GPS information shipped with Psi-Mapper/London for Psion Series 5
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In case you're not sure what a GPS is, it's a small unit with a built-in
aerial which receives positioning information from the american GPS
satellite system (see picture) to tell you your current latitude,
longitude, velocity, altitude etc.

Of course, if all this seems like whimsical gadgetry to you, you're
probably right, but then I like gadgets!

Note that ETA etc are calculated using your set average speed in your
personal preferences. I've tried using actual speed from the GPS etc, but
so far the results are just as transient and and/or approximate as using a
set average ...

So what do you need if you want to try all this out?

   * Psion Series 5 palmtop computer with 200k of free system memory
   * Installation of appropriate latest version of Psi-Mapper/London
   * The 'PsiWin' serial cable plus the data cable for your GPS and a
     9-pin male-to-male 'null-modem' adapter
   * GPS receiver with NMEA 0183 v1.5 or higher interface (one of the
     Garmin units is ideal)

Also worth thinking about is integrating power leads for your Psion and
GPS into the wiring if you intend to run them both for long periods! Note
that the Psion doesn't *have* to be on all the time, you can just turn on
when you need a 'fix'!

Acquiring the above
-------------------
I'll assume you already have a Psion Series 5 and a serial cable of some
kind, or you probably wouldn't have got this far! First item on your
shopping list is to buy a GPS. Any of the Garmin units will work fine.
In theory, other makes should also work, but not all manufacturers
implement the NMEA standard properly, so watch out!

Next get the manufacturers data cable for your GPS. This will usually come
either with bare wires on the end or with a 9-pin PC serial connector.

The PsiWin cable ends in a 9-pin serial connector, which will look
similar to the data cable connector supplied by the GPS manufacturer.
The trick on connecting the two together is to make sure that the
Receive and Transmit lines are swapped over. You can either make up a
Male-to-Male adapter yourself, swapping pins 2 and 3, or you can try
buying one ready made-up from a computer shop. Ask for a 9-pin M-to-M
null modem adapter.

Getting the GPS link working
----------------------------
Assuming you now have all the bits you need:

  1. Plug everything in
  2. Start up the GPS and position in your car to get good satellite
     reception. I find it works very well wedged on top of the dashboard,
     but if you have a heated windscreen this may be a problem for you, as
     the mesh of wires can block the signal.
  3. Start up Psi-Mapper and go to the map you want the moving map icon
     displayed on-top of, and set your required sticky displays/options.
     If you're wanting to try out the ETA/Distance left option, choose
     your settings in the 'Moving Map Settings' dialog, and 'select' a
     departure and destination (place or overlay item) by 'find'ing them
     in the usual way. When all is ready, select 'GPS Moving Map' from
     the right-hand menu.
  4. If all is well, you'll see one of two icons on your map. Either a
     cross-hair showing current position or a 'Poor GPS' icon. The latter
     will appear whenever your GPS's output quality deteriorates to warn
     you that it doesn't really know where it is anymore. Try waiting or
     re-positioning your GPS ....
  5. If the cross-hairs get too close to the edge of the screen, the map
     will re-centre itself and stay in 'GPS Moving map' mode.

Have fun!

Extra notes
-----------
   * If you should blow anything up or injure yourself in any way, please
     note that I take no responsibilty whatsoever for use of this software
     product! And if you're driving, keep your eyes on the road! I mean it!
     ONLY USE THIS PROGRAM ON THE MOVE WHEN SOMEONE ELSE IS DRIVING. IF YOU
     *DO* USE THIS ALONE ON THE MOVE, I WILL NOT BE HELD RESPONSIBLE WHEN
     YOU CRASH HEAD-ON INTO A JUGGERNAUT!!!
   * Technical one, this. Your GPS map datum should be set to WGS 84, if
     it's not already! Also, the NMEA version supported by Psi-Mapper is
     0183 version 1.5. Psi-Mapper normally gets its information from the
     NMEA sentence $GPRMC, so if your GPS doesn't output this word you're
     last hope is to go into the moving map settings dialog and select
     'Magellan (Position only)', which tells Psi-Mapper to go for the
     lowest common denominator and use $GPGLL instead, although this only
     gives position and not velocity or heading. Worth a try though, if
     you're having problems!

     See also my guide on troubleshooting GPS operations, below.

Places to try in your quest for GPS units and other hardware:
-------------------------------------------------------------
   * Positioning Ltd on 01403 271114
   * Pumpkin Marine on 0171 4806630
   * Garmin UK on 01794 519944
   * Maritek on 0141 5542492

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                       Troubleshooting GPS operations

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So, you've been trying out Psi-Mapper on your Psion with your new GPS
gadget. And it doesn't seem to work, either at all or terribly reliably ...
Well, you're in the minority, because there are lots of people out there
using it all quite happily together, but I accept that what with all the
things that could go wrong, a few brief notes might be in order!
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Things to think about and look out for:

   * Are you using the latest version of Psi-Mapper? If not, why not?

   * Is your GPS 100% compatible with NMEA 0183 v1.5 and above? Psi-Mapper
     needs the $GPRMC word output every 2 seconds or more frequent. The
     best way to check what your GPS is outputting is to install the
     'Comms' app on your Psion (you'll find it on the 'C' drive on a 3a),
     set the parameters to 4800 baud, 8 bits, no parity, no handshaking,
     and see what appears on your screen. You may find it useful to
     capture some of this output to a text file for later analysis, or
     for sending in for diagnostic purposes.

     Garmin GPSes seem to meet these criteria very easily, other makes
     tend to be more non-standard. In particular, the Magellan GPSes only
     output sub-sets of the NMEA standard data sets. If you've got a
     Magellan, set it to NMEA mode 'B' and make sure you're using v3.9 of
     greater of Psi-Mapper/GB, as I've been tweaking the code to work more
     reliably on the Magellan's cut-down NMEA signals.

     If you don't think you can get your GPS to output the $GPRMC word at
     all, but it *can* do $GPGLL, then go into the moving map settings
     dialog and select 'Magellan (Position only)', which is better than
     nothing!

   * How are you linking the two together? Are you 100% sure the pins/wires
     in your connections aren't shorting or dropping out? Are all the
     cables pressed fully home? Using the pin-outs given in the GPS and
     3-Link manuals, try 'buzzing out' the cables you're using to ensure
     that the signals are going where you think they are!

   * Make sure your GPS's output is in the right NMEA mode. For example,
     the Garmin defaults to using its own proprietary GARMIN/GARMIN mode,
     and you need to change it to NMEA/NMEA ...

If you've addressed the above and are still having problems, please e-mail
me!

Steve Litchfield
slitchfield@cix.co.uk
