During all this time the device worked
without any kind of problems. The baselines of H and Z-components of LEMI-008 magnetometer
for year 2000 are given in the Attachments 1, 2. The jump in the baselines is caused when
the magnetometer sensor was replaced at better peer in the hut (see Fig.1).
Taking into account that the obtained from
“Academic Vernadsky” station data proved the correspondence of baselines variations to
INTERMAGNET standard, in the autumn of year 2000 LCISR and BGS came to agreement to
transmit to LCISR the equipment for data loading and transferring via satellite. With
joint assistance of BGS, USGS and INTERMAGNET LCISR engineer Ye.Nakalov passed
successfully the probation period in BGS with the aim to learn the equipment and software.
After his return the search of the proper place at the station was done for the
possibility to install the transmitter antenna. It became clear that the elevation angle
of METEOSAT satellite visibility is closed with the continental mountains. Then USGS
efficiently changed the BGS transmitter to the system oriented to GOES-E satellite and Ye.
Nakalov managed to learn it in proper time.
In January, 2001 in “Fiberglass Hut” of
magnetic observatory “Argentine Islands” the equipment for satellite transmission of
magnetometer data of the type 3455A GIM (SYNERGETIC INTERNATIONAL), which provides the
communication via geostationary satellite GOES-E, was installed (see Fig.2). The
high-frequency 10 W 3421A GOES transmitter with the digital frequency tuning assures the
operation according to the established transmission mode and within the allowed
The functional diagram of the equipment
3455A GIM and magnetometer LEMI-008 installation in “Variometer Hut” and “Fiberglass
Hut” is given in Attachment 3.
After installation of 3455A GIM, from
March, 11, 2001, the permanent transmission of the LEMI-008 magnetometer data was begun,
which are cumulated on FTP-server after processing in the Canadian information center.
The received from 3455A GIM equipment data
is given in telemetric digits (TMD) which is necessary to transform into magnetic field
values (nT). It was realized by the TMD data comparison with nT data received directly
from magnetometer LEMI-008 for the same period by e-mail communication (Attachments
On the first diagram the fragment of
magnetic data record transmitted from 3455A GIM is shown (Att.4).
On the next two diagrams (Att.5,6) the
same data fragment is shown which was received from the magnetometer LEMI-008 by station
e-mail transmission every second (Att.5) and averaged for every minute (Att.6).
All diagrams are synchronized by time. On
the diagram of Att.5 one can see the high level of the interference at the station
territory. In particular, the regular minute marks with amplitude of ~0.4 nT come from the
For comparison the every minute records of
H, D, Z components transmitted via 3455A equipment and averaged for one minute data from
LEMI-008 scaled between each other are taken (Att.7, 8,9). One may note that the
difference between two sets of data gives comparatively small dispersion between data from
3455A and LEMI-008.
The calculated averaged transfer
coefficients (3455A/LEMI-008) are the following:
Channel H: 42 TMD/nT
Channel D: 40 TMD/nT
Channel Z: 39 TMD/nT.
The average dispersion of the
coefficients is no more than ± 1 TMD.
The example of transfer coefficient
dispersion for D channel is given on the diagram (Att.10).
The supposed reasons of the dispersion of
the transfer coefficient average values can be the following:
It is necessary to note that at the
obtained average value of transfer coefficient ~40 TMD/nT the maximal deviation is not
more than ± 4 TM digits, what corresponds to the specified resolution threshold ± 0.1 nT
of the magnetometer. So, it is recommended to accept the average mean of the transfer
coefficient equal to 40 TMD/nT for every component and to transform the information
transferred now (in TMD) to www into readings by the magnetic field (in nT).
The work planned for the future to rise
the magnetic data quality.
- To provide the reception of the digital magnetometer data
with 3455A GIM equipment via serial channel what will permit to transfer to INTERMAGNET
system the data measured directly with LEMI-008 magnetometer and to exclude the
interference inducing to analog connection channel between the magnetometer and the
- To install the equipment permitting to set the time every
24 hours in the automatic mode by GPS and to control the transfer parameters of 3455A
- To modernize the software of LEMI-008 magnetometer to make
possible the formation of data files which are necessary for transferring to 3455A.
- To organize the possibility of the distant control of
- To eliminate the minute interference with 0.4 nT amplitude
and 3 s duration which was observed in LEMI-008 data.
January-February 2001, Vernadsky Antarctic