Flight Test Data Analysis Research Articles

The angle of attack and side-slip angle estimation for civil aircraft

The angle of attack and side-slip angle are two important flight parameters that directly affect the flight safety of civil aircraft. This paper studies the estimation method for the angle of attack and side-slip angle according to air-data system, inertial navigation system, and aircraft aerodynamic data to improve flight safety under the condition of icing, failures, and improper maintenance. Flight tests show that the proposed estimation method is feasible, reliable, and has better accuracy. Furthermore, flight test data analysis shows that the angle of attack estimation error is within 1 degree, and the side-slip angle estimation error is within 1.5 degrees which can meet the requirements of engineering application.

Flight-Test Validation of a Takeoff Performance Uncertainty Model

A Monte Carlo model designed for fixed-wing aircraft takeoff performance uncertainty quantification is benchmarked. The uses of an efficient takeoff simulator of this type range from rapid design variable and constraint sensitivity studies and large-scale conceptual level analyses to operational performance planning and real-time anomaly detection. The accuracy of the model is assessed against high-resolution flight-test data obtained through a campaign consisting of eight takeoffs flown with a specially instrumented commuter category transport aircraft: a BAe Jetstream Series 3100 twin turboprop. On all but one of the takeoffs, a close agreement is seen in terms of the takeoff distance, as predicted vs as observed, at the point of passing a 35 ft screen height; for the outlier, evidence of a sudden change in wind speed is presented as the probable cause of the discrepancy. Such studies are subject to many other sources of error and uncertainty, which are inherent in both flight-test data analysis and simulation, stemming from the highly dynamic and complex nature of this phase of the flight. The analysis presented also proposes to be a template for dealing with these issues, in a way that is applicable to other benchmarking studies.

Aplikasi Filter KALMAN Pada Gerak Matra Longitudinal Pesawat Udara Boeing-747

Many of aircraft perfonnance became from the stability and control of flight test data analysis. This paper introduces the Kalman Filter analysis on the Boeing 747 data aircraft to knawn the output response if disturbance (as turbulence or noise) absence on the closed loop control system. We found the output response of the plant on algorithm Kalman Filter tend to the unstable conditions, but we don't knaw the response of the whole of closed loop diagram block control system of Boeing 747 aircraft.Keywords : aircraft control system, turbulence, Kalman Filter

Effects of Attitude on HIFiRE-5b Boundary-Layer Transition

HIFiRE-5 is a hypersonic flight-test experiment designed to investigate the aerothermodynamics of a three-dimensional geometry. The vehicle is an elliptic cone with a 2:1 aspect ratio and 2.5 mm nose radius. The HIFiRE-5b achieved a Mach number of 7.7 to 7.9 and freestream unit Reynolds number of to during descent. Heat flux was calculated from thermocouple pairs, and boundary-layer transition locations were identified from these heating rates. A multilobed transition front was observed; it is suspected that a different mechanism is responsible for each of these lobes. The first round of flight-test data analysis did not control for attitude variation, resulting in oscillating heat-flux rates. The current work subsamples the data based on angle of attack and yaw, enabling a more precise investigation of other relevant variables. Regions of the flowfield especially sensitive to attitude variation can be better analyzed. The heating rate at the leading edge exhibits the expected dependence on yaw angle and insensitivity to angle of attack. Data from the crossflow-dominated portion of the flowfield show the region’s sensitivity to angle of attack and dependence on yaw. Transition near the centerline exhibited a small dependence on angle of attack, but a large effect from yaw.

Design and Performance Evaluation of Propeller for Solar-Powered High-Altitude Long-Endurance Unmanned Aerial Vehicle

Design, wind tunnel test, computational fluid dynamics (CFD) analysis, and flight test data analysis are conducted for the propeller of EAV-3, which is a solar-powered high-altitude long-endurance unmanned aerial vehicle developed by Korea Aerospace Research Institute. The blade element momentum theory, in conjunction with minimum induced loss, is used as a basic design method. Airfoil data are obtained from CFD analysis, which takes into account the low Reynolds number effect. The response surface is evaluated for design variables by using design of experiment and kriging metamodel. The optimization is based on desirability function. A wind tunnel test is conducted on the designed propeller. Numerical analyses are performed by using a commercial CFD code, and results are compared with those obtained from the design code and wind tunnel test data. Flight test data are analyzed based on several approximations and assumptions. The propeller performance is in good agreement with the numerical and measurement data in terms of tendency and behavior. The comparison of data confirms that the design method, wind tunnel test, and CFD analysis used in this study are practically useful and valid for the development of a high-altitude propeller.

