GPS and Navigation Apps

I’m having the problem with GPS and my navigation apps. I am using ipad pro 5th generation and all is updated. The gps works for some time (with Navionics and Aqua map) but then loses signal or goes to sleep as it seems. It starts working again if I move the iPad a little. I had allowed access to location while using the app and changed it to always allow but still have the prob. We also connected the Bad Elf GPS but continue to have the same problem. Any ideas? This worked fine before hurricane season this year. We have been off the boat since July and just stared using it again. I saw other posts about this earlier in the year but did not see a fix.