SJ-GPS is a free Android app developed by Zheng Xiang. It is a lifestyle app that allows users to control their quadcoptor with a wifi camera module. The app also displays a real-time video taken by the wifi camera module. SJ-GPS offers various features such as VGA, 720P, and 1080P resolution support, take photo and record video function, and 3D function support.

With SJ-GPS, users can enjoy a thrilling flying experience with their quadcoptor and capture amazing moments with their wifi camera. The app's interface is user-friendly, and it provides a convenient way to control the quadcoptor. The real-time video feature allows users to see what their wifi camera is capturing and adjust its position accordingly. SJ-GPS is a must-try app for quadcoptor enthusiasts and anyone who likes to capture aerial footage.