Design Of Temperature Stabilized System For GNSS Receiving Antenna

The generation and maintain of standard time require the use of remote time comparison technique. GNSS time transfer technology based on navigation satellite is a kind of high precision and long-distance time frequency transfer technology. It is widely used in the high precision time comparison between different laboratories. In recent years, the precision of GNSS precise single point positioning time comparison based on the carrier phase observation value is up to Ins. GNSS receiver is one of the main equipment for the GNSS time comparison and the carrier phase time comparison. With the elimination of the error sources in the time comparison technique, the accuracy of time comparison is further improved, and the influence of temperature change is becoming a very important source of error. In this paper, designed the GNSS receiving antenna of both heating and cooling system of temperature stabilized system based on the FPGA, designed to reduce the impact of temperature change on the GNSS receiving antenna. The heating mode temperature stabilized system used for GNSS receiving antenna is established, and the accurate control of temperature is realized. The test results show that the temperature fluctuation in the temperature stabilized system is ±0.25℃. The main contents of this paper include:(1) In depth Study of temperature control theory and common control algorithm, combined with temperature changes impact on GNSS receiver antenna, leads to the design of GNSS receiving antenna system with temperature stabilized, propose the temperature control algorithm for GNSS receiver antenna.(2) According to the working characteristic of GNSS receiving antenna, propose the design requirement of temperature stabilized system According to the design requirements, the hardware system and the control algorithm of the temperature stabilized system are designed. It mainly includes:the design of the physical structure of the temperature stabilized system, the design of the heating/cooling system, the design of the temperature monitor circuit and the design of the temperature control circuit. And then design the control algorithm of temperature control system. Mainly includes the temperature control algorithm and parameter self-tuning algorithm.(3) According to the temperature stabilized system design, the GNSS receiving antenna temperature system’s realization on FPGA is introduced in detail. Mainly include:the realization of temperature monitoring circuit, temperature control circuit and the realization of temperature control algorithm. The realization of temperature monitoring circuit includes the communication between the temperature sensor and the FPGA, and the communication between the digital tube and the FPGA. Realization of temperature control circuit including pulse width modulation (PWM) on FPGA. Realization of temperature control algorithm including the PID algorithm and the fuzzy PID algorithm on FPGA.(4) Through the test of the GNSS receiving antenna temperature system in the actual environment, it is concluded that the temperature in the temperature stabilized system is stable, the temperature fluctuation is ±0.25℃.