Using Object Oriented Design (OOD) concepts in AMRDEC's Hardware-in-the Loop (HWIL) real-time simulations allows the user to interchange parts of the simulation to meet test requirements. A large-scale three-spectral band simulator connected via a high speed reflective memory ring for time-critical data transfers to PC controllers connected by non real-time Ethernet protocols is used to separate software objects from logical entities close to their respective controlled hardware. Each standalone object does its own dynamic initialization, real-time processing, and end of run processing; therefore it can be easily maintained and updated. A Resource Allocation Program (RAP) is also utilized along with a device table to allocate, organize, and document the communication protocol between the software and hardware components. A GUI display program lists all allocations and deallocations of HWIL memory and hardware resources. This interactive program is also used to clean up defunct allocations of dead processes. Three examples are presented using the OOD and RAP concepts. The first is the control of an ACUTRONICS built three-axis flight table using the same control for calibration and real-time functions. The second is the transportability of a six-degree-of-freedom (6-DOF) simulation from an Onyx residence to a Linux-PC. The third is the replacement of the 6-DOF simulation with a replay program to drive the facility with archived run data for demonstration or analysis purposes.
During the flight of guided submunitions, translation of the missile with respect to the designated aimpoint causes a rotation of the Line-of-Sight (LOS) in inertial space. Large transmit arrays or 5 axis CARCO tables are used to perform True LOS (TLOS) for in-band simulations. Both of these TLOS approaches have cost or fidelity issues for RF seekers. Typically RF Hardware-in-the-Loop (HWIL) simulations of these guided submunitions are mounted on a Three Axes Rotational Flight Simulator (TARFS), which is not capable of translation, and utilize a 2 to 3 seeker beam width transmit array. This necessitates using a Synthetic Line-of-Sight (SLOS) algorithm with the TARFS in order to maintain the proper line-of-sight orientation during all phases of flight which typically includes largely varying LOS motion. This paper presents a simple explanation depicting TLOS and SLOS (TARFS) geometry and the seamless boresight/target SLOS algorithm utilized in AMRDEC's RF4 facility for a test article flight profile. In conclusion this paper will summarize the current state of SLOS algorithms utilized at AMRDEC and challenges and possible solutions envisioned in the near future.