DAHLGREN, Va. –
A blending of the past and present offered the perfect environment for indoor laser testing at Naval Surface Warfare Center Dahlgren Division (NSWCDD). In the mid-1940s, the Department of the Navy constructed an above-ground, enclosed multi-compartment concrete tunnel measuring 117 meters in length that supported the former site of an outdoor live-fire range. The structure provided a way to transport personnel and supplies down the tunnel to the target butts that supported the live-fire range. The underground rooms also provided a storage area for equipment.
Over time, the buildings that adjoined the tunnel were demolished and replaced with the current NSWCDD buildings, however they are separate from the tunnel. Today, known as the laser tunnel, it serves a slightly different purpose than in its past life. After undergoing several renovations to add buildings to each end and seal up the basement level storage areas, the tunnel is primarily utilized for test and evaluation events developing laser weapon system technology.
The Integrated Engagement Systems Department oversees the management and maintenance of the tunnel and works closely with various departments across the warfare center division to provide a safe and secure test environment for laser systems testing.
During a three-day data collection and evaluation event in mid-May, the Integrated Clip-on Advanced Targeting Sight Dual Band Imager (ICATS DBI) team as well as personnel from the Laser Weapon System Technology and Lethality Branch – within the Integrated Engagement Systems Department – worked collectively to bring about a successful event for a prototype sensor system supporting the Office of Naval Research Code 35 Maritime Fires (ONR35).
The ICATS DBI team consists of team members who support the Precision Sensing Branch within the Electromagnetic and Sensor Systems Department and supports initiatives relating to laser data collection for laser weapons systems.
The team identified ONR requirements and established procedures to execute the test and evaluate the laser sensor component.
When the ICATS DBI team needed a secured, controllable space long enough to conduct the testing of the releasable test dewar (RTD) system, they reached out to Senior Test and Evaluation Lead Michael Richardson, who provided support in scheduling, ensuring safety procedures were followed and helping the team with meeting technical requirements for facility use.
“I was contacted about being able to use the laser tunnel. We made arrangements for the team to come and tour the facility to see if it would meet their needs,” said Richardson. “Because of the dimensions of the tunnel – 117 meters long by just over 1 meter by about 2 meters tall with 8 to 12-inch thick reinforced concrete walls – it worked out beautifully for them.”
According to ICATS DBI Project Lead Alfred Ernst, the RTD is a “specific piece of lab hardware that houses a focal plane array, lens and other supporting electronics to do infrared imaging.” Ernst discussed the data collection event and the opportunity to utilize a space that proved optimal and efficient. “The RTD is a modular system built by our external partners and integrates both imaging capabilities and laser detection,” said Ernst. “We wanted to test the sensor itself and determine whether it was capable of detecting certain types of battlefield lasers and so this was a controlled environment where we could test in. There’s different classifications of lasers and a lot of technical restrictions on where you can shoot those lasers, so our own optics lab wasn’t an ideal space. The tunnel was very useful in that way where you can shoot higher powered lasers, following all safety procedures in an enclosed, secured area.”
In order to collect the data the team was after, they integrated a laser detector with the RTD. This specific hardware allows for the detention of reflective laser pulses and provides laser decoding. Various reflective targets situated at different distance intervals were used to determine the laser sensor systems’ capabilities, exercising the event detector against the systems hardware and software components. The event also established laser testing procedures with the RTD system.
The ICATS DBI team supports test and evaluation events involving various types of optical measurements and evaluations against requirements to develop and deliver top-performing products to the Marine Corps. “We help to evaluate the performance of different iterations of DBI sensor prototypes,” Ernst said. “The laser data collection event is one example of that, of testing a capability to do certain types of laser detection with the sensor in an indoor, controlled environment, and that is just part of the larger effort of doing our optical test and evaluation.”
In the coming months, the ICATS DBI team expect to host a demonstration of the laser see-spot detection and decoding at the Fort A.P. Hill laser range for stakeholders and ONR35.