How Far Can A GPS Tracker Work?

Is there any distance limit of a gps tracker?

A short answer? No distance limit under good gps signal.
Longer answer? It depends on your software, hardware and signal. But the rule of thumb is that a real-time GPS tracking device with perfect line-of-sight cellular coverage can be accurate to 6 feet and will work anywhere cellular coverage exists.

Remember the trilateral measurements? There are many factors that can affect the accuracy of each circle (or sphere, really), each of which affects that intersection point.

For example, hilly or otherwise variable terrain can interfere with the satellite's line of sight, so to speak, and hinder the accuracy of the readings, as can dense forests. Similarly, if you only have three satellites available to you instead of four, you will no longer be able to choose which three to use in a trilateral survey, which can also affect accuracy.
Likewise, some models of GPS trackers are better than others. This depends on the software and hardware used, as well as how often the information transmits GPS location information between the device and the satellites it relies on.