Quantum Technologies

Positioning and navigation has been key to the growth of human civilization since time immemorial. With the increasing demand for improved accuracy in positioning and navigational applications, the demand for measurement of time has also increased significantly. At the heart of the most precise time-keeping devices ever built by mankind are precision atomic clocks. Atomic clocks come up in different sizes and applications ranging from lab based optical atomic clocks to chip scale atomic clocks (CSACs) that make use of miniaturized components to establish a precision time reference.  

Atomic clocks on-board GPS (global positioning systems) satellites play a critical role in positioning, navigation, and communication networks. The signal transmission and position quality obtained by a GPS system directly depends on the timing reference and relative difference in signal times determined by the on-board atomic clocks present inside the satellites. Atomic clocks in a satellite constellation form the heart of the GPS system. These on-board atomic clocks are synchronized in a manner such that the time difference of different satellites positioned at different orbits are used to measure the accurate location of a navigation receiver or an object on the Earth using a technique called trilateration. 


GPS technologies are directly reliant on the accuracy and stability of atomic clocks. GPS is used on a routine basis to obtain accurate coordinates of important geographical locations and geo-features, geodesy, emergency mapping and establishing connectivity in the neighbourhood for civilian and strategic applications. GPS systems ensure seamless coordination of satellite-based communication systems along with the civilian air and land-based navigation and also mobile and internet networks. With increasing use of on-board GPS systems in drones, UAVs (unmanned aerial vehicles) and associated air-borne and land-based systems, there has been a landmark change in industrial and agricultural output. Drone based farming technologies are on the increase. UAVs and drones are being extensively employed for reconnaissance, security and defence missions. And finally, precision guided munition systems and secure communication form the core of modern warfare technology, which are very much reliant on precision timing sensors, especially on portable atomic clocks.


Precise atomic clocks are key to not only establishing superior GPS and navigation systems but a whole host of scientific endeavours such as VLBI (Very Long Baseline Interferometry) - important for timing synchronization of radio telescopes that help image galactic events and phenomena, enables spacecraft navigation (space geodesy) and aids allied industry such as development of precise timing devices for mobile and internet communication and also for time stamping financial transactions in banking and stock-exchange systems. Recently, VLBI technology was used to take the first ever of a Black Hole by time synchronizing multiple radio telescopes spread over the globe using precision atomic clocks. 


With increasing penetration of the internet connectivity, it has become imperative to ensure accurate network timing synchronization to ensure seamless connectivity to billions of users hooked up to the Web. Additionally, over the past few years position based social media services and entertainment systems have witnessed a phenomenal growth. With this growth, has also increased the demand for precise network timing systems. Conventional hardware (FPGA - Field Programmable Gated Array) based network timing devices are slowly reaching their limit. Atomic clocks can help surpass this limitation with timing accuracies of a few parts in 10^-18.

Time keeping has been at the core of the evolution of human civilization. With each progress in the accuracy of measurement of time, our understanding of nature as well as the impact on our daily lives has changed tremendously. Today’s time keeping is done with state-of-the-art atomic clocks. The fundamental principle on which these atomic clocks operate is through a frequency measurement of a narrow atomic resonance that has been made accessible through tremendous developments in laser cooling and trapping, laser stabilization and laser spectroscopy. However, given the complexity, spatial footprint and energy requirements of these atomic clock systems, their penetration into the space and defence industry has been limited. These are the reasons why there is currently a sustained global activity related to research and development programs for developing portable atomic clocks. Portable atomic clock technology has gained a tremendous push as a fundamental application in the quantum sensing domain under state-of-the-art quantum technologies. 

With the establishment of Global Navigation Satellite Systems (GNSS; most prominently the Global Positioning System GPS) accurate positioning and navigation has found its way into virtually everybody's pocket in the form of compact and cheap chipsets in mobile phones. GNSS or GPS signals, however, are prone to certain technical limitations. Heavy tree coverage, urban or mountainous terrain, or tunnels lead to positioning errors or total loss of signal which makes navigation, e.g. for flying in challenging terrain difficult to impossible. Inertial navigation allows determining one's position by knowing the starting position and continuous determination of all three translational and rotational degrees of freedom followed by integration and use of Newtonian physics. In practice, however, GNSS-free navigation over extended periods of time is troublesome since it leads to positioning errors due to intrinsic noise and drift behaviour of classical inertial navigation systems (INS). Atomic clocks can come to the rescue of users in such scenarios by improving the holdover time with respect to a reference signal sourced from the on-board clocks in GPS satellites.

