Future Use Of Electro-Optical Sensors By The Defense Industry

By John Oncea, Editor

Electro-optical sensors are indispensable tools for modern military operations. As technology advances, these sensors will continue to evolve, providing enhanced situational awareness and lethality to military forces.

Electro-optical sensors, sometimes called electro-optical infrared sensors, are electronic detectors that convert light or changes in light into electronic signals. They can detect electromagnetic radiation from infrared to ultraviolet using a combination of electronics and optics to identify, track, and detect objects in the infrared spectrum and are used in applications such as communication, navigation, imaging, and monitoring.

An electro-optical (EO) sensor “is typically part of a bigger system that brings together a source of light, a measuring device, and the optical sensor; with the latter connected to an electrical trigger,” YoungWonks explains. “The trigger then responds to a change in the signal within the light sensor and the optical sensor tracks and measures the changes from one or many light beams.”

The light sensor serves as a photoelectric trigger that either increases or decreases the electrical output. The optical switch – an optoelectronic device that can be integrated with integrated or discrete microelectronic circuits – allows signals in optical fibers or integrated optical circuits to be selectively switched from one circuit to another. Optical switches can operate through mechanical means or electro-optic effects, magneto-optic effects, or other methods.

While there are many kinds of OEs out there, the four most common types are photoconductive devices, photovoltaics, photodiodes, and phototransistors. “In addition to the above types, we look at the optical sensor types based on their different characteristics,” writes YoungWonks. “These would be point sensors and distributed sensors; extrinsic, intrinsic, and through-beam sensors, diffuse reflective sensors, and retro-reflective sensors.”

Current Uses Of Electro-Optical Sensors In Defense

EO sensors can be used anytime light has to be converted into energy with smartphones, computers, and smartwatches being some of the most common examples of devices utilizing this technology. EOs are used by industries as diverse as energy, transportation, and medicine.

They are also used by the defense sector where they are found in the infrared systems of unmanned aerial vehicles. “Since they span both visible and infrared wavelengths,” YoungWonks writes, “EO systems also use thermal imaging and go on to offer complete and even real-time situational awareness, including night-vision and in low light conditions.”

EOs play a crucial role in technologies beyond night vision including soil disturbance detection (indicating potential roadside bombs), missile launch detection, and locating small boats at sea. Additional ways defense is using EOs include:

• Surveillance and Reconnaissance: EOs are used extensively for gathering intelligence, monitoring enemy movements, and conducting reconnaissance missions. They provide real-time imagery of the battlefield, enabling commanders to make informed decisions.
• Target Acquisition and Tracking: EOs help military forces locate and track targets, including vehicles, personnel, and infrastructure. They are integrated into various platforms such as unmanned aerial vehicles (UAVs), helicopters, and ground-based surveillance systems.
• Precision Guided Munitions: EOs play a critical role in guiding precision munitions to their targets with high accuracy. Laser-guided bombs and missiles use laser designators to mark targets, while imaging sensors provide feedback for terminal guidance.
• Navigation and Situational Awareness: In addition to targeting, EOs contribute to navigation and situational awareness for military platforms. They help pilots and vehicle operators navigate terrain, avoid obstacles, and detect threats.

Future Uses Of Electro-Optical Sensors In Defense

While the U.S. Army has long claimed to “own the night” thanks to EOs – a claim that may no longer be true, according to Modern War Institute – advancements are on the horizon that may revolutionize their capabilities. Future EO systems are likely to incorporate multiple sensors, including imaging, infrared, and laser sensors, to provide enhanced capabilities such as improved target detection and discrimination.

Researchers are working on extending the range of EOs, allowing them to detect targets from even greater distances, as well as focusing on shrinking pixel size. Smaller pixels enable higher-resolution images, providing better situational awareness and long-range performance. Infrared search-and-track systems, in particular, benefit from this advancement.

Researchers are also working to reduce the size, weight, and power consumption (SWaP) of EOs to allow for easier integration into various platforms including drones and soldier-worn devices. In addition, they are exploring the use of new materials that will enable sensing at higher temperatures, further expanding operational capabilities.

Sensor and processor architectures are becoming more adaptable, following industry standards and allowing for rapid technology updates. Also, by blending different spectral sensing techniques, EOs can provide more comprehensive information about the environment in which the devices that use them are being deployed.

“Add in advanced processing techniques such as AI, machine learning, neomorphic processing, standards-based rapidly adaptable embedded computing architectures, and 3DHI, and electro-optical sensors designers can pull out more useful information from digital imagery than ever before,” writes Military Aerospace Electronics.

“Signal processing, from a modality standpoint, helps to identify and recognize the target,” says John Baylouny, chief operating officer of Leonardo DRS. “It can help fuse the information, in applications such as radar and passive sensing in SIGINT [signals intelligence] and COMINT [communications intelligence]. We want to recognize the signal not for intelligence, but for understanding.”

Finally, Artificial Intelligence And Machine Learning

Recent advancements in EO technology have been revolutionary, especially with the inclusion of artificial intelligence (AI) and machine learning. These technologies not only enhance the precision of images, expand the range, and enable the detection of elusive objects, but they can also assist the sensors in identifying critical information.

“The operator doesn't need to have constant eyes on target,” says Aaron Maestas, technical director for electro-optical and infrared solutions at RTX Raytheon. According to Military Aerospace Electronics, “AI helps to find conditions that are different than normal. It can say with 80 percent certainty that the target is a tank, a SAM site, or another kind of threat.

“For the same token, AI also can help detect targets that might not be visible to the human eye, such as a small boat on a vast ocean. ‘The ocean is enormous, and people do not get a sense for how large it is,’ Maestas says. ‘With AI we can scan all the visible ocean surface and find objects that are not waves, whether it is a fishing trawler, commercial shipping vessel, or a navy destroyer.’”

EOs will continue to play a key role in enabling autonomy in military systems, allowing unmanned platforms to detect, track, and engage targets without human intervention. As they become more prevalent in military operations, adversaries may develop countermeasures to evade detection and targeting. Therefore, there will be a continued emphasis on developing advanced sensor technologies and tactics to maintain superiority on the battlefield.