Thejesh N. Bandi, Department of Physics & Astronomy, College of Arts & Sciences, The University of Alabama

View Abstract Sign in for premium content


Rubidium Atomic Frequency Standards (RAFS) are the workhorses of the Global Navigation Satellite Systems (GNSS). RAFS have an established space legacy, proven reliability and are well suited as space payloads due to their low Size, Weight, and Power (SWaP). RAFS of existing systems such as GPS, Beidou and Galileo have space heritage of 20 to 50 years. The Indian navigation program, known as the Navigation with Indian Constellation (NavIC) started in 2013 with the launch of its first satellite by adopting clocks similar to the Galileo navigation system. Although there have been efforts since 2009 towards the development of an indigenous RAFS, the clock design from the basic design of the Physics Package (PP) was started mid-2015. The Indian Rubidium Atomic Frequency Standard (IRAFS) has been successfully designed, developed, characterized, tested and space qualified in under seven years, while the clock development and the test facilities were also developed in parallel. In this paper, the core designer and lead scientist of the IRAFS development and clock development team at the Space Applications Centre, Indian Space Research Organisation (ISRO), presents and discusses the challenges of developing and testing a space state-of-the-art RAFS. The unique engineering problems faced during the space clock development will be discussed and the novel design features of the IRAFS’s Physics Package (PP) and electronics will be highlighted along with the operational requirements. Additionally, the key differences and challenges of a high-performance space clock requirements in terms of reliability, robustness and operability as compared to that of the terrestrial clocks will be examined. Finally, the impact of IRAFS in context of the Indian space program and the potential future possibilities with IRAFS will be outlined.