###############################################################################
##									     ##
##	File:     README						     ##
##	Author:   Wolfgang Rupprecht <wolfgang@capsicum.wsrcc.com>	     ##
##	Created:  Sun Jan 24 21:22:28 PST 1999				     ##
##	Contents: Readme file for remote rtcm (DGPS) client program          ##
##									     ##
##	Copyright (c) 1999 Wolfgang S. Rupprecht			     ##
##									     ##
##	$Id: README,v 1.34 1999/02/27 21:14:32 wolfgang Exp $
###############################################################################

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation.  See the file COPYING for details.

The official dgps-ip web page is below.  Please check that for
updates, announcements etc.

	http://www.wsrcc.com/wolfgang/gps/dgps-ip.html

To obtain the latest copy of dgpsip, grab dgpsip-X.XX.tar.gz via your
favorate browser from:

	http://www.wsrcc.com/wolfgang/ftp/

To compile dgpsip:

	./configure
	make

To install dgpsip:

	make install

      	cat services >> /etc/services

	cd /dev
	ln -s tty00 gps

This assumes that tty00 is the tty you wish to plug the gps into.  Adjust to
taste.

To run dgpsip:

	dgpsip

	On older Garmin gps's (38, 12xl, 130) set the protocol to "RTCM/NMEA"
	On newser Garmin gps's (II, III) set the protocol to "NMEA/RTCM"

	On other gps brands set according to manufacturer's
	instructions for running the gps with an RTCM radio that
	requires no tuning instructions from the GPS.  You will need
	to set it to 4800-N81 (4800 baud, no parity, 8-bit data,
	1 stop-bit).  If the GPS has user selectable NMEA sentences
	one needs to turn on the GGA (aka. $GPGGA) sentence. 

	I'm told that the differential radio speaks the "Starlink"
        dialect of DGPS corrctions.  If the GPS has setting for Magnavox 
	or Starlink, you probably need the Starlink setting.  (Folks
	with concrete information -- please let me know if either one
	works, if Starlink works better etc.  I'll update this note
	then.)

As of version 1.15 dgpsip can optionally read the NMEA data stream
from the GPS and calculate the standard deviation.  It is best to configure 
the GPS to output NMEA, although this is strictly optional.

runtime options:

	-h host_name or ip_address to connect to
		default dgps.wsrcc.com

	-p port_name or port_number to connect to on remote machine.
		default number: 2101  
		default name: rtcm-sc104

	-o output_tty
		default: /dev/gps

	-v verbosity_level
		default: 0
		Verbosity = 1 prints version number.
		Verbosity = 2 prints a periodic accuracy and position report 
		Verbosity = 3 prints a per packet dot	
		Verbosity = 5 prints connection error msg.
		Verbosity = 10 prints per-packet byte counts.

	-d
		Decode rtcm stream and turn off tty output by default. 
		To run both decoder and tty output "dgpsip -d -o /dev/gps"

sanity test:

	As a sanity test (such as if dgpsip doesn't seem to be
	running) one can access the data stream directly from telnet
	as such:

		telnet dgps.wsrcc.com 2101

	You should see the raw binary rtcm-sc104 data stream sent to
	your terminal screen.

Position and accuracy report format: 

With a verbosity of -v2 or above dgpsip will calculate and print out
the averaged position and height, the number of sample points
collected, and the standard deviation of the position and height, the
average HDOP and the average number of satellites in view.  An
intentionally truncated copy of this report is also sent to the dgpsip
server.  The difference is that the position is only reported to the
dgpsip server to 2 decimal places (which corresponds to an accuracy of
+/- 1.5 miles).  Position reports occur at 32 sec, 64 sec, 128 sec,
256 sec and every new power of two thereafter.  This report allows for
automatic logging of how well the system is working in various parts
of the world as well as generating usage maps.  Look on the above http
web page for the latest statistics and usage maps in xearth marker
file format.

Here is what "dgpsip -v2" reports for WSRCC:

	R 37.55 -121.94 31.62 -- 512 4.51e-05 6.76e-05 6.30e+00 1.9 5.7

The fields are lat, lon, height (meters), number of samples, lat-sdev
lon-sdev, height-sdev, hdop, average-number-of-sats.

Troubleshooting problems with position reports not being generated:

Is the GPS in RTCM/NMEA mode?  The GPS must send out NMEA sentences
and must accept RTCM input.

Is the dgpsip NMEA parser parsing the output from your GPS?  Invoke as
"dgpsip -v20" and examine the transcript.  There should be a very
visible $GPGGA raw sentence spit out every 2 seconds, and directly
below that should be a second printout where the parser spits out what
it interpreted that sentence to mean.  If the first $GPGGA sentence
doesn't exits you have a cabling, baudrate, or GPS setup problem.  If
first exists but the second doesn't there is a parser problem.  Please
save a few repetitions of the output and mail them to me.  As of v1.24
the NMEA parser underwent a major change and its entirely possible
that it no longer works with some GPS's.

dgps station information:

The differential radio may be tuned to one of two differential sources:
	
PIGEON POINT, CA 
Status:                     Operational
RBn Antenna Location:       37,11.2N;122, 23.4W 
REFSTA Ant Location (A):    37,11.22469N;122, 23.39607W 
REFSTA Ant Location (B):    37, 11.20933N;122, 23.38592W 
REFSTA RTCM SC-104 ID (A):  266
REFSTA RTCM SC-104 ID (B):  267
REFSTA FIRMWARE VERSION:    RC00-1C19
Broadcast Site ID:          883
Transmission Frequency:     287 KHZ
Transmission Rate:          100 BPS 
Signal Strength:            75uV at 180 NM

Distance to WSRCC 35 miles 
SNR 10 db (night)

POINT BLUNT, CA 
Status:                     Operational
RBn Antenna Location:       37,51.1899N;122, 25.1439W 
REFSTA Ant Location (A):    37,51.1829N;122, 25.13582W 
REFSTA Ant Location (B):    37, 51.19319N;122, 25.16276W 
REFSTA RTCM SC-104 ID (A):  268
REFSTA RTCM SC-104 ID (B):  269
REFSTA FIRMWARE VERSION:    RC00-1C19
Broadcast Site ID:          884
Transmission Frequency:     310 KHZ
Transmission Rate:          200 BPS 
Signal Strength:            100uV at 60 NM

Distance to WSRCC 33 miles 
SNR 30 db (night)

see: the following URL for the official status.
http://www.navcen.uscg.mil/ADO/DgpsLatestStatusComplete.asp
http://www.nis-mirror.com/ADO/DgpsLatestStatusComplete.asp

GPS data Cable:

The program assumes use of a reasonable cable with the modem control
lines looped back correctly.  If you already use your computer to
transfer data to/from your gps, chances are that your cable is good
enough.

The GPS radio:

The GPS radio is a Garmin DBR-21 with firmware verison 2.0 .  The
antenna is a 4ft "Loran/DGPS" fiberglass whip mounted on my roof with
the antenna base approx. 15 ft above the ground level.

Port number change:

The first releases of this client used a different port number which
was a word play off of the official name of the protocol RTCM-SC104.
Unfortunately that port had been officially assigned to something else
already.  IANA has kindly assigned us the port 2101 for both TCP and
UDP.  Thank you IANA!

If you had installed previous versions of this software with the old
port number, please update your /etc/services file.

BUGS:      dgpsip-bugs@wsrcc.com
GENERAL:   dgpsip@wsrcc.com

Apologies in advance if you get bounces for an overly enthusiastic
spamfilter guarding my personal mailbox.  The above addresses are much
less filtered.

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