SAASM Rockwell Collins' Next Generation GPS Receiver Design

Rockwell Collins has leveraged its position as a primary military GPS supplier by developing a new, low cost version of SAASM for use in multiple applications. The Rockwell Collins SAASM has been designed as a common module that can be used to support all internal SAASM applications. Its architecture provides an advanced set of core functions while at the same time supporting easy integration into various applications. This paper presents the architecture, features, and status of the Rockwell Collins SAASM and describes three applications that incorporate this module, specifically, NavStrike, the SSI receiver, and GEM V™.“NavStrike” is a very small, high A/J, high G, fast DY, receiver specifically designed for Precision Guided Munitions (PGM) applications. Through the use of a proprietary technique, this receiver provides unclassified GPS measurement data for use in tightly coupled integrations. Position Velocity and Time (PVT) outputs are also available. This SAASM based receiver takes advantage of the many features provided by the core SAASM module including black key and fast acquisition support. NavStrike uses special features such as a high-speed serial interface, a unique frequency standard and a clock calibration mode to perform fast DY acquisitions after up to 20 years of storage. A Small Serial Interface (SSI) product is being developed using the common SAASM module. Among the users of this GPS technology are the ground (low dynamics, minimal environmental) applications that embed the GPS directly within their own equipment. The PVT data provided by the SSI receiver can be easily integrated with the host system providing additional navigation performance with minimal space and cost impacts. This SSI module, which uses the new GRAM SSI standard, is being designed to be a seamless drop in replacement of existing ground applications embedded receivers. GEM V™ is the most recent member of the GEM™ product line. The GPS Embedded Module (GEM™) receivers are designed for high performance, high dynamic embedded applications. GEM V™ is a SAASM-based module that features the high AJ characteristics and Direct Y capabilities of previous GEM™ products. The GEM V™ is integrated with a host system through a dual port RAM or a serial port (RS-422) interface. Once integrated, the GEM™ can perform as a fully functional guidance system, as a PVT engine, or as a GPS measurement sensor.