[IGSMAIL-2039] Radio noise suppressed at Petropavlovsk
Grigory
Grigory
Tue Oct 13 02:13:45 PDT 1998
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IGS Electronic Mail Tue Oct 13 2:13:45 PDT 1998 Message Number 2039
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Author: Grigory Steblov and Mikhail Kogan
Subject: Radio noise suppressed at Petropavlovsk
PS TRACKER ID: PETR
DOMES No.: 12355M001
LOCATION: Petropavlovsk-Kamchatka, Kamchatka Peninsula, Russia
NEDA: Northern Eurasia Deformation Array created and run by
RUSEG: Russia/US Experiment on Geodynamics by GPS Technology.
NEDA operational control is provided by RDAAC:
Regional GPS Data Acquistion/Analysis Center, Moscow, Russia
(contact Grigory Steblov: steblov at ria.ipmnet.ru)
****************************************************************************
We are glad to report that there are NO MORE problems
with the intense radio noise at IGS station in Petropavlovsk-Kamchatka.
The noise was suppressed completely although it took 3 months to overcome
the problem.
****************************************************************************
IGS station PETR worked without any problems for 8 months, since October '97.
- In our igsmail of 28-Jul-98, we stated the following:
"We recommend TO DISREGARD ANY DATA collected at PETR since 27-JUL-98 (DOY 208)
until further notice.
REASON: Continued problem with locking enough satellites at local (Kamchatka)
daily hours (See our IGSMail of:
Mon Jul 27 9:01:03 PDT 1998 / Message Number 1964)."
- The problem started 9-Jul-98 and it was caused by the new antenna of RosTelecom
about 7 km away from our GPS antenna. 2-3-4 satellites only were locked sometimes
for 2-3 hours degrading the data for purposes of IGS. We discussed the situation
with experts at UNAVCO, JPL, and MIT. UNAVCO provided to us replacement antennas
and cables. Yet the problem persisted. We also replaced the TurboRogue receiver
with the Ashtech Z12, because of its better SNR, but it helped insignificantly.
- A combination of three actions solved the problem last week:
1) Setting up of the grounded, flat, steel shield vertically, at a distance
of 0.96 m from the antenna axis.
Dimension of the shield: 0.63 x 0.32 m.
Its upper edge is almost flush with choke rings so that we do not expect
any significant multipathing.
2) Shifting of the antenna to a new location at a distance of 8.25 m from
the old mark (PETR).
3) Setting the antenna lower by 0.53 m.
As a result, we now have mostly 7-8 satellites locked with the 8-channel
TurboRogue all 24 hrs, and never less than 6.
**********************************************************
- We labelled the new mark: PET1.
The same receiver and antenna are used at PET1 as was used at PETR.
PETR does not function since DOY 283.
Instead, PET1 does function smoothly since DOY 281.
**********************************************************
The GPS mark PET1 exists since 1996.
Both marks, PETR and PET1 were tied with synchronous GPS observations in 1997 and
again last week. We give below the differences in X/Y/Z (GAMIT solution from
two 24-hrs sessions in each year):
Year PETR minus PET1
---- -----------------------------------------------
DX (m) DY (m) DZ (m)
------ ------ ------
1997 +3.8297 +7.1705 +1.3853
1998 +3.8300 +7.1719 +1.3857
=======================================================================
MEAN: +3.8298 +7.1712 +1.3855
We also processed one 24-hrs session (DOY 284: 11-Oct-98) at PET1 by GAMIT,
including five additional IGS stations: FAIR, USUD, IRKT, MAG0, YAKZ.
Results are VERY GOOD:
Postfit nrms: 0.19243E+00
ONE-WAY POSTFIT RESIDUAL STATISTICS: Pass 22
---------------------------------------------
RMS by site and satellite (mm): Pass 22
RMS IT Site All 01 02 03 04 05 06 07 08 09 10 13 14 15 16 17 18 19 21 22 23 24 25 26 27 29 30 31
RMS 22 PET1 6.2 6 7 6 7 6 7 6 6 5 5 5 5 6 5 7 6 7 5 5 6 9 7 6 6 6 5 5
RMS 22 ALL 7.1 6 7 7 8 7 8 7 7 6 7 7 6 7 7 7 7 7 7 7 6 10 9 8 7 7 6 6
DATA AMOUNTS (Good: # good data; Gap: # deleted in gaps; BF: # bias flags < 2*max separation)
PET1 PN01 654 26 0 PN02 717 34 1 PN03 665 1 0 PN04 590 1 0
PN05 647 21 0 PN06 612 24 0 PN07 622 15 3 PN08 685 8 0
PN09 686 4 1 PN10 631 6 0 PN13 596 22 0 PN14 565 12 2
PN15 572 32 2 PN16 617 17 2 PN17 703 15 1 PN18 736 39 0
PN19 733 26 0 PN21 593 18 1 PN22 626 3 0 PN23 828 26 0
PN24 732 13 1 PN25 659 27 0 PN26 665 4 0 PN27 579 26 2
PN29 709 58 0 PN30 676 18 0 PN31 671 0 0
* * *
- The 24-hrs rinex files from PET1 since DOY 284 are made available as earlier
for PETR by arrangements of RDAAC with world data centers.
- We will apply for IERS Domes Number of PET1 immediately.
Finally, we thank Dmitry Frolov and Sergei Egorov, electronics engineers of RDAAC,
who made most of the job on saving the IGS station at Petropavlovsk together
with Vasiliy Levin and Vilory Bakhtiyarov, geodesists operating the Kamchatka
GPS Center. Advice kindly provided by workers of UNAVCO, JPL, Scripps, and MIT,
and by Ted Koczynski at Lamont, is appreciated.
Regards,
-- Grigory Steblov (steblov at ria.ipmnet.ru)
-- Mikhail Kogan (kogan at ldeo.columbia.edu)
[Mailed From: Mikhail Kogan <kogan at ldeo.columbia.edu>]
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