TARDIS laser beam at John Bryan Observatory. (US Air Force photo by Steve Zuraski)
Published May 6, 2022
By Air Force Life Cycle Management Center Public Affairs
The Air Force Life Cycle Management Center Engineering and Technical Management Directorate (AFLCMC/EN-EZ) is collaborating with Air Force Research Laboratory Sensors Directorate (AFRL/RY) and the Air Force Institute of Technology Center for Directed Energy (AFIT-CDE) to advance state-of-the-art research with a unique patented laser sensor system that measures turbulence in the atmosphere above the laser, while allowing AFLCMC Palace Acquire new hires (PAQs) and part-time interns to demonstrate STEM technology development.
The Turbulence and Aerosol Research Dynamic Interrogation System (TARDIS) is an invention of several researchers at AFRL/RY and AFIT. TARDIS detects turbulence by using a laser beam and timed sensor to measure pulse reflections from different atmospheric layers to create a profile along the beam. Knowledge of turbulence is a key parameter for optimizing long range imaging and laser propagation. The system has been built under a research collaboration between RY and AFIT-CDE. Then PhD graduate student Steven Zuraski first built a prototype system in the AFIT-CDE lab under the guidance of co-advisors Dr. Steve Fiorino, CDE Director, and Dr. Elizabeth Beecher, then AFRL/RYMT Electro-Optical/Infrared (EO/IR) Space-Based Sensing Team Lead.
Next, under research contracts funded by AFRL/RYMT and AFIT-CDE, a real world TARDIS was constructed by leveraging an existing 24 inch quad-axis telescope located at contractor Applied Optimization’s observatory facility located at John Bryan State Park. TARDIS has been operational and taking data throughout 2021. Zuraski completed his dissertation work with data collected by TARDIS and graduated in September 2021. He has also recently published two journal articles, five conference papers, and two invited talks on his research with TARDIS, one of which received “Editor’s Choice” for scientific excellence and was a top download that month.
To operate a high powered laser (see photo) shooting up into the sky, several approvals have to be orchestrated prior to every evening’s data collection. The Laser Clearinghouse (CSpOC/SPD) has to confirm there are no celestial objects that could be sensitive to the laser orbiting overhead. The Federal Aviation Administration (FAA) has to be notified so that they can publish a Notice to Airman. In addition, the FAA requires that two human spotters be constantly scanning the sky to verify that no air traffic is coming close to the ‘keep out zone’ of the laser beam, and to tell operators to shut down the laser if an aircraft seems to be heading towards the laser.
Recently, several AFLCMC/EZA Avionics Engineering Division PAQs and interns volunteered to serve as laser safety spotters at the laser observatory site at John Bryan State Park. This involves working at night outside scanning the skies to locate aircraft flying around the observatory, then notifying the laser operators if the aircraft gets too close to the beam. AFLCMC interns Mahmoud Abouzahra, Jason Dong and Jennifer Swabb worked as spotters.
One of the benefits to this job is learning more about astronomy, atmospherics, how the laser system operates and seeing the laser beam propagating into the night sky.
“Spotting at JBO [John Bryan Observatory] was a great experience! As someone interested in electro-optics, seeing the laser in action was inspirational,” Swabb said. “I'm glad I got the opportunity to work with the folks at JBO and help out with the project.”
Another team of AFLCMC PAQs and interns worked over the past year developing and building an Automated Dependent Surveillance Broadcast (ADSB) detection and monitoring system called GeoFence. The team consisted of multiple interns including Arikka Knisely, Ethan Morris, Maxwell Nguyen, Tori Fuenfgeld, Erin Rogers and Andrew Mitchell.
Ryan Wolfarth, Electronic Warfare Technical Expert and Dr. Beecher, currently EO/IR Technical Expert, both assigned to AFLCMC/EZAD, recognized that the ADSB GeoFence sensor had potential to improve laser safety by detecting aircraft at a greater distance and predicting laser intercept. The ADSB technology is a GPS-based transponder upgrade for aircraft that constantly broadcasts identity, location, altitude, and velocity. As of 2020, the FAA now requires all aircraft with electrical systems to emit the ADSB signal, making air traffic control much easier for the FAA and pilots. Beecher and Zuraski worked with the intern team to improve the usability and customer interface. Late last year, two interns and Ryan Wolfarth took the system to John Bryan State Park and did an initial demonstration of GeoFence at the observatory.
“With only three months of effort, the team was able to demodulate ADS-B messages and display aircraft in the vicinity of the observatory on a real-time display,” Wolfarth said. “While there is more work to be done, what most impressed me was the independence and maturity that this team exhibited while planning and executing the demonstration.”
“This will allow the spotters on-site at JBO to better distinguish aircraft as potentially entering the laser hazard area, and also allows for further advanced warning of aircraft in the area,” Dr. Zuraski said.
Indeed, this ADSB detector and unique display offers a custom system that would benefit any research field test that needs to be aware of local air traffic.
AFIT-CDE and AFRL/RY have arranged for funding to continue TARDIS research throughout 2022. Future AFIT students, AFRL researchers and AFLCMC interns will benefit from the continuing collaborations and field test data that will be obtained with TARDIS and GeoFence.
JBO laser with safety spotters outside observatory. (US Air Force photo by Dan LeMaster)