Security and Defense

Applications in (civil) security and defense always require a maximum of complexity and reliability. The business unit Space and Security of Fraunhofer IMS counters these steadily growing demands and expectations of its customers with state of the art and innovative MEMS technologies (“micro-electro-mechanical systems“) resulting in flexible, future-proof and reliable customer applications with focus on optical sensors for observation and surveillance of critical infrastructures.

As one of those cutting-edge and forward-looking technologies within the business unit Space and Security of Fraunhofer IMS, the IRFPA technology based on microbolometers allows for passive observation, detection and surveillance of people or objects by means of uncooled IR imaging methods. In this context, passive advantageously means that no active illumination of the scenery is required since, according to Planck’s law, people or objects emit IR radiation themselves.

Depending on individual, customer-specific demands, either MWIR („mid wave infrared“) with wavelengths ranging from 3 µm to 5 µm or LWIR („long wave infrared“) with wavelengths ranging from 8 µm to 14 µm can be chosen as the wavelength range of choice for applications in (civil) security and defense.

Optical sensors for (civil) security

In this regard, MWIR sensitive IRFPA sensors are suitable for detection and surveillance of so-called »hot sources«. The latter exhibit temperatures of several hundred Kelvin and appear in sensing of gases by means of imaging methods or in firefighting. The business unit Space and Security of Fraunhofer IMS is technologically capable of designing their IRFPA sensors that way, that not only sensing of gases by means of imaging methods, but also a detection of the respective spectral lines of different gases becomes possible, depending on the individual, customer-specific demands.

In the specific case of fire detection and firefighting, the IRFPA technology provides not only a visualization of the fire source itself with high contrast as compared to the visible light spectrum, but also a spectral detection of hazardous gases, such as CO (Carbon monoxide) and O₃ (Ozone), or highly inflammable gases, such as CH₄ (Methane) and NH₃ (Ammonia), thus allowing for an early and secure assessment and evaluation of critical and dangerous situations for various applications in (civil) security.

Optical sensors for detection of people

In contrast, IRFPA sensors optimized for LWIR are highly sensitive to human IR radiation and are mainly used for a reliable detection and surveillance of people under weak visibility conditions, such as at night, in fog, smog or smoke. The latter is not only relevant for customer applications with police or military background, but also for use in civil security, such as for mountain and sea rescue or traffic safety. As an additional application in (civil) security, the IRFPA technology provided by the business unit Space and Security of Fraunhofer IMS allows for a contactless measurement of human body temperature with the latter being installed at access controls of critical or highly frequented infrastructures.

Assuming no weak visibility conditions, but objects moving with high speed are the main concern for the detection of objects, the innovative BSI SPAD („backside illuminated single photon avalanche diode“) technology of Fraunhofer IMS may be the technology of choice. BSI SPAD arrays serve the customers of the business unit Space and Security as highly sensitive detectors in LiDAR (“light detection and ranging“) sensors for a three-dimensional detection of the environment or objects moving with high speed.