The recent escalation between the United States and Iran concerning the oil tankers threatened in the Strait of Hormuz has raised the level of concern for countries who use this waterway.
The Advanced Lidar Systems Team (A-LiST) within the Naval Air Warfare Center Aircraft Division (NAWCAD) Electro-Optical (EO) and Special Mission Sensors Division have been hard at work developing advanced laser radar techniques to give unmanned underwater vehicles (UUV) sensing capabilities to detect threats such as mines or other UUVs. Laser-based approaches look to improve stealth while also providing enhanced space and range resolution, high sensitivity to changes in the underwater environment, and fundamentally, wide bandwidth for high speed, wireless data links.
One method, called the Hybrid Lidar-Radar System, uses radar-encoded laser waveforms to “lock on” to a signal reflected from an object and differentiate it from light scattered casually in a specific environment. In comparison, a radar signal would not be able to transmit through water, because its signal would encounter high absorption.
“By encoding the light, we can propagate this radar signal through the water,” said Dr. Linda Mullen, A-LiST Senior Scientific Technology Manager (SSTM). “Then, [we can] take advantage of all the radar processing, radar modulation and demodulation signal processing that has developed over the years for this underwater laser system.”
“We can improve the sensitivity of the laser system to objects that are in very challenging underwater environments,” she explained. “For the warfighter, they would be able to detect objects or threats either at longer standoff ranges or in scenarios where they do not currently have the technology.”
Made from scratch
A-LiST scientists and engineers have also developed a brass board prototype system to test the radar-encoded imaging method in a controlled water tank setting. The results of these tests yielded high-resolution 3-D images in low-visibility, murky waters. Dr. Brandon Cochenour, an engineer at A-LiST, said the facilities allow them to replicate a wide variety of ocean conditions. In a controlled environment, they can evaluate science and prototype systems.
“We’re starting to integrate into these actual autonomous underwater vehicles. We put a sensor into a REMUS 600 autonomous underwater vehicle (AUV) and did some tests out in the bay,” Cochenour continued. “The fleet uses that same vehicle. We’re starting to get into that point where we can integrate our hardware that fits the size, weight and power of these platforms that are used by the fleet.”
Derek Alley has been an electrical engineer at A-LiST for 10 years. He takes the basic research created in the lab, imagines how to make it into a prototype, and ultimately, takes it to the field for testing.
“There’s always a challenge of trying to take the laboratory experiment, which is usually pretty large, and shrinking it down,” Alley said. “What we’re trying to do with these field tests is to get attention from people that have the funds to fund our engineering efforts. We are proving that the technology that we invented works. Now, we need that extra boost to get it to a level that’s fleet ready. We’re trying to demonstrate just that, ‘Hey, look, it works,’ and it works pretty well.”
Hard work has its rewards
A-LiST’s accomplishments have earned them praise. They received the 2018 NAWCAD Section 219 Outstanding Project Award for the overall impact of their project, “Pulse Compression for Enhanced Electro-Optic Identification Performance.”
The team also won the 2018 Assistant Secretary of the Navy for Research, Development and Acquisition Dr. Delores M. Etter Top Scientists and Engineers Award. This award highlights their work in transitioning state-of-the-art underwater laser imaging technology from the laboratory to the field. It is the second time since 2012 the A-LiST has team received this recognition.
A helping hand
It can be expensive and time-consuming to take an idea from a piece of paper to an actual prototype.
It begins with the first basic and applied research proposals and garnering interest in the project through various Navy program offices and the Office of Naval Research (ONR). Partnerships with industry via the SBIR program help mature the hardware needed for advanced prototypes, and collaborations with academia help foster new ideas while also generating a talent pipeline. Then come the basic and applied research awards from the NAWCAD Naval Innovative Science and Engineering (NISE) Program.
A-LiST hopes with all the work placed into this project, someone with the financial means can support their ideas and bring it to fruition.
“I think there’s a lot of value when you grow that organic capability within the lab, because the expertise is here,” Dr. Mullen said. “We can be a sanity check against industry when they propose different things, or we can provide our expertise to help industry and what they’re developing.”
The development of new technologies and collaborations within the fields of industry, academics and other Navy laboratories is vital in keeping the fleet ahead of the curve.