Why GPS takes a few minutes to settle at the start of a hike

The short answer

A GPS receiver does not know its position the instant it is switched on. It first has to find enough satellites, work out roughly where they are in the sky, and combine several of their signals before it can compute a position at all. Until that process finishes, whatever position it reports is either missing, based on an old estimate, or built from fewer signals than it would normally use — all three read as "less accurate" on a map. That first stretch of settling-in time is completely normal, and it is over quickly on every walk.

This is a different issue from a canopy or a canyon weakening an established signal. It has nothing to do with where you are standing. It is simply the receiver at the very start of the process everyone's phone has to go through before it can report a position at all.

Why the very first fix is slower than every one after it

A cold start

If a phone has not used GPS recently, or has travelled a long way since it last did, the receiver has to work everything out close to from scratch: which satellites are overhead right now, and precisely where each one sits in its orbit. That takes longer than any single fix once the receiver already knows roughly what to expect, and it can stretch to a minute or more in the worst case.

A warm start

If the receiver already has a recent, nearby estimate to build on — because the phone used location a short while ago in roughly the same place — it can lock on within a few seconds. This is the far more common case for a hike that starts near where you last used your phone, which is most hikes.

What that looks like on the recorded track

While the receiver is still settling, a recording app has little choice but to write down whatever position it is handed, because a track has to start somewhere. The result, once you look back at it, is often a rough or slightly displaced first point or two, followed by a visible jump once a proper fix arrives — a short spike or a stray leg on the line that has nothing to do with where your feet actually were. After that jump, the rest of the recording looks completely ordinary.

Starting the recording indoors, in a car, or under a roof makes this worse rather than better. Walls, a car roof and glass all block and reflect the sky in much the same way a dense canopy does, so the receiver can be starting cold from a genuinely poor view of the satellites, not just from having been idle for a while.

Why waiting a few seconds at the trailhead is not superstition

Standing still in the open for a few seconds before you set off gives the receiver a clean, unhurried settling-in period rather than baking a rough early position into a route you cannot go back and fix. This is exactly why a recording app that pauses to wait for a signal before it starts the clock is not being slow for no reason — it is letting the messy part happen before anything gets written down, rather than after.

None of this requires watching the screen. A position either has enough satellite signal behind it or it does not, and nothing you do on screen changes what the sky is providing at that moment.

What does not help

• Restarting the app or the recording. This throws away whatever settling-in the receiver had already done and can start the whole process over, from further back rather than closer to a fix.
• Walking faster to "shake off" a bad first point. The stray point is already written into the track; moving does not undo it.
• Checking the screen repeatedly. It changes nothing about the sky above you, which is the only thing that determines how quickly a fix arrives.
• Comparing the first few seconds of two different apps' recordings of the same start. Whichever one happened to have a warmer start that day will look better in that narrow window, for reasons that have nothing to do with either app being more accurate in general.

What to expect and what to ignore

A rough first few seconds is worth recognising for what it is and then ignoring. It very rarely affects the distance or elevation gain for a route of any real length, because it is a handful of points out of many hundreds or thousands. Where it is worth a second look is right at the start of a short route, where a stray point makes up a larger share of the total and can nudge the opening distance or the very first elevation reading slightly off.

TrailCam waits for a signal after you pick what you are doing, rather than starting the clock the instant you tap the button, and it keeps recording in the background with the screen off or while you are in another app once it does start. Routes export as GPX 1.1 or CSV, single or as your whole history, as part of the optional Pro upgrade. It is free to download.