Notes on the 'argos' decode program for PMEL/MBARI EqPac

Program:  argos

Purpose:  Decode data received via System ARGOS into its constituent
          sensor values.  This program can operate in one of several
	  modes.  Depending on the command-line switch, it can recognize
	  data sent from Service Argos (default mode), or decode data
	  gathered with a local ARGOS receiver (-d or -n switches)

Usage:  argos [-b] [-c cfg_file] [-d] [-n]  <infile >outfile

	-b prints messages with checksum errors
	-c specifies an alternative configuration file
	-d is for a local ARGOS receiver in diagnostic mode
	-n is for a local ARGOS receiver in normal mode

	By default, the program assumes that the data came from Service
	Argos, does not print messages with checksum errors, and uses
	configuration file /oasis/cfg/argos.cfg (see below).  All the
	above can, of course, be modified in source code.

	Also note that the program takes input from standard-in and writes
	to standard-out.  It was done this way to facilitate using it as
	a filter to process incoming mail.  To use it on files, redirect
	stdin and stdout.

Background
This software is a derivative of software that is used on the OASIS project
at MBARI for decoding data from a rather extensive and varied set of sensors
(28 different types at last count), gathered via local packet radio.  As
such, it contains some baggage that would seem unneccessary.

In particular, the source code has some remnants of routines for creating
separate files for the various sensors, and carries with it a configuration
file structure that's more complex than necessary.  In the OASIS model,
the configuration file contains actual calibration information only for
the internal analog ports, and has pointers to other files for calibrations
for other individual sensors.  In the 'argos' software, the only other sensor
with calibration information is the PRR Spectroradiometer, but for
compatibility with our other software, we've kept this in a separate file.


Source Files

Makefile - The make file for this software.  Type 'make argos' to make the
	software.  The Makefile has rules for making all our other OASIS
	sotware as well, but you can ignore this, since you don't have those
	sources.

	There are several things in here that are particular to our
	environment of HP-UX, which you'll undoubtedly need to change.
	These include:  -Aa flag to the compiler - this tells HP's cc to
	use ANSI C mode.  -D_HPUX_SOURCE - this seems to be required in
	HP-land to bring in the ANSI and POSIX flavors of include files
	(e.g., stdio.h, time.h, etc).  Shouldn't be necessary for other
	environments.  -lM flag to linker - this brings in the math library
	for things like exponentials.  And of course you'll probably have
	the tools (cc etc) in different locations.

decode.h - This contains various definitions about data structures in the
	OASIS data stream.  Mostly irrelevant to the data structures used
	for ARGOS data, but contains a couple of relevant definitions.

argos.h - Contains data structure definitions for ARGOS data.  Also has some
	stuff that was more relevant for encoding the data in the first place,
	but nevertheless very relevant.

argos.c - The main source file.

file.c - This source file was lifted from our 'extract' program, which takes
	the OASIS data stream (in uuencoded format) and creates numerous
	output files.  Most of the code here is irrelevant to the 'argos'
	program.  The only code used here is to read the configuration files.

ac9.c - Only the decode_ac9_temp() function is used, since OASIS calculates
	the ratios for the spectral data before sending on ARGOS.

spec.c - Decodes the spectroradiometer data.  This file actually contains
	decode routines for three different types of spectroradiometers,
	only one of which is used for 'argos' -- decode_prr().

mbari/types.h - Contains data type definitions for MBARI's standard style
	of C, which this was written in.  You'll get used to it.

mbari/const.h - Some standard constants.


Configuration Files
argos.cfg - The main configuration file for this program.  It contains
	calibration information about the analog ports in the OASIS can,
	and also points to the calibration file for the spectroradiometer.
	Analog calibrations are of the form:
	analog a b c d units
	analog is one of several keywords understood
	a b c d are calibration constants for the equation
	output = ((a * counts) + b) * c + d
	Units is the output units, as an ASCII string.

specprr.m2 - The calibration file for the PRR-600 spectroradiometer.
	Format is described in the header to this file.


Directory Structure

For maximum compatibility, you'll want to name your base directory /oasis
and your configuration directory /oasis/cfg.  I also normally have directories
/oasis/src, /oasis/argos (for data), etc.  The only directory that's hard
coded is the default configuration directory, /oasis/cfg.  All other directory
names are arbitrary.  To change the name of the config directory, edit the
three "*_DIR" defines in file.c.  If you change its location, also edit
file argos.cfg so that it points to the correct location of the specprr.m2
calibration file.