• Antelope Release 5.5 Linux 2.6.32-220.el6.x86_64 2015-04-21

 

NAME

ia2orb - Acquire data from Internet Accelerometers into Antelope orbserver

SYNOPSIS

ia2orb [-kvV] [-p pfname] [-s statefile] [-t target] [-c cmdorbname] orbname

SUPPORT


Contributed code: NO BRTT support.
THIS PIECE OF SOFTWARE WAS CONTRIBUTED BY THE ANTELOPE USER COMMUNITY. BRTT DISCLAIMS ALL OWNERSHIP, LIABILITY, AND SUPPORT FOR THIS PIECE OF SOFTWARE.

FOR HELP WITH THIS PIECE OF SOFTWARE, PLEASE CONTACT THE CONTRIBUTING AUTHOR.

DESCRIPTION

The ia2orb utility acquires data from Internet Accelerometer (IA) dataloggers via the Internet Accelerometer relay server, placing the acquired data onto the Antelope orbserver specified by orbname. Files are converted from the original miniseed into orb packets by the Antelope miniseed2orb(1) program, which is called automatically by ia2orb. The stations to be acquired are specified by the ia_network array in the parameter file. See the PARAMETER FILE section below for complete details. Each station may have acquisition specified as off, on-demand, or continuous. If a station is marked for continuous acquisition, all files are downloaded from the instrument as they become available. If a station is marked for on-demand acquisition, files are downloaded only upon receipt of an acquisition command via the command-orb (usually put there by the iatrigger(1) or iarequest(1) applications), and only for files matching the requested point in time or time range for waveform data. The ia2orb application dynamically monitors its parameter file for changes to the ia_network array, so the ia2orb application does not need to be stopped and restarted if the status is changed for a given station.

OPTIONS

PARAMETER FILE

Parameter File Parameters

Parameter File Example


ssh 			ssh
scp 			scp
download_dir 		/tmp

reject_future_data_sec 	86400
reject_old_request_sec	129600
max_rangerequest_sec 	3600

ia_user 		seismology
relay_server_ip 	127.0.0.1

ia_network &Arr{
#
#sta    net  grid relay_server_ip    relay_port byteswap_timecorr  acquisition
#
PGC01   CN   NA   &relay_server_ip   99999   yes   continuous
}

EXAMPLE

The ia2orb program may be run from the command line in a shell with an ssh authentication agent, for example as follows:

% ssh-agent $SHELL
% ssh-add ~/.ssh/id_iauser
Passphrase:
% ia2orb -v ':@'

The following example shows how to trigger the acquisition of a segment of data across the network for a given time, by putting a command packet on the orbserver for the running ia2orb instance using the default target name of ia2orb:

%cat mycmd.pf
command acqnet
time 1177721659.872
%
% pf2orb -s ia2orb -p dlcm mycmd :
%

SEE ALSO

iarequest(1), iatrigger(1), orbserver(1), miniseed2orb(1), ssh(5)

BUGS AND CAVEATS

ia2orb is strongly bound to the current naming convention and timestamping patterns for files on the IA dataloggers. Changes to these conventions will invalidate data-acquisition assumptions made in the ia2orb code. ia2orb presumes the IA is configured to return time-series data in counts, not in physical units. ia2orb presumes the account and shell under which it runs are already authenticated for the ssh connections to the relay server. As a guideline only, one way to accomplish this when running from an interactive environment is by configuring an ssh agent:

% ssh-agent $SHELL
% ssh-add ./my_private_ssh_key_file
Passphrase:
%

The above example is only a guide to further exploration. The authentication mechanisms for running ia2orb (specifically, for running it continuously and in an automated sense under the Antelope real-time system) will have to be constructed to match the security policies of the site at which ia2orb is run. The intent here is to have the security engineering for the user's ssh connectivity be completely distinct from the internal engineering of the ia2orb program. For a few introductory suggestions on setting up password-less ssh logins, see the man-page ssh(5). For further information, consider referring to the book SSH, the Secure Shell: The Definitive Guide by Daniel J. Barrett, Richard E. Silverman, and Robert G. Byrnes, O'Reilly publications, 2005. ia2orb is currently set up to use only one relay server per station. In principle it would be possible to expand it to use multiple relay servers, falling back to second or third relay servers on failure of the first. The byteswap_timecorr capability was written as a workaround to a bug in the Internet Accelerometer acquisition code at the time of writing. It is no longer necessary to enable this for all instruments. The -k option keeps the original files downloaded from the IA. However, if the byteswap_msd_timecorr parameter is set, the byte-swapping is done in place on the files, so the files in the download_dir will be not quite identical to those on the IA itself. ia2orb will not repeatedly attempt to retrieve a given file from the IA if attempts to get that file are at first unsuccessful. The one exception to this is that if the file to be acquired is for a station in on-demand mode, if the failure to acquire is due simply to scp being unable to find or retrieve the file, and if the request time is within one IA block-size of the system-clock time, the relevant thread will estimate an amount of time to sleep for that station, then re-post the request. This will hold off requests for earlier data from the same station, however that data will still be requested after the sleep cycle elapses.

AUTHOR

Kent Lindquist
Lindquist Consulting, Inc.

Antelope User Group Contributed Software
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