I have a GPS Tracker which sends the GPRMC string of the NMEA 0183 protocol, at fixed periodicity, to a predefined number as SMS. I am looking for a software which can port these incoming SMS to a COM port to plot them dynamically to Google Earth or a custom GIS application, and use the name of the sending GPS as a label on the map. THe software should be capable of simultaneously tracking multiple GPS trackers simultaneously.
Kannel is the most known sms gateway (Free and Open Source), it runs both in Linux and Windows. You can connect it with a GSM modem or a mobile phone to send or receive sms (or MMS). If you have a GPS who can connect to GSM you have the solution. AND of course it connected with Mysql or Postgresql and more DB. From a database you can send the data to a web system.
Would Gammu SMS Daemon http://wammu.eu/smsd/ be a start?
Gammu SMS Daemon is a program that periodically scans GSM modem for received messages, stores them in defined storage and also sends messages enqueued in this storage. It is perfect tool for managing big amounts of received or sent messages and automatically process them.
You can currently store received messages in files or in various databases. MySQL and PostgreSQL are supported natively and wide range of others (including SQLite) through libdbi (libdbi backend is currently not available in Windows builds).
Check out SlingshotSMS. It's a minimal SMS server which connects GSM modems to websites and applications via a simple HTTP interface. Here's a sample architecture.
You could do away with the Drupal backend and write your own. It's also portable so you can run it from a flash drive.
THe software should be capable of simultaneously tracking multiple GPS trackers simultaneously.
If I understand it correctly, those would be different numbers sending to your tracker? If so, you could just filter them by sender so you would be able to distinguish them.