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What Is Time to First Fix (TTFF)?

TTFF is the time it takes a GPS device to find your position

By Fred Zahradnik Fred Zahradnik Freelance Contributor Pennsylvania State University Former Lifewire writer Fred Zahradnik has a long history as a writer and is considered an expert on all things related to GPS products and software. lifewire's editorial guidelines Updated on March 3, 2020 Tweet Share Email Maciej Frolow / Getty Images Tweet Share Email Connected Car Tech Navigation Android Auto Apple CarPlay Time to First Fix (TTFF) describes the time and process required for a GPS device to acquire enough satellite signals to provide accurate navigational information. The word "fix" here means "position." Various conditions can affect the TTFF, including the environment and whether the GPS device is inside or outside. GPS navigators need to be mostly free of obstructions between the device antenna and the orbital satellites. A GPS must have three sets of data before it can provide accurate position: GPS satellite signals, almanac data, and ephemeris data.

TTFF Conditions

There are usually three categories that TTFF is split up into: A "cold" or "factory" start refers to a situation in which the GPS device must acquire all data in order to start navigation, like if the device is brand new or has recently been factory reset. TTFF may take up to 12 minutes. A "warm" or "normal" start means the GPS has most of the data it needs in its memory and within a minute or less. A warm start happens when the device has been off for a day or so, but not off for so long that the data is outdated. "Hot" or "standby" is when the GPS device can get a signal quickly since it already has a valid position and correct almanac and ephemeris data. The device has normally been off for just a few hours. The TTFF in this situation is sometimes called "Time to Subsequent Fix" (TTSF).

More on TTFF

If a GPS device is new, has been turned off for a long period of time, or has been transported for a long distance since it was last turned on, it will take longer to acquire these data sets and get a Time to First Fix. This is because the GPS data is outdated and needs to download up-to-date information. GPS manufacturers use various techniques to speed up TTFF, including downloading and storing almanac and ephemeris data via a wireless network connection from the mobile operator instead of through satellites. This is called assisted GPS, or aGPS. Was this page helpful? Thanks for letting us know! Get the Latest Tech News Delivered Every Day Subscribe Tell us why! Other Not enough details Hard to understand Submit More from Lifewire Passive vs. Active GPS Antennas What to Do When Windows 11 Can't Connect to a Network What Is GPS and How Does It Work? How Assisted GPS Works in Cellphones 5G: Here's Everything That's Changing How to Fix Netflix Error Code NW-2-5 on Any Device How Are 4G and 5G Different? How to Use the Garmin Connect Course Creator Tool What Is Seek Time? (Definition of an HDD's Seek Time) How to Fix Hulu Error Code p-dev320 How to Control GPS Settings on the iPhone The 5 Best GPS Trackers for Hiking, Cars and More in 2022 How to Find a Hidden GPS Tracker on Your Car The 6 Best Golf Tech of 2022 How GPS Devices Use Trilateration How to Fix It When a Laptop Isn't Connecting to a Mobile Hotspot Newsletter Sign Up Newsletter Sign Up Newsletter Sign Up Newsletter Sign Up Newsletter Sign Up By clicking “Accept All Cookies”, you agree to the storing of cookies on your device to enhance site navigation, analyze site usage, and assist in our marketing efforts. Cookies Settings Accept All Cookies