Software architecture for an acquisition tracking and pointing system

This paper describes the embedded systems software design and computer architecture for a High Performance Laser Pointing and Fire Control System (HPFCS). The HPFCS, is a stabilized, high bandwidth target Acquisition, Tracking and laser Pointing system (ATP). The gimbal control, image processing, and mode control is fully digital and is implemented using an integrated TMS320C30 processor, 3 TMS320C80 processors, and a Pentium computer. The C30 gimbal control software consists of over 5,000 lines of code and is written almost exclusively in C. The software features a custom executive with multi-level interrupt control, The main timeline sequence is based on an internal 960Hz-interrupt handler, which phase locks itself to an external 120Hz handler. Over a dozen real-time digital filters, integrators, and compensators are updated during the interrupt timeline. Gimbal positioning is also updated during this period. A high-speed (1.15Mbps) RS-422 port provides external communication with the host. Communications with the host is conducted by using a custom protocol scheme developed to maximize throughput with the HPFCS's DUART buffers and timeline constraints. The image processing subsystems used for target acquisition and tracking consists of 3 PCI based TMS320C80 video processor boards. Each C80 processor handles video processing and tracking functions on a single video source. The image processing tasks performed include clutter rejection, target acquisition, and target tracking. Since each processor has 5 core processors, software tasks are broken down into sub modules to increase parallelism and maximize performance. The C80 software was written in C and Assembly. The custom kernel that executes on the C80 units is based on the TMS320C80 Real-Time Executive, and makes use of hardware level semaphores, messages and port functions. The system also features built in reprogramming software. The reprogramming software allows the systems mission software to be reprogrammed in the field with a laptop. The host software used to control the HPLPS operates on a 200mhz Pentium PC. It runs under Windows 95; and was written using Visual C++. The host control software allows the user to control the HPFCS, and well as providing an interface with Threat Warning and Tracking System. This paper includes a high level overview of the software design including the design process used, Data Flow Analysis, interface, and finally the integration and testing phase.