Two. The 15km transmission length can only be attained underneath the FCC regular when calculated in an out of doors surroundings without the need of interference. The SRRC regular is adopted in mainland China, plus the furthest transmission length is 8 km. Mavic 3M with RTK module for centimeter-amount positioning. https://m3mhomes.com/residential/m3m-skywalk-sector-74-gurgaon/