Sodankylä Geophysical Observatory


The following are the technical parameters and specifications of the Kilpisjärvi Atmospheric Imaging Receiver Array (KAIRA).


Up-to-date technical information on KAIRA, including real-time monitoring data, is now available from the Technical Details pages.


Location Kilpisjärvi
Country Finland
Operated by Sodankylä Geophysical Observatory
Receiver Units (RCUs) 96
Remote Station Processor (RSP) boards 12
RCU modes used 0,3,4,5,6,7
RCU modes available, but not used 1,2
Sample clock frequency 160 or 200 MHz
ADC bits 12-bit
Subbands (frequnecy channels) 512
Beamlets transport bit-mode dependent

Array parameters

The following are the parameters on an array basis. Note that it is possible to mix parts of the array for combined experiments.

Array parameters LBA HBA
Number of antennas 48 48
Antenna type Inverted-V dipoles 16-element tiles
Polarisation per antenna 2 2
Array layout sparse, quasi-random segmented rectangular
Array physical size (approx.) 34 m diameter 30 x 50 m
Array alignment symmetrical 314 degrees
Minimum frequency 10 MHz 110 MHz
Maximum frequency 90 MHz 270 MHz
RCU modes RCU3 & RCU4 RCU5, RCU6 & RCU7
Beam-forming digital analogue in each tile
digital over array
Elevation limit 20 degrees 20 degrees
Longitude of array centre (deg East) 20.7620758 20.76103311
Latitude of array centre (deg North) 69.0707445 69.0710561
Altitude of array centre (m, Finnish reference) 493.123 495.086
Geocentric-X coordinate (m) 2136833.225 2136818.264
Geocentric-Y coordinate (m) 810088.740 810038.592
Geocentric-Z coordinate (m) 5935285.279 5935299.531

See also:

Radar parameters

Because the KAIRA system is often used in conjunction with the EISCAT VHF radar at Ramfjordmoen, near Tromsø, the following information may also be useful.
Please note that KAIRA is an independent facility to EISCAT and time allocatedon one facility does not guarantee time on the other

VHF transmitter direction 313.95 degress
VHF transmitter frequencies 222.8 - 225.4 MHz

  • KAIRA technical document: KAIRA-SGO-TEC-146
See also:

Data products

The following is a rough guide to the sorts of data products that are available. Note that additional facilities might be available for specialised experiments. Potential observers are encouraged to discuss their requirements with the KAIRA team to ensure optimal data for their experiment.

Data product Ext.Description
Subband statistics SST all 512 subbands, min. 1-second integration
Beamlet statistics BST typically 244 or 488 beamlets, min. 1-second integration
Cross correlation statistics XST single subband, min. 1-second integration
Array covariance cubes ACC cross-correlations, stepped subbands, 1s integration only
Transient Buffer Board pages TBB Transient Buffer Board data
Transient Buffer Board raw data -- UDP streamed data
Beamlet raw data -- UDP streamed data

See also:

Last modified: 13 February 2020, 12:08:25.

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