Topodrone PPK Upgrade Kits are independent devices for professional drones that include the on-board multi-system L1/L2 GNSS receiver Topodrone PPK with built-in IMU for performing aerial survey with an 2-3 cm XYZ accuracy without using GCPs. Installation of Upgrade Kits can be performed by yourself, and it takes no more than 15-20 minutes. Topodrone PPK Upgrade Kits allow you to modify your drone and use it to create 1:500 topographic maps, accurate measurement of volumes, engineering and other surveys.