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Beidou/GPS Upper Air Sounding System

17-04-2014Source:China Meteorological News Press

1) Overview

GPS radiosonde is mainly made up of GPS receiving and processing module, temperature or pressure (optional), humidity sensors, data acquisition module, signal coding modulation module and batteries. Applying GPS antenna, GPS receiving and processing module is designed to receive signals from four or more GPS satellites and acquire longitude, latitude and height and other parameters of GPS radiosonde in a real-time manner. The temperature or pressure (optional) and humidity sensors are able to measure high-altitude temperature, pressure (optional), humidity and other atmospheric parameters, the data of which are converted into digital signals through the data acquisition module. Signal coding modulation module is responsible for encoding location and sensor information and modulating encoded data streams, forming carrier signals with the center frequency of 403MHz which are transmitted to ground receiving-processing equipment.
Ground receiving and processing equipment, mainly involving UHF antenna, radiosonde signal receiving and modulating module, data terminal, calibrating tank and battery, is designed to receive, modulate and process radiosonde signals. Radiosonde signal receiving and demodulating module is designed to receive the measured data transmitted by GPS radiosonde, demodulate and transmit such data to data processors. Data processors are responsible for data frame decoding and processing at the demodulation module, and restore the original data from demodulated data involving three-dimensional position of the radiosonde, temperature or pressure (optional) and humidity sensors. Then it calculates wind speed and wind direction, enabling real-time data archiving, and provides output data in specified format in accordance with the provisions of China Meteorological Administration and users’ requirements. As a component of measuring sensors and a type of comprehensive detection equipment, calibrating tank is used for measuring base values before radiosonde is discharged and correcting measurement errors by sensors.

Upper-air Sounding System

 

2) Features 

Simple structure, highly automation and good maneuvering performance. It can be applied on the ground as well as on movable platforms (such as vessels, airplanes and vehicles), and thus it can fulfill the task of meteorological support anytime and anywhere.

The accuracy of anemometry is faster than 0.3 m/s, significantly improved accuracy of anemometry and hypsometry. As an upper-air sounding system of a new generation, it adopts new kind of temperature, pressure and humidity sensors to improve sounding quality.

Narrow frequency bands and little interference.

Passive receiving system results in the state of electromagnetic concealment of the ground receiving system.

 

3) Technical parameters

 

4) Terminal application system of the sounding system

Main interface of the terminal application system of the sounding system and antenna control display

PTU curve and radiosonde track

Historical data playback and calibrating

 

5) Site selection

The monitoring center station of the automatic sounding system should be built where there are no high mountains, tall buildings, lofty forests, iron tower, high-voltage equipment and other shelters. Besides, it should be guaranteed that there be no electromagnetic interference to other radio equipment. The electromagnetic environment test for the station is required to pass through the determination by related functional institutions with the frequency range of 403±3MHz. Frequency protection by local radio management departments is also required. 

Layout of upper-air sounding system

 

Editor Hao Jing