The Comparison Of In-Flight Pitot Static Calibration Method By Using Radio Altimeter As Reference with GPS and Tower Fly By Methods On CN235-100 MPA

The new proposed In-Flight Pitot Static Calibration Method has been carried out during Development and Qualification of CN235-100 MPA (Military Patrol Aircraft). This method is expected to reduce flight hours, less human resources required, no additional special equipment, simple analysis calculation and finally by using this method it is expected to automatically minimized operational cost. At The Indonesian Aerospace (IAe) Flight Test Center Division, the development and updating of new flight test technique and data analysis method as specially for flight physics test subject are still continued to be developed as long as it safety for flight and give additional value for the industrial side. More than 30 years, Flight Test Data Engineers at The Flight Test center Division work together with the Air Crew (Test Pilots, Co-Pilots, and Flight Test Engineers) to execute the flight test activity with standard procedure for both the existance or development test techniques and test data analysis. In this paper the approximation of mathematical model, data reduction and flight test technique of The In-Flight Pitot Static Calibration by using Radio Altimeter as reference will be described and the test results had been compared with another methods ie. By using Global Position System (GPS) and the traditional method (Tower Fly By Method) which were used previously during this Flight Test Program (Ref. [10]). The flight test data case are using CN235-100 MPA flight test data during development and Qualification Flight Test Program at Cazaux Airport, France, in June-November 2009 (Ref. [2]).

Analysis of the Aircraft Motion at the Overcritical Angles of Attack: Errors of On-Board Measurements and Simulation of the Deviated Thrust Vector

The article deals with the problems of the flight test data analysis concerning the flights at higher then critical angles of attack in order to improve the mathematical model of an aircraft's motion. The paper presents a technique for validation and correction of the on-board measurements for this type of motion. Regarding the use of the vector control during such maneuvers, the article considers the mathematical model of the forces and torques generated by the thrust vectoring. Examples of the data processing of the modern maneuverable aircraft's flight tests are presented to confirm the efficiency of the proposed models and methods. The validation of the on-board measurements, above all, the aerometric measurements, is based on the equations of the aircraft spatial motion. It is assumed that the correct values of the motion parameters must satisfy the system of the nonlinear differential equations known from the flight dynamics. This approach has already proved its efficiency in the analysis of the flight data in the operational range of the angles of attack. The signals obtained through the simulation are used to correct the measurements in case of errors. The article presents examples of detection and correction of errors in the measurement channels for a true airspeed and angle of attack. This paper also proposes two versions of the model capable of calculation the projections of the forces and torques on the aircraft principal axes. The first version is derived from the evident geometrical considerations, the second one is based on Rodrigues' vector rotation formula known in the theoretical mechanics. A numerical comparison confirmed correctness of both obtained models. These models were also verified by processing of the flight tests data.

Flight Test Data Analysis of Hybrid Vertical Take-off and Landing Unmanned Aerial Vehicle

Abstract —A Hybrid Unmanned Aerial Vehicle (UAV) has both advantages of multirotor and fixed-wing UAV. This unique design leads to a more complicated airframe and control design compared to those of a conventional drone. Integrating two platform of UAV (mutirotor and fixed-wing) also requires carefully consideration to safely operate this hybrid UAV. This paper discussed the flight scenario that includes flight modes and parameters to be determined before flight. This leads to the development of the flight procedure as an important prerequisite for a successful flight.

