What is the key phase that military end users and their holographic display development partners point to as the key application? That phase is battlespace visualization. Situational awareness (SA) and establishing a common operating picture (COP) are some of the most critical operational objectives for warfighters today - especially those responsible for making strategic and tactical decisions. Holographic or light field displays represent next generation 3D displays that these military users want. Given the recent Russian invasion of Ukraine, such visualizations may have taken on new urgency.
In many ways the desires of military planners have been shaped by Hollywood movies that show a display volume where those viewers can visualize and interact with various assets and each other. While some of these movie depictions cannot be physically realized, the vision remains a driving force for development.
Battlespaces for any branch of the military are by definition three-dimensional space. Whether it is Navy Seals raiding a compound, an air-to-ground engagement, surface and underwater naval operations or even space-based threat assessment, multiple assets and targets need to be tracked and analyzed in this 3D volume.
In addition, multiple sensors are used in the battlefield such as radar, sonar and visible and infrared cameras. Each of these sensors can provide information that can be valuable in making a decision. Plus, multiple branches of the military can be involved in this battlespace. The challenge is to visualize all this sensor data in a rapidly changing 3D battlespace in such a way as to allow decision makers to make rapid and accurate decisions. These can literally be life changing decisions, which is why military planners are so interested in such capabilities.
The Ukraine situation presents another interesting scenario–tracking Russian and Ukrainian forces and providing intelligence as appropriate. Advanced 3D display systems would offer a clear advantage in conflicts like this.
Holographic displays should enable a more intuitive visualization of the battlespace, say industry officials. The most obvious scenario is visualizing all of the assets and personnel in the battlespace, by their 3D positions and motion vectors. But there are many other data problems that better visuals can help solve. For example, it is often necessary to model the coverage area of military radios to understand when signals will be blocked and/or reflected off of surfaces. With a holographic display, a field operator can quickly see if he can communicate with another person or asset.
For naval operations, it takes years of training to understand sonar signals and learn how to mentally map underwater objects in 3D space. Turning such signals into a visual 3D volume representation reduces the cognitive load and allows less trained operators to have the same skill sets as experienced ones.
In air operations, telemetry data may show the altitude and directional vector of an asset, but it can be hard to visualize if it is ascending or descending and at what rate. Again, a 3D holographic display makes such information more intuitively obvious.
Post engagement reviews of Special Forces operations often found that a poor spatial understanding of the situation led to failures or compromises in the mission. As a result, decision makers need better spatial visualization tools.
Research into advanced 3D display has been going on for over 20 years. One of the leading organizations that directed this research was the Air Force Research Lab out of Wright Patterson Air Force Base in Ohio. This group, led by Darryl Hopper, has offered Small Business Innovation Research awards to fund many types of display development.
Some of these developments have gone to Phase 2 awards which produced working prototypes that were then subsequently evaluated by various Government or military agencies. But this is very difficult technology to develop, so no systems have been rolled out to date.
While AR and VR headsets are being evaluated as well to address some of these needs, there is a clear preference to not have to wear a headset of any kind, as this interferes with external communication with other decision makers.
Advanced holographic display can come in multiple form factors. The “sand table” implementation is most often desired for multi-person collaboration, ideally with viewers able to see and interact with images all the way around the sand table.
Another popular implementation is a monitor for 1-3 people. In September 2021, Kongsberg Geospatial said they are working to develop a monitor-type display solution to combine passive sonar data with three-dimensional bathymetric data to create an accurate sensor picture that can be used to locate and identify possible undersea threats.
But there are many challenges to improving the fidelity of their light field/holographic displays. Some technical approaches rely on conventional microdisplay technologies coupled to lens arrays to create directional rays. Developers here see a need for pixel density to increase considerably, for the light emitting angles to narrow and better interconnection methods to drive these panels. The compute power is also significant so new purpose-built, multi-view rendering architectures should be developed.
Others acknowledge that high fidelity holographic displays can be created using current technology, but these existing photonic technologies will always face cost and form factor challenges.
While holographic display developers are optimistic about the development of display technology, they likewise think the fledgling industry will need support to succeed.
Developers that have relied on SBIRs (Small Business Innovation Research) funding don’t think this will be enough to really move the industry forward. Larger government and industry led efforts may be needed to focus on the specific challenges of holographic and light-field displays if we want to accelerate development.
Other developers believe it will be vital to leverage developments in the consumer electronics space to make these displays perform better and cost less. As an example, they point to mobile phones and VR as models for development. Over time, each has added more and more features and functionality while bring down prices.
What will military holographic displays look like in 10 years? Some think we will see deployed battlespace sand tables with a field of view of 100-to 120-degrees, HD resolution and several feet of depth volume by generating 10 billion plus rays.
Other think these sand tables will be here as well, but not yet operational with the military still doing human factors testing to better determine how best to visualize the battlespace and to quantify the collaborative and cognitive benefits it delivers. This is a necessary step before actual deployment in live military activities.
It seems clear that there is wide interest in advanced 3D displays in the military and government agencies. But there are also many other uses for these holographic and light-field displays, so consumer and commercial activities may be enough to help with the military advancements. If not, government agencies and the armed services may have to step up to further fund or speed up development for their more urgent use cases.