAL ASTRONOMY AND IONOSPHERE CENTER

Propose to cover
FCC frequency allocations in spectral region GPS Galileo PR Radars in band RFI Mitigation possibilities radar blankers! nine level sampling! algorithms! cross correlation between feeds Reinforcement of AO anti-RFI activity!


NATIONAL ASTRONOMY AND IONOSPHERE CENTER

The frequency range covered by alpha is from

1225 to 1525 MHz


NATIONAL ASTRONOMY AND IONOSPHERE CENTER



NATIONAL ASTRONOMY AND IONOSPHERE CENTER


NATIONAL ASTRONOMY AND IONOSPHERE CENTER

GPS L1, L2, L5
L5 L2 L1

General coverage -158 dBW Spot Beam -138 dBW

Alpha 1225 - 1525


NATIONAL ASTRONOMY AND IONOSPHERE CENTER

GPS
L1 & L2 -157 dBW for C/A -160 dBW for Y L5 -154 dBW 24 MHz, full time occupancy This is 6dB stronger than present L1 & L2 L5 spfd ~-205 dBW/m^2/Hz 1164-1188 MHz ~-197 dBW/m^2/Hz in center

5 - 8 satellites always available Also, of concern, GPS L3 circa 1381 MHz


NATIONAL ASTRONOMY AND IONOSPHERE CENTER

Galileo -- full set due 2008
E5A_E5B 1164-1215 MHz E6 1260-1300 MHz E2,L1,E1 1559-1591 MHz (WRC2000) (WRC2000)

Use of C_band under consideration To have 30 satellites, in 3 planes, inclination 56 deg 14 hr orbits, radius 23616 km Power 50 W amplifiers peak power 120 W


NATIONAL ASTRONOMY AND IONOSPHERE CENTER

Galileo

On orbit validation 2001-5 Deployment Commercial Ops. 2006-7 2008

2/4 satellites 26-28 sats

Concern is their presence at 1260-1300 MHz


NATIONAL ASTRONOMY AND IONOSPHERE CENTER

Details of Common/Unusual RFI Available on AO Web Page


NATIONAL ASTRONOMY AND IONOSPHERE CENTER

Hilltop Monitor 1200-1450 MHz


NATIONAL ASTRONOMY AND IONOSPHERE CENTER

Blanking San Juan Airport Radars? Examples Surroundings of 1400-1427 MHz band US has proposed a satellite system Uplink circa 1400, downlink circa 1427 MHz Timing explorer in Space Lab was at 1427 MHz L3 (GPS) at 1381 MHz


NATIONAL ASTRONOMY AND IONOSPHERE CENTER

Fractional occupation of 0.1 MHz bins


NATIONAL ASTRONOMY AND IONOSPHERE CENTER




400 0

0

500

1000

1500

2000

RATAN-500
20 0

1116+28

0

500

1000

1500

2000


NATIONAL ASTRONOMY AND IONOSPHERE CENTER

Arecibo anti-RFI activity
importance of L_band to alpha Do you want radar blankers How bothersome is the 1350 MHz birdie? Should you be using 9-level sampling? Algorithm development