At IIT Tirupati, under the Technology Innovation Hub (TIH) in the Positioning and Precision Technologies (PPT) vertical, we are interested in developing technology for the next generation quantum positioning systems and precision timing sensors that may enable a paradigm shift in how present-day positioning, navigation, and communication systems operates. We hope that through innovation and technology development in the area of portable atomic clocks, we shall be able to cater to the increased demands of the nation and society for enhanced and improved applications in the civilian and strategic sectors. We seek collaboration and support from relevant stakeholders within the industry and academia to help us achieve our objectives.

As part of our objectives to make the nation self-reliant (Atma-Nirbhar) in the niche area of positioning, navigation and secure communications, we are aiming to develop India’s first portable, transportable, all-optical, trapped-ion atomic clock for next generation quantum positioning, navigation and communication applications. Trapped-ion technology has become sufficiently mature to enable miniaturization of key components including lasers and optics. In addition, fiber-based beam delivery and diagnostics will aid to the lowering of the spatial footprint and power requirements to operate the system. We are developing a trapped ion all-optical portable atomic clock using a single calcium (40Ca+) ion.


At the heart of all GPS systems for communication and navigation purposes lies an atomic clock for precise time synchronization and time delay calculations. Optical clocks represent the pinnacle of precise timekeeping. The most precise atomic clocks are based on extremely narrow optical transitions (linewidth ~ < 1 Hz) within neutral atoms or trapped atomic ions. Through the tremendous progress made in laser stabilization technology at extreme precision, optical frequency combs, laser cooling and trapping of atoms and ions. These developments have allowed the realization of optical atomic clocks with unrivalled performances and fractional uncertainties well below 10^-17, finding game-changing applications in fundamental physics tests, relativistic geodesy and time and frequency metrology. Apart from these fundamental applications to understand nature, such optical atomic clocks shall serve to define primary and secondary time standards in the near future.


The primary target beneficiaries are as follows:

  • Global positioning systems (GPS) for civilian (NaVIC) and defence purposes
  • Defence services (warhead delivery, secure communication, and navigation)
  • Timing devices for ISPs (internet service providers)
  • Timing devices for mobile networks and mobile communication
  • Network synchronization
  • Disaster management through GPS
  • Financial time stamping
  • Mobile manufacturers
  • Transportation
  • Power stations, power networks and power grids
  • GPS IoT enabled Smart city applications
  • Mining, mineral exploration and earth geodesy
  • VLBI (Very Long Baseline Interferometry)
  • Deep space navigation and space geodesy

Lead
Dr. Arijit Sharma, Asst. Professor, Dept. of Physics, IIT Tirupati


Team :

Academia:

  • Dr. Subhadeep De, Assoc. Professor, IUCAA Pune
  • Dr. Umakant Rapol, Assoc. Professor, IISER Pune
  • Dr. Sadiq Rangwala, Professor, LAMP Group, RRI Bengaluru
  • Dr. Subhasis Panja, Senior Scientist, NPL, New Delhi, India
  • Dr. M. S. Giridhar, LEOS Unit (ISRO), Bengaluru
  • Dr. Umesh Kadhane, Assoc. Professor, IIST Trivandrum
  • Dr. Dmitry Budker, Professor, JGU Mainz Germany and UC Berkeley, USA
  • Dr. Thejesh N. Bandi, Assoc. Professor, University of Alabama, USA
  • Dr. Amar Vutha, Assoc. Professor, University of Toronto, Canada

Industry:

  • SAC (ISRO), Ahmedabad
  • DRDO, New Delhi and RCI (DRDO) Hyderabad
  • XILINX India, Hyderabad (Multi-national)
  • New Age Instruments & Materials Pvt. Ltd., Gurgaon - 122001, Haryana, INDIA 




 

 

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