From 91057be677dfa64b3f89abf363737f3445c791d7 Mon Sep 17 00:00:00 2001 From: Philip Sargent Date: Tue, 5 May 2026 15:14:25 +0100 Subject: [PATCH] sbas moved - online edit of handbook/survey/gps.htm --- handbook/survey/gps.htm | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/handbook/survey/gps.htm b/handbook/survey/gps.htm index 49bba56e5..af20823e3 100644 --- a/handbook/survey/gps.htm +++ b/handbook/survey/gps.htm @@ -66,9 +66,6 @@ of the entrance.

Also sketch the entrance in comparison to other holes close by - in the notebook, which you have with you, and always bring 2 pencils. -

SBAS

-Check whether your phone is using SBAS "Satellite-based Augmentation Services", which is another name for EGNOS, the differential GPS system. -You need to record if SBAS is in operation whenever you record the position of a cave entrance (and ideally whenever you take a photo too, but that would be unrealistic). A screenshot of the GPStest screen does this for you.

Differential GPS (SBAS) has existed since 2018, but it is often not actually available on a phone. The number of satellites now renders previous advice obsolete (e.g. Wookey's 1996 article). @@ -129,6 +126,10 @@ on coordinate systems has been moved to a different page. If you are really

Unfortunately RTPPP has not actually caught on [2026] and it is still only available for experts and phones supporting L2 and L5 frequencies have been slower to appear than we hoped. Read Wikipedia on Real-time kinematic positioning (RTK). +

SBAS

+We used to be very concerned whether we were using SBAS "Satellite-based Augmentation Services" or not. (This is another name for EGNOS, the differential GPS system.) A screenshot of the GPStest screen does this for you so you don't need to worry about this. + +
Next survey guide page - 'Base Camp: getting it in to the computer'