"Many satellites and spacecraft require accurate timing signals to ensure the proper operation of scientific operation. In the case of GPS satellites, accurate timing is essential, otherwise anything relying on GPS signals to navigate could be misdirected. The third technology demonstration planned by NASA's Jet Propulsion Laboratory is the Deep Space Atomic Clock. The DSAC team plans to develop a small, low-mass atomic clock based on mercury-ion trap technology and demonstrate it in space"
~Slashdot at Tech News.

Will TSO Mobile and its GPS tracking services be affected by this test? Definitely not. As the title says, this is only a test and the technology of an atomic clock would not be implemented if it does not work as expected. Will it work as expected? Most likely yes! come on, it is NASA!