AVL stands for Automatic Vehicle Location, which is accomplished by means of a tracking GPS and M2M modules. Actually a small AVL can be used to track any objects, including kids and pets.

The OpenAVL project should be able to communicate with the tracking web server or any web server via SMS and IP/GPRS.

Required features are:

# The 3rd generation highly precise GPS module. SiRF-III is preferred, MediaTek GPS is also all right.
# AVL sends latitude, longitude, altitude, course, velocity, heading, UTC time and satellites in view to any mobile phone, optional web site and email account.
# Smarter power saving algorithm for M2M/GPS modules and long enough battery life.
# Over-the-air Configuration via text message commands from mobile phone and optional web.
# Password security and unique identifier.
# Manual locate and automatic tracking modes via text message.
# Automatic tracking mode depends on the velocity.
# Alerts when speed limit is exceeded.
# Reports of mobile phone battery and signal status.
# Retains tracking messages if out of GSM coverage, and sends when back in coverage.
# Retains and reports last good fix if it loses GPS coverage. (Optional)
# Reports of mobile phone Cell ID in case GPS is out of coverage, i.e. in a building. (Optional)
# Watchdog timer prevents device lockup.
# AVL should support GSM-SMS, and optionally support GSM-CSD and GPRS depending on device configuration.

Link: OpenAVL - part one
OpenAVL - part two