In this paper, the authors propose to introduce and describe a newly developed precise tightly-coupled integrated navigation system. The performed experiments with the purpose of evaluating the system performance are shown. A complete description of the integrated navigation system hardware, including calibration details, and software, with filtering aspects, is given. The main features of the integrated navigation system include the simple conversion from loosely-coupled to tightly-coupled integration, and flexibility to the available GPS observables. The observables can range from pseudoranges to the more challenging dual frequency carrier phases, where integer ambiguity resolution is needed and included. Performance evaluation and quantification of the navigation system hardware and algorithms are done through the presentation of results from static and flight tests. The flight test corroborates that improvements had to be made in the developed acquisition system block of the integrated navigation system. Therefore, to evaluate the developed and implemented algorithms, inertial data from a different inertial measurement unit had to be used. The obtained attitude results are compared against a GPS attitude reference system available during the flight tests. Copyright © 2005 by Jose Lorga.