c/techniques•Posted byu/nate_107•about 2 months ago

Can't get RTK fix - systematic troubleshooting checklist

ok so after 3 months of struggling with my RTK setup and finally getting it dialed in, I wanted to share what I learned. mostly because I wish someone had written this when I started.

if your receiver says "float" and wont go to "fix" here's what to check, in order:

check your sky view first. sounds obvious but I spent two hours troubleshooting on a site next to a building. moved 30 feet into the open and got fix instantly. you need clear view of the sky in all directions. buildings, trees, even your truck can block enough satellites to prevent fix.

verify your NTRIP connection is actually working. just because your phone shows connected doesn't mean data is flowing. check the correction age in your receiver - if it says "none" or the age is climbing past 10 seconds, your corrections aren't coming through. restart the NTRIP client, check your credentials, try a different mount point.

make sure base and rover are on the same frequency. if you're running your own base with radio link, double check that both units are on the same channel and baud rate. I lost an entire morning because I'd accidentally changed the channel on the base during a firmware update.

check your baseline distance. NTRIP corrections degrade with distance. If you're more than 30-40km from the nearest reference station your odds of getting fix drop significantly. Some networks show the nearest station in the app - check it.

wait longer than you think. first fix of the day can take 2-5 minutes even in good conditions. I used to give up after 60 seconds and start troubleshooting. now I just set the pole down, let it track for 5 minutes, and usually it resolves itself.

last resort - restart everything. power cycle the receiver, close and reopen the app, reconnect to NTRIP. sometimes the solution is just turning it off and on again. not satisfying but it works more often than I'd like to admit.

Comments

AnnaSurveys•about 2 months ago

Great list for beginners. I'd add one more - check the satellite constellation status before you head to the field. There are times during the day when satellite geometry is poor for your area (high PDOP). Apps like GNSS Planning or Trimble GNSS Planning Online show you the best and worst windows.

Most people don't bother with this but if you're working in challenging environments it can be the difference between fix and float.

T. Weston PLS•about 2 months ago

One more thing that bites people - RTCM message types. If your caster is only broadcasting MSM4 messages and your receiver needs MSM7, you won't get fix. Most modern equipment handles this fine but older receivers can be picky about which RTCM messages they accept.

Check your caster's stream details to see what message types are being broadcast.

rwc_survey•about 2 months ago

The 'wait longer' advice is underrated. New users expect instant fix because that's what the marketing says. In reality, cold start to fix can take several minutes especially if you haven't used the receiver in a while. The almanac needs to update.

Also check for firmware updates. Manufacturers regularly push updates that improve fix performance.

nate_107•about 2 months ago

these are all great additions. honestly the PDOP planning thing is something I had no idea about until last week. would have saved me a lot of frustration on a job where I was trying to get fix during the worst satellite window of the day.