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SMSH - SMS Handler for GPSS

Updated 1000 Tuesday 13th October 2009

Robin Hi ! I've set up this page for those helping me test SMSH - the SMS Handler for GPSS. Please look at the SMS page - if you have not already. This deals with the more basic questions such as if you should be using SMS for your GPSS application, or should you write your own software.

I am very grateful to those who have helped me make such rapid progress with such a few hours of my time. In particular I would like to thank my old friend Klaus Hirschelmann, already mentioned on the RADIO page, who provided me the VB code to implement PDU conversion. Thankyou everyone who have provided me information or assisted in the testing.

What does SMSH do ?

SMSH runs on the same PC as GPSS and handles the GSM modem, or mobile 'phone being used as a modem, connected to the PC COM port. Incoming SMS Position Reports are translated into a standard format and injected into GPSS through the software interface.

SMSH is being used to test a wide variety of SMS products and systems - hence the large number of controls - but don't be frightened by this :-)

In the picture below, a Thuraya satellite phone has sent a GPS Position Report via SMS.


The picture shows SMSH in the foreground, being tested with GPSS in the background. SMSH would normally be run in the background, behind GPSS. The SMSH controls permit testing with various GSM modems and sources of SMS position reports.

How would SMSH be used ?

Normally SMSH would be run, the START key clicked, then minimised. GPSS is then run and will automatically receive SMS Positions with SMSH hidden.

Before this is done the required parameters must be set up, such as COM Port (1 here) and baud rate (4800 here, or more typically 19200), and SAVE CFG clicked to ensure these values appear next time SMSH is run.

Other controls support testing of SMSH with different combinations of hardware being used as a modem on the PC, and sending Position reports.

What are the SMSH Controls ?

The controls from the top are:

Where are we now ?

SMSH was only started on Friday 1st November 2002. We started with using "text mode" in the GSM AT+ commands. This meant not all mobile 'phones could be used as modems, since even those with modems may not support text mode - but need "PDU mode" (Protocol Data Units).

Version 1a of SMSH (Friday 1st Nov 2002) implemented Position Reports from:

Version 1b (Sunday 3rd Nov) implements PDU mode - thanks to Klaus H :-)
Version 1c (Tuesday 5th) implements Benefon !LOC and !EMG messages.
Version 1d (Thursday 7th) supports GK coded messages - thanks to Klaus :-)
Version 1e (Sunday 10th) supports getting GK 'phone position back from local cell.
Version 1f (Tues 3 Dec) supports scanning GSM modem memory.
Version 1g (Wed 4 Dec) supports SEND but only in text mode (not PDU).
Version 1h (Wed 11 Dec) longitude bug fix for GPSService Pilot. Allow change to AT+CMGR=

Version 1i (Thu 9 Jan 2003) supports MV SEND polling, MTX02W. Iridium 9505 ISU (thanks to Boeing).
Version 1j (Fri 17 Oct) supports Garmin Navtalk (thanks to Lindsey).

Version 1k (Sat 27 Feb 2004) TXT2PDU for Test. Supports product for Armando.
Version 1L (2nd March) fix SEND bug for TXT mode. PDU mode SEND still not available.
Versions 1m to 1q (2007) in collaboration with Gregory on Partners page. iTrack units.
Version 1r (12 October 2009) support for Globalsat TR-101 trackers added.

General Hints on Testing

Draft "Open" SMSH SMS Format

Many engineers putting together SMS solutions for GPS based tracking have tended to "do their own thing" and invent their own message format. Some formats are suitable for phone-to-phone tracking without a PC, with the user simply looking at the message on his phone display. Others are used to pass the SMS into a PC application like GPSS for map display. Many of these formats are already in SMSH.

Here is a draft "open" format that some of you may wish to adopt. After feedback and implementation, we will support it in SMSH.

It attempts to be suitable for both types of use above. It should be simple to implement because the GPS will be passing very similar data into the SMS/GPS product, such as the $GPRMC NMEA message:


Here is a minimum implementation, with lat/lon only:
i.e. the $GPRMC lat/lon but without commas: the GPSS 15 character format.

Here is an implementation with direction and speed added:
070 at 30 nmph
i.e. followed by heading (degrees clockwise from true north) then speed in knots. Some discussion may be need on whether would be better to have speed in km or mph, and or introduce additional text such as the "at". e.g. 30 nmph.

Here is the message but with an internal gazeteer (or landmarks) based on data such as GPSS GTX files, giving the 'phone user more information.
M3J3 n Bagshot

Or ...
230 at 33 kmph
M3 J3 n Bagshot

Or ...
230 at 33 kmph
43km sw London
540m ne M3 J3

i.e. 43 kilometres south west of London and 540 metres north east of M3 Junction 3.
- as in GPSS WAW logic.