A camera drone is several hard problems in one airframe. A flight controller fuses an IMU, barometer and GNSS to hold the aircraft steady; ESCs and brushless motors turn the props; a gimbal stabilises the camera on three axes; a radio link carries control up and HD video back; and vision sensors watch for obstacles. The reference design is the flight stack, the gimbal and the transmission system together, and that is exactly the stack one company owns end to end.
That company is DJI, in Nanshan, which holds something like three-quarters of the world's consumer drone market and makes its own flight controllers, gimbals, transmission, propulsion and sensors. It is the most complete vertical integration in this atlas, and it casts the longest shadow. The honest way to read the rest of the field is by where DJI is not dominant, because head-on it is very hard to beat. Autel, also Shenzhen and founded by former DJI engineers, is the one credible consumer challenger.
Independent design clusters in the gaps. FPV racing and freestyle is a parts culture, frames, flight controllers, motors, cameras and video transmitters mixed and tuned by small specialist houses rather than bought as a sealed unit. Agriculture is the field China leads outright: spray-and-seed platforms covering hectares a flight, a duopoly of DJI Agras and Guangzhou's XAG over a deep ODM base. And there is enterprise survey and inspection, plus the toy-quadcopter floor out of Shenzhen and the Chenghai cluster in Shantou.
For export the gates are FCC and CE for the radio plus, increasingly, Remote ID and flight-zone rules that vary by country; weight class decides much of the regulation. Above this layer sits DJI, and beside it Autel, XAG and EHang's passenger craft. The houses below win on a niche, FPV, agriculture, survey, price, rather than by out-integrating Shenzhen's giant. The category where the apex and the challengers all share one city.