Currently, radar sensing of the atmosphere using a telemetric transponder on board a balloon probe is one of the main means of obtaining the highest quality data on the state of the troposphere and the lower stratosphere. Temperature, pressure, humidity, wind direction and speed are measured daily at the aerological sensing stations integrated into a single network. In some locations (cosmodromes, airports, etc.), sounding is performed much more often. As a telemetric transponder on board the balloon probe, a super-regenerative transceiver (SRT) is currently used, forming a response pause in its radiation to the impact of the radar's request radio pulse. In the intervals between the pulses, the SRT provides multi-channel transmission of telemetry data received from the corresponding sensors by means of modulation of superimposing pulses. The wind parameters are obtained in the radar based on the determination of the inclined range to the aerological radiosonde (ARS) by the delay time of the response pause and angular data taken from the antenna drive sensors. The problem of using SRT in atmospheric radiosonding systems is the difficulty of ensuring the stability of its operation in the temperature range. In conditions of a low signal-to-noise ratio at the output of the radar receiver, when the ARS approaches the maximum range of the system, disruptions of tracking are observed. In addition, the asynchrony of the processes of forming the receiving window of the SRT and sending the request radio pulses of the ground radar causes additional fluctuations in the time position, depth and duration of the response pause. This is the reason for the fundamentally unavoidable component of the additional measurement error of the inclined range to the ARS. The sensitivity of the SRT in the reception mode is limited by shock vibrations inherent in the super-regenerative mode of operation of the microwave oscillator during the formation of the leading edge of the radio pulse. The next drawback is fundamental - a wide spectrum of radiation (4…6 MHz), which creates problems of electromagnetic compatibility of radio-electronic means, for example, the operation of GLONASS / GPS systems. It should also be noted the insufficient noise immunity of the SRT from the effects of active interference. When interference occurs at the receiving frequency, the SRT forms false response pauses. In case of prolonged interference, the operation of the channels for measuring the range and receiving telemetry information of the radiosonding system is disrupted. An additional disadvantage of the SRT is the complexity of its configuration during the production of ARS. It is connected with the fact that changes in one of the parameters entail a change in the other, for example, adjusting the excitation conditions of the oscillation of the microwave oscillator causes a change in its carrier frequency. The totality of the listed disadvantages of the SRT is a complex and complex problem on the way to further development of atmospheric radiosonding. It consists, first of all, in the need to increase the sensitivity of the transponder in the mode of receiving a request radio pulse, as well as the depth and duration of the response pause. In addition, solutions to problems that narrow the radiation spectrum and reduce fluctuations in the time position of the response pause are in demand, as well as a significant increase in its noise immunity to the effects of active interference and simplification of tincture. One of the prospects for a radical solution to this problem and the further development of atmospheric radiosonding is to replace the SRT with autodyne transceivers (AT). To date, there are several technical solutions for the implementation of the transponder and radar equipment, in which the AT is used while maintaining, and in some cases expanding the functionality of the transponder. This article is devoted to the description of the technical solutions of the AT proposed by us, using the asynchronous mode of receiving the request radio pulse of the radar on board the ARS. It is also shown that the transition in atmospheric radiosonding systems from the use of SRT to AT provides a cardinal solution to the problem of improving the spectral characteristics of AT radiation and eliminating fluctuations in the time position, depth and width of the response pause. Processing of the request radio signal on board the ARS with the AT increases the stability of the transponder operation mode at a low signal-to-noise ratio and improves its noise immunity to the effects of active interference. The use in the AT of a closed system of automatic stabilization of the level of the request radio signal at the input of an autodyne microwave oscillator provides an increase in the stability of the mode and reliability of the operation of the microwave oscillator over a wide range of distances. In the process of launching and lifting the ARS, this range is expanded from the location of the radar to the range limit, limited by the energy potential of the radiosonding system and the terrain. The first option for creating a closed stabilization system is based on the use of a controlled attenuator between the antenna and an autodyne microwave oscillator, which is controlled by an output signal of the delayed AGC type. The second variant of the stabilization system includes a chain of direct action on the autodyne microwave oscillator and a chain of information feedback on the results of this action. In this case, the direct action circuit contains a power-adjustable radar transmitter and a transmission path of the request radio pulse from the radar to the ARS. The information feedback circuit on the results of exposure to the autodyne microwave oscillator is represented by a radar receiver that controls the magnitude of the autodyne deviation of the frequency of the response radio signal received from the autodyne microwave oscillator ARS. A method for determining the range to the ARS is proposed, based on fixing the moment of receiving the response of an autodyne microwave oscillator to the impact of a radar radio pulse by means of a radar receiver with a frequency detector. Due to the exclusion of fluctuations in the time position of the response signal and the hardware delay of the radio signal, it provides an increase in the accuracy of determining the range from the radar to the ARS. The proposed method makes it possible, while maintaining the functionality of the known AT, to significantly simplify its design, which reduces the cost of manufacturing ARS. In this case, the autodyne signal isolation unit, the amplifier, the request signal detector and the response pause pulse oscillator are excluded. It should be noted that the introduction of the proposed methods and devices into existing radiosonding systems will require only minor design changes in the radar associated with the introduction of a frequency detector into the receiver of the range channel, and the adjustment of the frequency of the request transmitter by the value of the difference frequency of the beat signal. The results of the performed studies of the transistor AT at a frequency of 1680 MHz confirmed the feasibility of the proposed method and its suitability for use in the prospective development of an atmospheric radiosonding system. The presented descriptions of the proposed technical solutions of the AT are given by the example of the execution of blocks and nodes on semiconductor devices and integrated circuits. Taking into account the wide need for ARS on the atmosphere radiosonding network, the proposed AT can be implemented in an integrated design with digital processing and signal generation. At the same time, some complication of the design of the AT will not cause significant energy consumption of the on-board power supply and will not lead to an increase in the dimensions and weight of the ARS.
Translated title of the contributionDEVELOPMENT OF RADAR SYSTEMS FOR SENSING THE ATMOSPHERE USING ASYNCHRONOUS AUTODYNE TRANSPONDERS
Original languageRussian
Pages (from-to)45-63
Number of pages19
JournalУспехи современной радиоэлектроники
Volume78
Issue number1
DOIs
Publication statusPublished - 2024

    Level of Research Output

  • VAK List

ID: 55404233