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DOI: 10.2514/1.32531 The Federal Aviation Administration's augmentation to the global positioning system for civil aviation is called the wide area augmentation system. This paper introduces the wide area augmentation system-based flight inspection system. This system is better optimized than the current flight inspection systems in terms of accuracy, cost, and efficiency. Although they meet the Federal Aviation Administration's flight inspection system accuracy requirements, the current flight inspection systems are either higher cost or less efficient. The innovative use of the wide area augmentation system with a radar altimeter and a television positioning system without a requirement for an inertial navigator makes it possible for the wide area augmentation system-based flight inspection system to have low cost and high efficiency in flight inspection for instrument landing system calibration. The wide area augmentation system-based flight inspection system meets the Federal Aviation Administration's accuracy requirements for CAT III ILS calibration and also provides firm integrity algorithms. The performance of the wide area augmentation system-based flight inspection system is confirmed with tests using flight data taken in collaboration with the Federal Aviation Administration.

This paper presents an algorithm for calibrating strapdown magnetometers in the magnetic field domain. In contrast to the traditional method of compass swinging, which computes a series of heading correction parameters and thus is limited to use with two-axis systems, this algorithm estimates magnetometer output errors directly. Therefore, this new algorithm can be used to calibrate a full three-axis magnetometer triad. The calibration algorithm uses an iterated, batch least-squares estimator that is initialized using a two-step nonlinear estimator. The algorithm is simulated to validate convergence characteristics and further validated on experimental data collected using a magnetometer triad. It is shown that the post-calibration residuals are small and result in a system with heading errors on the order of 1 to 2 degrees. DOI: 10.1061/(ASCE)0893-1321(2006)19:2(87) CE Database subject headings: Calibration; Magnetic fields; Algorithms; Aerospace engineering.

The design of inexpensive multi-sensor attitude determination systems is discussed. The systems discussed fuse information from a triad of solid state rate gyros with an aiding system mechanized using GPS or magnetometers and accelerometers. Euler angle and quaternion-based sensor fusion algorithms are developed. Methods for gain scheduling and estimator pole placement are presented. Using simulation and flight test results, it is shown that quaternion-based algorithms simplify gain scheduling and improve transient response.

Research into the use of cylinder pressure measurements from reciprocating internal combustion engines for real time automotive engine control has been investigated for the last 20 years. The measurement has been investigated for spark timing, fuel-air ratio control, charge temperature measurements, and misfire detection. The cost of the sensors has inhibited widespread use in production vehicles; however, it was introduced in domestic Japanese production for spark control five years ago. Its use for misfire detection is also being actively considered.

A unaugmented Global Positioning System (GPS)-based flight inspection system (FIS) that performs airborne inspection of the instrument landing system (ILS) is introduced. This novel system relies on a TV positioning system (TVPS) that measures the horizontal position over the runway threshold and a radar altimeter (RA) to determine a reference point that is able to remove the GPS biases. Because of the near-real-time nature of flight inspection, it is possible to reconstruct an accurate approach trajectory even though the reference point occurs after the completion of the trajectory. The precise relative positioning (PRP) algorithm is applied to achieve the desired results. It includes a first-order fit to the ionospheric error, based on code and carrier measurements, that enables a significant reduction in this error source. This system has an autonomous integrity feature, called FIS-RAIM (receiver autonomous integrity monitoring), that is equipped in this system to protect against GPS satellite failures that may cause significant positioning errors. The FIS-RAIM is specifically designed for a flight inspection problem, and much of its detail is also described. Experimental flight tests strongly suggest that the system architecture and algorithm could meet FIS accuracy requirements for CAT III ILS with better performance than current flight inspection systems in terms of cost and efficiency. The system is not dependent on any GPS augmentation system; therefore the unaugmented GPS-based FIS provides low cost and high efficiency with worldwide availability. [ABSTRACT FROM AUTHOR]

The design of inexpensive multi-sensor attitude determination systems is discussed. The systems discussed fuse information from a triad of solid state rate gyros with an aiding system mechanized using GPS or magnetometers and accelerometers. Euler angle and quaternion-based sensor fusion algorithms are developed. Methods for gain scheduling and estimator pole placement are presented. Using simulation and flight test results, it is shown that quaternion-based algorithms simplify gain scheduling and improve transient response. [ABSTRACT FROM AUTHOR]