Sign Up to our social questions and Answers Engine to ask questions, answer people’s questions, and connect with other people.
Login to our social questions & Answers Engine to ask questions answer people’s questions & connect with other people.
Lost your password? Please enter your email address. You will receive a link and will create a new password via email.
Please briefly explain why you feel this question should be reported.
Please briefly explain why you feel this answer should be reported.
Please briefly explain why you feel this user should be reported.
I am creating a BREW app that requests the user’s position.
If the phone cannot acquire the position, I would like to display an error.
How long should I wait for my callback to be called before I determine that the phone is not likely to get a GPS fix?
When a cold start is required, the receiver has to download a full set of Ephemeris data, which is broadcast from the GPS satellite over a 30 second cycle and re-transmitted every 30 seconds.
So I would say that 60-90 seconds (two or three Ephemeris cycles) would be a suitable time to wait before declaring failure.
http://www.navigadget.com/index.php/gps-knowledge/ttff-time-to-first-fix
Note that if a device requires an almanac download, the startup time can be much longer (on the order of 12.5 to 15 minutes). This is referred to as a Factory TTFF (Time to First Fix).