The Sun-Earth system is a complex system influenced by a wide variety of physical processes over multiple spatial and temporal scales. These processes include magnetic reconnection, plasma acceleration, particle precipitation, formation of complex current systems in the terrestrial magnetosphere and ionosphere, modfications of the ionospheric electric fields and winds, and the impact on electrical, electronic and biological systems both in space and in ground. Space Weather is a field of research that provides new insights into the complex influences of the Sun on interplanetary space, the Earth's magnetosphere, ionosphere, and thermosphere, on space- and ground-based technological systems, and beyond that on their endangering effects to humans in space. Space weather impact monitoring is therefore, a highly relevant subject of research for our modern society as we are increasingly getting dependent on these technological systems. To address this aspect, nations across the globe including India have been pursuing research concerning Sun, solar processes and their evolution from solar interior into the interplanetary space, and their impact on Earth’s magnetosphere-ionosphere-thermosphere system. In India, over the years, a substantial amount of work has been done in each of these areas, and based on these, it has been realized that simultaneous measurements from different regions from polar to equatorial laitudes is required to obtain comprehensive understanding of the space weather and its effects in the terrestrial upper atmosphere.

     In this context, with an objective to monitor the impact of Space Weather Events on Indian Low latitude Upper Atmosphere-Ionosphere System, the Space Physics Laboratory (SPL) of Vikram Sarabhai Space Centre (VSSC) in Trivandrum has initiated a long term science program called, Indian network for Space Weather Impact Monitoring (InSWIM). The main objective of this program is to obtain comprehensive measurements of ionospheric parameteres from a network spanning across many strategically chosen locations in the country for space weather studies. It envisages to study the space weather effects on the Indian ionospheric region and formulate an Ionospheric Model which would be helpful in ascertaining the impact of ionospheric variations on GPS/IRNSS Radio signals.

     Under the aegis of this program, dual frequency, multi-satellite GPS Receiver systems have been installed at various places in India. Currently nine of such receivers are functioning at Trivandrum, Port-Blair, Bangalore, Kadapa, Hyderabad, Bhopal, Delhi, Hanle and Pune. In due course, the present chain of stations would be extended further to add several new stations over different latitude and longitude regions in India. To enhance the scope of the Science, the presently existing chain of LEO (Low-Earth Orbiting satellite) radio receivers catering to SPL’s coherent Radio Beacon Experiment (CRABEX) for ionospheric tomography has also been made a part of the InSWIM Network. Subsequently, in later stages of InSWIM, other complementary instruments, like Magnetometers, Airglow photometers, etc, would be added to selected stations in a phased manner. The SPL-VSSC, Trivandrum will serve as the repository of the InSWIM data and the nodal centre to coordinate the program. The program involves participation from national research institutions and universities, making it by far the most ambitious space weather research initiative of the country. With the evolution of this program, facilitation of individual stations with a financial support for the upkeep, and maintenance of the systems is also envisaged.