To conform to Federal Communications Commission guidelines, cell phone companies must be in a position to provide authorities with cell phone latitude and longitude to an accuracy of 50 to 300 meters. Cell Tower Triangulation doesn’t always satisfy this requirement. By way of comparison, commercially accessible GPS modules will be able to get precision down to less than 10 meters. This relies on many factors, as GPS signals are often quite weak and they are disturbed by many environmental factors. With Mobile Location Services (MLS), the GSM cellular network provider utilizes triangulation techniques to determine the position of the device, its accuracy is proven to be much worse than that of GPS. MLS is also affected by factors similar to GPS in the sense of the barriers affecting signal quality and the density of GSM towers to assist in the triangulation effort. In rural areas position accuracy may be off as much as a mile. GPS receivers, whether or not inside a mobile phone, or a dedicated Portable gps tracking system, determine position through process of accurately timing the signals passed on by GPS satellites. This data includes the time the message was sent, highly accurate orbital details (formally referenced as the ephemeris), along with the overall system state and believed orbits of all GPS satellites (technically referenced as the almanac). GPS receivers often take a long time to become ready to navigate after being turned on because it must acquire some basic information in addition to capturing GPS satellite signals. This slow start can be caused if the GPS smartphone has been turned off for days or weeks, or has been transported a significant distance while turned off. The GPS must update its almanac and ephemeris data and store it in memory. The GPS almanac is a set of data that every GPS satellite transmits. When a GPS receiver has current almanac data in memory, it can capture signals and compute initial location faster.