Subject: [IGSMAIL-163] GPS Global Network Advisory
From: Ulf J. Lindqwister/JPL
Date: 8 JAN 1993 17:49:10

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IGS Electronic Mail        8-JAN-1993 17:49:10       Message Number 163
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From:	 Ulf J. Lindqwister/JPL
Subject: GPS Global Network Advisory: Kokee antenna to be moved
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The GPS receiver (Rogue SNR-8) at Kokee, hawaii, has had numerous
problems with power interruptions, severe multipath and physical
obstructions (nearby cranes) causing losses of lock. The power
interruptions are due to the after-effects of the hurricane which
hit Kauai a few months ago. Moreover, a 34 m VLBI antenna is being
built ~30 m from the GPS antenna causing severe blockage and multipath
problems. For the near-term the antenna will be moved to a more benign
location to maintain the site as a tracking site and for the long-term
the antenna will be placed on a geodetic monument again. The process of
moving the antenna to a better place will occur in two stages as follows:

1. On January 28, 1993, we are planning to move the antenna away from the
34 m VLBI antenna to a temporary site. This should significantly
reduce signal blockage and multipath and improve the receivers
tracking performance. After this date, data from
Kokee should NOT be held fixed at the old locations coordinates
until further notice. Hence during this period the Kokee site
should only be used for tracking support - not as a fiducial.

2. We are currently exploring two possible permanent locations for
the Kokee site and once the new site have been selected and checked
out (monumentation, infrastructure support, etc.) we will move the
antenna to this new, permanent location. A site tie will be conducted
to the VLBI monument so that the site can become a fiducial GPS site
once again.

Let me know if this plan causes any undue hardship upon anyone.

Regards,

- Ulf

Ulf J. Lindqwister
GPS Networks & Operations Group
Jet Propulsion Laboratory
4800 Oak Grove Dr.
Pasadena, CA 91109

(818) 354 1734
(818) 393 4965, FAX
[email-masked]