Keywords : data, record

Data Record

One of the most important TECHSAS functionnality is to record acquired data. The record process can be run either on the station on which the acquisition processes run or on another station. The record process adress is entred by the user in the general configuration. Recording can be redundant (data is recorded twice at the same time, for security reasons).

Both path names where data is recorded are declared in the general configuration.

Data can be recorded in two formats : ASCII/NMEA or NetCDF.

NMEA record

Acquisition processes send to the record process UDP/IP frames with the following syntax:

$HEAD1,DATE,TIME,HEAD2,DATA1,DATA2,...<CR><LF>

Record process sort these frames according to their two headers HEAD1 and HEAD2 and record them in a file (one file for one sensor).

For each sensor, the user declares in TECHSAS configuration the following parameters:

  • NMEA headers (HEAD1 and HEAD2 in the preceeding example),
  • record period,
  • record path,
  • file extension.

example of a NMEA record file:

$PAMES,22/11/00,06:54:43.600,METEO, 0, 26.100, 26.900, 79.00,1013.00,0027.00,0000.0,
$PAMES,22/11/00,06:54:53.400,METEO, 0, 26.100, 26.900, 78.67,1013.00,0027.00,0000.0,
$PAMES,22/11/00,06:55:03.300,METEO, 0, 26.100, 26.900, 78.00,1013.00,0027.00,0000.0,
$PAMES,22/11/00,06:55:03.400,METEO, 0, 26.100, 26.900, 78.00,1013.00,0027.33,0000.0,

NetCDF record

TECHSAS can archive acquired data in a format based on NetCDF format. NetCDF is a binary and auto-descriptive format.

This format based on NetCDF has been specified by both Ifremer and SHOM. It is today used by both organizations.