India's space agency, ISRO, successfully launched a satellite crucial to the country's satellite navigation system using the GSLV rocket.
The NVS-01 satellite is the initial satellite in the second-generation navigation satellite series developed by the UR Rao Satellite Centre of ISRO in Bengaluru. Currently, India relies on its NavIC series of satellites to provide navigation, positioning, and timing services for civilian and defence purposes within India and up to 1500 kilometres beyond its borders.
The NVS series of satellites aims to support and expand the capabilities of NavIC with improved features. These satellites will introduce L1 band signals to broaden the range of services offered. Notably, the NVS-01 satellite will also include an indigenous atomic clock, a significant milestone for ISRO.
Atomic clocks are extremely accurate timekeeping devices deployed within satellites. They provide time measurements with precision down to the nanosecond, which is equivalent to one billionth of a second. This level of precision is crucial in ensuring accurate positioning services.
When utilising satellite-based positioning and navigation services, our position is determined by calculating the distance from multiple satellites.
This calculation involves multiplying the time it takes for signals to travel with the speed of the signal, which is nearly the speed of light. In such calculations involving large values, even a tiny variation of a billionth of a second can result in an incorrect distance measurement, leading to inaccuracies in positioning by several meters or even tens of meters.
To address this, the presence of atomic clocks becomes essential. These clocks are designed to operate for several years without experiencing errors in timekeeping at the nanosecond level. Their exceptional accuracy ensures that precise time measurements are maintained consistently, allowing for accurate distance calculations and reliable positioning services.
In a statement to reporters before the launch, Dr. S. Somanath, Chairman of ISRO, revealed that only four of India's current NavIC satellites were operational. Instead of replacing the three non-functional satellites from the previous generation, ISRO has decided to launch a set of five next-generation NavIC satellites, with NVS-01 being the first among them.
The reason behind launching a new fleet of five satellites is that the existing constellation is expected to reach the end of its mission life in a few years. Therefore, it is not advisable to simply replace the old fleet. The plan is to launch two next-generation NavIC satellites annually.
Image Source: Republic World