Establishment Of System Design Requirements Of The DIVAD Visual Fire Control Optics

AbstractThe develornent of the specified optical system parameters is followed ^ron initial constraints, retire­ ments, and scenarios. The process includes consultina with the optical designers to keep the desion practical and performing analyses to define the system confiouration, such as apportioning apertures and spectral bands. Ihe fire control system consists of two. sightinq systems, a search sensor called the Squad Leader's Periscope and a tracking system with -integral laser range finder called the Gunner's Sight. Roth systems are stabilized and have a night vision capability.BackgroundThe DIVAD competition for a mobile armored gun system began in early 1978. By summer of 1930, both competitors had fielded two prototypes. Figure I is a nhoto of the winninrr Ford Aerospace system whlnh is now called the 40mm. DIVAD Gun. The sightline stabilization units were fabricated by F^CC; the laser ran^e- finder was sunnlied by ^ughes Aircraft by modification of an existing system design, and Koll^oraen Corporation designed and fabricated two new separate telescope configurations. All of -the subsystems were specified by FACC to meet the aeneralized reouirements of the contract specifications and scenario implica­ tions. Figure 2 shows the assembled gunsight consisting of a stabilized sight unit (SSU) , the telescope and components of the range finder. Other features include a niaht vision system., a set of projected cues, protection against battlefield lasers and automatic solar protection. A second subsystem used by the squad leader is a panoramic periscope. It is an independent surveillance and acquisition system. Due to its similiarity to the gunsight, it is omitted from further consideration.Figure 1. The 40mm DIVAD gun on the move Figure 2. The contnlete nunsiqht is comprised of the telescope, the laser rangefinder and the stabilized sicrhtIntroductionA brief look is taken at the specification process bv which desiqn reouirenents are formalized and trans­ mitted. This is followed by examples of specific design concerns relative to a visual fire control system. System models and trade studies are presented jcor these concerns.The specification processFigure 3 presents two (2) views that one night hold about the process of generating the design requirements of a system for the fabricator of the syste . In the simple view, the contract requirements ^low down via a specification to a fabricator. In the more complex view, contract reouirements are transformed into a form applicable to the needs of the fabricator. v*io r^ay actually possess the d'esicn knowledge. The system spec­ ifier, typically a systems engineer, identifies constraints, discovers or determines relevant relationships and interfaces, applies his suspicions from ^revious experience and performs the appropriate trade studies using existing or invented models to set the required system design parameters. He ^ust have some sense of the applicable physical laws and have a sense of what can be achieved, such as can a laser share the aperture or how does magnification effect various telescope parameters. After the preliminary specification is set,