iOS and/or Android Apps - Need to improve a Google Maps feature that shows multiple markers on a map

Hi. I already store the users' locations in my mysql db (latitude and longitude) and we update them frequently (like every 30 seconds maybe) so we know where users are in real-time. But, I also have a Business Directory page/feature that shows multiple business markers on a map. I want to try to change this to show Service Workers in real-time (that are in vehicles). So I think I can modify the API that populates the Business Directories, so it pulls the location lat and long from the users table (which frequently updates the users lat and long). But, then I'll probably need some help making sure the map refreshes the locations of the markers frequently since the lat and long change every 30 seconds or so. I may also need help tweaking a few other features that are part of this page too - like currently, the user/visitor can already click on any map marker and it pulls up a Directory Details profile page. I may need help linking the phone number and email or even a message now button (because we have direct user-to-user messaging in the site). Basically, we want to show Service Workers on a map in real-time then show the logged in user's marker (only to them), so they can see if there's anyone to help around them right now - then click on the map market to contact them.