GPS Huddle help

How GPS Huddle works

Open GPS Huddle on two or more phones and lay them on top of each other. Each phone sends its GPS position to our server. The server averages the positions that were measured in the last few seconds within 25 metres of each other, and every phone shows that average and how many phones it is based on.

How much more accurate does it get?

A bit, but less than you might hope.

Every GPS position has two kinds of error:

• The phone's own error. Each receiver adds its own noise. This part differs from phone to phone, so averaging several phones cancels part of it out.
• The shared error. Phones lying in the same spot see the same satellites, through the same atmosphere, with the same signals bouncing off the same buildings. All of them are wrong in roughly the same direction, and averaging cannot remove that.

So three phones are not three times, or even √3 times, as accurate as one. How much you gain depends on how much of the error is each phone's own.

Getting the best result

• Mix brands and models. Different GPS chips make different mistakes, so they cancel each other out better than three identical phones do.
• Find an open sky. Buildings, trees and car roofs block and reflect satellite signals. Open ground beats a street between tall buildings.
• Wait a moment. A phone's position settles in the first seconds or minutes after you open the app.
• Keep the phones still, stacked or side by side.

Coordinates

Tap the coordinates to switch between decimal degrees, degrees with decimal minutes, and degrees, minutes and seconds. Touch and hold them to copy.

Your location

GPS Huddle sends your position to our server only while the app is open, and only to average it with the phones around you. Those phones, within 25 metres of you, see your position on their map, but not who you are. The server keeps only your latest position and deletes it about a minute after your last report.