The best replacement for ads-b is radar.

The best alternatives to ads-b are rated as following:
★★★★★  radar
★★★★  mode s
★★★★  tcas
★★★  ads-c
★★★  acars
★★  xm weather
★  xm

Your alternative for ads-b is not listed? Suggest!
Speaking about ads-b, one probably shouldn't forget about foreflight.

Other search terms related to ads-b and their ratings are:
★★★★★ foreflight
You have in mind a companion for ads-b and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of ads-b in all years. Click on graph for more.
ads-b
radar
mode s