A satellite tracking turntable is a high-precision rotating platform capable of automatically aligning with and continuously tracking artificial satellites moving in space. It typically consists of two main parts: the turntable's mechanical structure and the tracking control system.

Main components

1. Mechanical turntable

Structural form: Usually azimuth-pitch type, meaning it can rotate freely in the horizontal direction (azimuth angle) and the vertical direction (pitch angle). Some special designs also adopt XY axes or other forms.

Drive system: High-precision motors (such as servo motors or stepper motors) and reducers are used to drive the turntable to move smoothly and accurately.

Supporting equipment: Various devices are mounted on the turntable, the most common of which is a satellite communication antenna (parabolic antenna), but it can also be an optical telescope, laser rangefinder, radar or electronic intelligence gathering equipment, etc.

2. Tracking control system

Core controller: A computer or dedicated processor that is the "brain" of the turntable.

Tracking algorithm:

Program tracking: This is the most commonly used method. Based on the known satellite orbital parameters (TLE data), combined with the turntable's precise geographical location and time, the controller calculates the satellite's azimuth and pitch angles in real time, and then drives the turntable to point to that position.

Automatic tracking: Primarily used in satellite communications. The antenna detects the strength of the received satellite signal (such as a beacon signal). If the signal weakens, the system drives a turntable to perform a small-range scan to find the point with the strongest signal, thus maintaining optimal alignment at all times. Common techniques include step tracking and conical scanning.

Sensors: These include high-precision encoders that provide feedback on the actual angular position of the turntable, forming a closed-loop control to ensure pointing accuracy. A GPS receiver will also be integrated to obtain precise time and location information.

Main application scenarios

Satellite tracking turntables are key equipment in satellite application ground systems and are widely used in:

1. Satellite communication

Mobile communication: Installed on vehicles, ships, and aircraft, it maintains a constant connection with communication satellites while in motion, enabling uninterrupted internet, telephone, and video transmission.

Immobile communication: Used for emergency communications, news broadcasting vehicles, etc., requiring rapid deployment and alignment with satellites. 

VSAT station: Some VSAT terminals that need to track multiple satellites or low orbit satellites also use tracking turntables.

2. Space Science and Exploration

Satellite laser ranging: This involves emitting laser pulses towards a satellite and receiving its reflected light to accurately measure the distance between the Earth and the satellite. It is used to determine the Earth's gravitational field and monitor crustal movement. This requires the turntable to have extremely high pointing accuracy and tracking speed.

Optical observation: used to observe and photograph passing satellites for cataloging, morphological identification, or scientific research.

3. Military and National Defense

Electronic reconnaissance: intercepting and analyzing signals from enemy satellites to obtain intelligence.

Radar tracking: Using radar to monitor and image specific satellites.

4. Space telemetry and control

In the early stages of rocket launch and satellite orbit insertion, the large antennas of the ground control station need to precisely track the rocket and satellite in order to measure the orbit, send commands, and receive telemetry data.

5. Data relay

This is used to track relay satellites (such as China's "Tianlian" series). These satellites are also in motion, and ground stations need to track them to receive data relayed from other spacecraft (such as spacecraft, space stations, and low orbit satellites).