The Drone Used to Measure the Tianlai Dish Antenna Gain Patterns - - PDF document

The Drone Used to Measure the Tianlai Dish Antenna Gain Patterns

Jingxin Liu, Qiaolin Shuang, Jiexia Li, Santanu Das, Fengquan Wu, Juyong Zhang & Peter Timbie April 24, 2018

• 1. The scheme of the measurement system based on the drone

Figure 1. The measurement system based on the drone

• 2. The specifications of DJI Matric-600 Pro

We have bought a DJI Matric-600 Pro drone, Its specifications and some discussions are as follows:

1). Structure of the Drone

Figure 2. The structure of Matric-600 Pro

2). Speed and Velocity of the Drone

The ascent and descent of drone will take about 10 min when the drone flying up to 1000 m height.

3). Hovering Time of the Drone

Figure 3. Payload and Flight time

The graph shows that the transmitter is lighter, the fight time is longer. so it will be better that the maximum mass of the transmitter system is not more than 2 kg. Now it maybe can meet

• this. For the purpose of extending flight time during the measurement, we have bought 2 set of

batteries.

Figure 4. The transmitter of the measurement

4). Hovering accuracy of the drone

The hovering accuracy of the drone with P-mode is not nice, and it doesn’t meet requirement. So we will use a D-RTK GNSS to improve the hovering accuracy of the drone.

Figure 5. D-RTK GNSS system

The D-RTK GNSS system use dual antennas, and it is able to withstand strong magnetic interference and provides centimeter-level accuracy in environments with metal structures. Its specifications as follow:

GPS L1 (1575.42MHZ), GPS L1 (1228MHZ); BEIDOU B1 (1561.098 MHz), BEIDOU B2 (1207.14 MHz)

5). Remote controller of the drone

Some main specifications of the remote controller as follows:

Figure 6. The hovering point in a test of the drone

6). Flight height of the drone

The Max service ceiling above sea level of the drone that we bought is 2500 m. The drone can reach 4000 m height if it is changed another type of propellers. The far-field region of an antenna is at distances r > 2D2/ λ , where D is the size of the diffracting

• aperture. For the Tianlai dishes, with D = 6 m, the far field at 750 MHz is 180 m and at 1400

MHz it’s 630 m. For the cylinders, with D = 15 m, the far field is 1,100 m and 3,900 m,

• respectively. But in general, the max altitude for the entertainment drone must be below 500 m

in accordance with Chinese laws and regulations. We think, different from the entertainment, the drone is used for scientific experiment, so we are applying for license to lift the height restriction.