Pisharoty Sonde system is an indigenous GPS Sonde (Radiosonde) system developed by VSSC/ISRO using commercially off the shelf components (COTS) for high quality atmospheric parameter measurement.


The Sonde system consists of the balloon borne segment referred as Pisharoty Sonde and the ground segment referred as Pisharoty Sonde Ground Station. Pisharoty Sonde uses sensors for measuring the atmospheric temperature & relative humidity and GPS receiver module for acquiring the wind parameters, altitude, date and time. Pressure information can be derived from the height and temperature information using software. Sensor and GPS data are processed and transmitted to ground station. Pisharoty Sonde Ground Station consists of the Antenna Assembly & LNB, Receiver and Data Processing & Display unit. Sonde system incorporates the software for solar radiation correction on temperature measurement.

                                                                 Fig. Sonde on ascent                                      Fig.      Sonde  Ground Station

The Sonde system also generates the WMO specified ‘temp’ messages for reporting the data. This indigenous low cost system is compact and light weight (125 grams). Pisharoty Sonde system is validated by comparison ascents with various internationally available Sonde systems and the performance is confirmed. The system performance is evaluated independently by IMD and cleared for meteorological applications. More than 12000 Sondes have been already realized by ISRO.


Specifications of Pisharoty Sonde System

A. Sonde

      Frequency                 : 400 to 406 MHz (user programmable)

      Power                        : 17 dBm (50 mW)

      Size                           : 12 cm x 11.5 cm x 9 cm

      Weight                       : 125 gm

      Battery                       :  up to 4 hours operation


B. Ground Station Receiver

      Frequency                 : 400 to 406 MHz (user programmable)

      Sensitivity                 :-117 dBm @ 1x 10-3 BER

      Connectivity              : Ethernet

      Power Supply            : 220-230 V AC, 50 Hz

      Battery Backup         : 6 Hours


      Size                           : 47.5 cm x 23.5 cm x 4.5 cm (19 “ rack mountable)






Response time


0 to 1030 hPa

±1.4 hPa (>100hPa)

±0.5 hPa (≤100hPa)




-90 to 60 °C




Relative Humidity

0 to 100%

±5 %



Velocity range

0 to 500 m/s




 *Pressure is derived from altitude



The Pisharoty Sonde System is used by scientists for boundary layer studies and upper atmospheric observations. Pisharoty Sonde system is used by Space Physics Laboratory (SPL) VSSC, MET TERLS VSSC, MET/SHAR, SAC, NESAC, NRSC and various universities for atmospheric studies. Data from the System is used regularly to support ISRO’s satellite launches. The System is identified as part of network of weather stations for thunderstorm observation in SAARC countries. Huge market demand also exist in atmospheric measurements by IMD, defence and academic institutions.


ISRO is willing to offer the knowhow of this technology to suitable entrepreneurs / industries in India. Capable manufacturing industries interested in acquiring this knowhow may write with details of their present activities, requirements and plans for implementation, infrastructure and technical expertise available with them, their own market assessment, if any, and plans for diversification to the address given below:


Technology Transfer & Industrial Coordination Division (TT&IC)

Vikram Sarabhai Space Centre, ISRO PO

Thiruvananthapuram-695 022

E mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

Ph: 0471-2564081

Fax: 0471-2564134

Ph: 0471-2564081/2565133/2565695

Fax: 0471-2564134