Since 1999 PocketSat has been the leader in satellite tracking for handheld devices.
Though all members of the PocketSat family have always used the full industry standard SGP4 and SDP4 orbit propagation algorithms, the search strategies used by the original PocketSat allowed even the humble Palm Pilot to calculate when satellites would be visible at a location on the ground (calculating "passes") in a matter of seconds, rather than minutes. This allowed satellite observers and amateur radio operators the ability to find passes "on the fly" and freed them from having to prepare calculations ahead of time and print them out. In addition, a real-time graphical plot of satellite positions in the sky made locating them simpler.
With the advent of more powerful handheld devices with high resolution color screens, a new application: PocketSat+, was developed. PocketSat+ extended PocketSat from being simply a "pass calculator" into a full-fledged satellite tracking suite, allowing realtime tracking of multiple satellites at a time, displaying their position on a map of the Earth or a view of the sky.
Now, with the new crop of powerful smartphones, comes a new version: PocketSat3. Building onto PocketSat+, PocketSat3 has a new user interface designed for "finger operated" devices. It also adds the ability to track literally thousands of satellites simultaneously, as well as the being able update satellite data directly over the Internet and to make use of built-in GPS capabilities to determine an observers location on the Earth.