Global Positioning System
The Global Positioning System (GPS) is a satellite navigation system.
There are several places where GPS information can found. It can be very useful for forensic investigations in certain situations. GPS devices have expanded their capabilites and features as the technology has improved. Some of the most popular GPS devices today are made by TomTom. Some of the other GPS manufacturors include Garmin and Magellan.
TomTom provides a wide range of devices for biking, hiking, and car navigation. Depending on the capabilities of the model, several different types of digital evidence can be located on these devices. For instance, the TomTom 910 is basically a 20GB external harddrive. This model can be docked with a personal computer via a USB cable or through the use of Bluetooth technology. The listed features include the ability to store pictures, play MP3 music files, and connect to certain cell phones via bluetooth technology. Data commonly found on cell phones could easily be found on the TomTom910. Via the Bluetooth, the TomTom can transfer the entire contact list from your phone. The GPS unit also records your call logs and SMS messages. Research needs to be done to see if the TomTom stores actual trips conducted with the unit. This would include routes, times, and travel speeds.
The TomTom unit connects to a computer via a USB base station. An examiner should be able forensics acquire the harddrive through a USB write blocker. If not, it may be necessary to remove the hard drive from the unit.
Digital Camera Images with GPS Information
Some recent digital cameras have built-in GPS receivers (or external modules you can connect to the camera). This makes it possible for the camera to record where extactly an photo was taken. This positioning information (latitude, longitude) can be stored in the Exif metadata header of JPEG files. Tools such as jhead can display the GPS information in the Exif headers.
Cell Phones with GPS
Some recent cell phones (e.g. a Motorola EZX phone such as the Motorola A780) have a built-in GPS receiver and navigation software. This software might record the paths travelled (and the date/time), which can be very useful in forensic investigations.