engleski

RTK GNSS for UAVs and Aerial Photography

Development of Unmanned Aerial Vehicles (UAVs) in recent years opened a new field of aerial photography and filmmaking because it made possible for amateurs to capture photos and videos from air without the need for very expensive equipment or renting pilots and aircrafts. Depending on a budget and requirements, there is a lot of UAVs allowing 4K video recording and high resolution imaging. For special tasks, it is required that more than one UAV flies over some area. Precise guidance is not possible when using standard precision GNSS receiver and the solution for this problem is in systems which use Real Time Kinematic (RTK) upgrade. RTK is based on correlating L1 carrier instead of C/A or P codes, which gives a huge increase in accuracy of distance measurement. By correlation of the carrier it is possible to achieve accuracy of up to one centimetre. With the reduction in price and size of RTK systems, it became possible to purchase these systems for under $1000, which made them affordable and possible to integrate in smaller and cheaper UAVs. Currently it is possible to purchase couple of RTK implementations for UAVs which use either closed or opened communication protocols for integration with flight controllers. The largest UAV manufacturer, DJI, offers a solution which provides horizontal accuracy of 1 cm and vertical accuracy of 2 cm with a closed communication protocol and possibility to use only with DJI flight controllers, without the possibility to extract position information, except for precise navigation. This system has a much higher price tag and therefore it is being less used by amateurs. Among open platforms, the most popular are Here+ from HEX and Reach from Emlid. Here+ uses u-blox M8P chipset and provides horizontal accuracy of 2.5 cm, which should be enough for precise aerial mapping and creating flight plans with couple of UAVs in rather close formation. Reach M+ system advertises horizontal accuracy of 0.7 cm, but is not being tested yet, while it will be available in June 2018. Two latter platforms allow extraction of position information and geotagging, which makes them suitable for aerial photography and mapping with high accuracy and without the need for specific proprietary equipment.

UAVs ; RTK ; Geotagging

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