In the satellite signal acquisition and tracking, the locally reproducible ranging code plays an important role. For the newly launched Beidou-3 satellite in China, a method for implementing the B2a signal ranging code generator in FPGA is proposed. Taking the B2a ranging code of Beidou-3 satellite as the research object, the design principle of the B2a ranging code generator is explained in detail, which includes the analysis of the key modules of the Weil code and the Gold code generator. The FPGA is modularly designed to be scalable The B2a ranging code generator module, through the reserved register initialization interface, can realize the ranging code of different PRN satellites, solving the complex problem of generating arbitrary satellite number ranging codes, for the design of Beidou No. 3 navigation receiver Certain reference significance.

In order to solve the problem of low data accuracy due to UAV height sensing equipment such as GPS, barometer, ultrasound, etc., a control system used on multi-rotor aircraft was designed to achieve UAV autonomous altitude cruise. In response to this problem, we introduce an inertial measurement unit (IMU), and use the IMU to calculate the system acceleration (ACC), and use the Kalman algorithm to predict altitude, thereby eliminating altitude drift caused by insufficient sensor accuracy and errors. In addition, the ADRC-PID joint control algorithm is also introduced to control the attitude of the aircraft, achieve control compensation, and finally control the height of the drone through the three-loop cascade PID.

At present, most unmanned aerial vehicles (UAVs) are powered by traditional aero modelling lithium batteries, which have poor endurance and cannot operate continuously for a long time. It greatly limits the application fields of UAVs. To tackle this problem, we design a fully-automatic UAV docking platform that can work under no human situation and assistance to charge the aircraft with insufficient power to help the drone extend its battery life. It also provides an implementation solution for a fully automatic drone docking platform with wireless charging, UAV takeoff and returns, auxiliary positioning, and relay communication. The system mainly includes apron part, docking platform protective shell, solar panel, power conversion equipment, wireless charging base, satellite positioning and communication module, radio positioning signal generator, and radio relay communication module, etc. The power system of the apron part uses electric pushrods.

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Abstract. GFSK modulation is an wireless communication standard for the purpose of Automatic Meter Reading (AMR) in smart grid. This paper presents the implementation of GFSK digital receiver based on CORDIC algorithm. The receiver is made up of the frequency offset estimation, frequency compensation, bit synchronization and demodulation modules. The digital receiver is equipped with two identical baseband signal processing branches, in which a large carrier frequency offset can be accommodated.