Here is the CMT Uptime check phrase
PUBLICATIONS

Comparing the Data Quality of Global Positioning System Devices and Mobile Phones for Assessing Relationships Between Place, Mobility, and Health: Field Study

Clarke, Philippa J; Gomez-Lopez, Iris; Veinot, Tiffany C.E.; Goodspeed, Robert; Yan, Xiang; Hardy, Jean; Vydiswaran, VG V; Berrocal, Veronica J; Romero, Daniel M. (2018). Comparing the Data Quality of Global Positioning System Devices and Mobile Phones for Assessing Relationships Between Place, Mobility, and Health: Field Study. JMIR Mhealth Uhealth. 6(8), e168.