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Upper-Air Sounding System


Contact Information

University and Department:     Ural State Technical University, Institute of Radio Engineering, department of Technology and Communication Facilities

Team Members:     Oleg Chernykh,     Oleg Plokhikh

Faculty Advisors:     Vyatcheslav Ivanov

Primary Telephone Number (include area and country code): (7-343)-3754762

Project Information


Describe the challenge your project is trying to solve.

The upper-air sounding systems are applied to direct atmospheric parameter measurement (temperature, humidity, wind etc.) by launching the radiosonde in free flying. The radiosonde is launched on gas-filled balloon or is dropped with a special parachute from an aircraft. Measured by the radiosonde meteorological data are transmitted to the ground tracking station via a meteorological radio band telemetry link. Height of sounding is up to 30 km, distance more than 100 km. There are high measurement accuracy requirements to the system. The radiosonde should have small weight, low cost and low emitting power.

Mathematical atmosphere models are used for weather forecasting by results of measurements of a meteorological station network. According to them atmospheric parameters in upper-air sounding systems are measured relative to atmospheric pressure levels. The atmospheric pressure is measured by appropriate radoisonde sensor, or is calculated using the barometric formula expressed through height, temperature and humidity of an air. In some application the atmospheric parameters are measured relative to height.

In traditional upper-air sounding systems the radiosound speed and coordinates are measured by radar or, for want of use of the pressure sensor, by direction finding. Alternative is the coordinate and speed definition using a satellite radio navigational system. This method gives advantages on accuracy of wind and height measurement and dimensions of ground equipment.

Describe how you addressed the challenge through your project.

Our team has designed the development type of the upper-air sounding system intended for experimental check of system availability and performances. The system consists of the radiosonde and tracking ground station. The tracking ground station is based on PXI chassis and consists from:

  • NI PXI-1044 chassis, in which the      necessary PXI units are installed;
  • NI PXI-5661 RF Vector Signal Analyzer;
  • NI PXI-5690 RF preamplifier;
  • NI PXI-8105 PXI Embedded      Controller with installed Windows XP operational system and drivers;
  • receiving antenna of radiosound      signals;
  • special software for tracking station,      developed in the NI LabVEIW;
  • input-output devises (monitor,      keyboard, mouse).


The radiosonde hardware is mounted in heat-insulating case and consists of the microprocessor control and measurement module with connected temperature and humidity sensors, transmitter, navigational receiver and battery power supply unit. The coordinates and speed are determined by the small-sized GPS receiver. The radiosound measures a temperature and humidity using high precision sensors. The microprocessor module measures output sensor signals, receives the navigation data, builds a digital package for transmission to the ground tracking station and controls a transmitter operation.

The telemetry data is transmitted continuously. The data are updated every 2 seconds. The data rate is 2.4 kbit/s. The transmitter uses frequency manipulation of 400- 406 MHz carrier frequency with deviation 2.4 kHz. In each the two second time interval the telemetry information is repeated multiple times. This redundancy is used by ground station software for an error-correction in received bit stream.

The ground station receives radiosonde signals with the undirected antenna. The received signal is amplified by the NI PXI-5690 RF preamplifier, and then it is fed on the NI PXI-5661 vector analyzer. Thus, the sensitivity of the receiver is increased up to -165 dBm/Hz. The high sensitivity of receiving hardware provides necessary operation range of a radio link for the transmitter with output power about 100 mW.

The ground station software desined in the LabVIEW environment (except for the library for data types substitution developed in Microsoft Visual Studio C ++) decides the following problem:

  • the radiosonde signal      demodulation and automatic frequency control
  • data burst discrimination and bit      error correction
  • secondary processing of the      telemetry and navigation data
  • displaying the measured      atmospheric data (temperature, humidity, direction and speed of a wind)      and auxiliary data (height, distance) in form of the graph
  • setting up the ground station      hardware and software
  • displaying the diagnostic      information about system operation, saving of obtained data in a file

In comparison with radar upper-air sounding systems the ground station of the designed system has small dimensions, weight and lower power consumption due to simplification of antenna. The GPS technology gives higher accuracy of coordinate and wind definition in upper layer of atmosphere.

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