Hi. There is no need of transmitter. You can change some parameters in mission planner and set the ADS-B to see all the planes and also avoid them automatically without requiring any actions from that ground pilots. Take a look at this user guide for setting up the ADS-b in the mission planner and this guide also helps for the parameter settings :- Link : - ADS-B IN Carrier Board - CubePilot
You can directly see all the planes approaching in the q ground control maps. You will see a icon actually on the q ground control maps and also you can see in the mission planner map. No need of any other transmitter. Hope it helps. 
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