Electronic Military & Defense magazine was developed for engineers, program managers, project managers, and those involved in the design and development of electronic and electro-optic systems for military, defense, and aerospace applications.
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Tutorial Practical Electro-Optical Situational Awareness For Armored Vehicles Choosing the appropriate situational awareness system means navigating complexities such as sensor types, mounting locations, video distribution, and more. By Andy Preece T here is growing interest in deploying situational awareness (SA) capability onboard armored vehicles as they are deployed in situations of greater threat, putting crew lives at even greater risk. The primary function of an electro-optical SA system is to provide a constant stream of live video data to the vehicle crew from video sensors mounted on the outside of the vehicle, so that the outside world can be viewed from the relative safety of the vehicle. Achieving this may sound like a relatively simple task, but choosing from the array of different sensor types, sensor mount locations, video compositing, and display systems is a complicated matter. Sensor Type The first step for any systems provider is to select which video sensors to use, how many of them to use, and where to mount them on the vehicle. Sensor selection will also influence the requirements of the additional equipment required to distribute and process the sensor video. With interest in video surveillance growing extensively for more than a decade, a wide selection of different sensor types is now available, from thermal/infrared and low-light sensors to color daylight sensors. More recent developments have seen the advent of hyperspectral sensors capable of generating an image through a wide spectral range. Each sensor type has advantages and disadvantages to the extent that currently no single sensor type can support the complete operating environment required for most military vehicles. For example, infrared cameras offer the ability to see at all times of day — but they generate either a monochrome or false-colored image that may hide useful information available in the visible spectrum. Sensor Format The development of digital sensor technology has been driven by a wide range of industries and has resulted in the development of a number of very different video formats that often require quite different transmission cables. For example, the serial digital interface (SDI) and high-definition SDI (HD-SDI) standards were designed to be used over two-wire coaxial or fiber optic cable, whereas the camera link standard uses a unique miniature delta ribbon (MDR) connector with 26 pins. This range of different video formats and cable options 40 Electronic Military & Defense ■ www.vertmarkets.com/electronics Figure 1: The FRES (Future Rapid Effect System) Scout will support DEF STAN 00-82. FRES is the British Ministry of Defence program to deliver a fleet of more than 4,000 armored fighting vehicles for the British Army. presents a real problem for vehicle SA systems, where the effort and cost of routing video cables through the vehicle are considerable, and therefore the choice of camera format is very important. The more recent development of video cameras that can deliver video content directly over Ethernet cable has been of great interest to vehicle SA systems providers, as it provides a common transmission cable format that can be routed around the vehicle and used to transmit both video and data. This, in turn, has led to the development of military standards that require the use of video-over-Ethernet protocols to deliver video from the sensors to the vehicle crew displays. The U.S. Army's VICTORY architecture requires the use of industry-standard video Ethernet protocols, such as GigE Vision, while the United Kingdom's DEF STAN 00-82 (Figure 1) standard goes further, detailing the use of a uniquely modified version of real-time transport protocol (RTP) and other supporting industry protocols. Both the U.S. and U.K. militaries have indicated that they intend to mandate an Ethernetbased video distribution bus in all their new vehicles. Sensor Location For vehicles that already have remotely operated weapon systems mounted on pan and tilt gimbals (see Figure 2), the simple solution is to retask the weapon system to use its video sensors to provide a 360˚ scan around the vehicle. Although this solution is very cost-effective, it has one big