Achieving modularity with tightly-coupled GPS/INS

Addresses a problem of GPS/INS (Global Positioning System/inertial navigation system) integration wherein the conflicting goals of modularity and tight coupling are both sought. The advantages to be gained from modularity are described. The performance advantages of tight coupling are reviewed, and it is explained why it is so difficult to achieve both modularity and tight coupling in the same architecture. A candidate is then presented and evaluated relative to the stated goals. Key aspects of its operation and timing structure are described, including difficulties the architecture overcomes such as discontinuous INS aiding of receiver tracking loops as the system transitions through various modes. Computational requirements and throughput or the integration processor are discussed. The problem of testing individual components is considered where those components are normally expected to operate only when fully integrated. The author deals primarily with low-cost applications such as remotely piloted vehicles and tactical munitions where tight coupling and modularity are especially valuable.>