Algorithms for Validation of the Flight Data and Evaluation of the Nonlinearities of the Aerodynamic Coefficients of the Aircraft

He system identification methods make an important part of the flight test data analysis. Due to these methods accurate aircraft parameter estimations can be obtained, which meet the requirements of numerous applications, such as simulators and flight control systems design, aircraft modernization, etc. The aircraft parameter identification, when applied to the processing of the actual flight test data, faces the following principal problems: inevitable differences between a physical object and the adopted mathematical models; an essential incorrectness of the identification problem, since it belongs to the class of the inverted problems of dynamics. The presented techniques are intended to overcome those difficulties, using a system approach. That means that the identification problem is treated as an integral multistage system, designed on certain basic principles. These principles are the following: every stage includes a verification procedure; a decomposition of the general problem into minor subproblems; a systematic search for all the useful information in the relevant disciplines; an important role of a human operator. The article presents an algorithmic and methodological support for monitoring of the correctness of the airborne measurements and estimation of the aerodynamic nonlinearities for identification of the aerodynamic coefficients of the aircraft according to flights test. The paper also presents numerous examples of the practical applications of the considered methods and algorithms in the process of the parameters identification of the mathematical models of certain modern aircraft, using the flight test data. The authors believe that the choice of those examples would be helpful for understanding of the typical problems of the aircraft parameter identification.

A heuristic reference recursive recipe for adaptively tuning the Kalman filter statistics part-1: formulation and simulation studies

Since the innovation of the ubiquitous Kalman filter more than five decades back it is well known that to obtain the best possible estimates the tuning of its statistics \({\mathbf{X}}_{\mathbf{0}}\), \({\mathbf{P}}_{\mathbf{0}}\), \(\Theta \), R and Q namely initial state and covariance, unknown parameters, and the measurement and state noise covariances is very crucial. The manual and other approaches have not matured to a routine approach applicable for any general problem. The present reference recursive recipe (RRR) utilizes the prior, posterior, and smoothed state estimates as well as their covariances to balance the state and measurement equations and thus form generalized cost functions. The filter covariance at the end of each pass is heuristically scaled up by the number of data points and further trimmed to provide the \({\mathbf{P}}_{\mathbf{0}}\) for subsequent passes. The importance of \({\mathbf{P}}_{\mathbf{0}}\) as the probability matching prior between the frequentist approach via optimization and the Bayesian approach of the Kalman filter is stressed. A simultaneous and proper choice for Q and R based on the filter sample statistics and other covariances leads to a stable filter operation after a few iterations. A typical simulation study of a spring, mass and damper system with a weak nonlinear spring constant by RRR shows it to be better than earlier techniques. Part-2 of the paper further consolidates the present approach based on an analysis of real flight test data.

Investigation of Missile Control Surface Effects on F-16 Limit-Cycle Oscillation

Tactical aircraft with thin wings and heavy external wing stores are susceptible to aeroelastic limit-cycle oscillations. This investigation applies both frequency-domain and time-domain solutions using aeroelastic computational models to predict limit-cycle oscillation onset, frequency, and amplitude on an F-16. The test configuration uses missile shapes with reconfigurable aerodynamic and mass properties. Statistical analysis of flight-test results identifies significant experimental variables of missile aerodynamic configuration, flight condition, and aircraft fuel state. Furthermore, statistical analysis permits the normalization of flight-test results for direct comparison to aeroelastic models. Results of the comparison show that flight-test data analysis mostly supports the prediction trends, but the magnitude of the aerodynamic effects due to the canards and fins is much less significant in the test data.

Frequency and damping identification in flutter flight testing using singular value decomposition and QR factorization

A new method, based on singular value decomposition and QR factorization, has been developed and applied to the analysis of F-18 flutter flight test data. The method is capable of identifying the frequency and damping of the critical aircraft modes, those responsible for the flutter phenomenon. The procedure relies on the capability of singular value decomposition for the analysis, modeling, and prediction of data series with periodic features and also on its power to identify matrix rank. The analysis of simulated and real flutter flight test data demonstrates the effectiveness, robustness, noise-immunity, and the capability for automation of the method proposed under specific conditions.

Motion error analysis of the 3D coordinates of airborne lidar for typical terrains

A motion error model of 3D coordinates is established and the impact on coordinate errors caused by the non-ideal movement of the airborne platform is analyzed. The simulation results of the model show that when the lidar system operates at high altitude, the influence on the positioning errors derived from laser point cloud spacing is small. For the model the positioning errors obey simple harmonic vibration whose amplitude envelope gradually reduces with the increase of the vibration frequency. When the vibration period number is larger than 50, the coordinate errors are almost uncorrelated with time. The elevation error is less than the plane error and in the plane the error in the scanning direction is less than the error in the flight direction. Through the analysis of flight test data, the conclusion is verified.

A Response Surface Methodology for Modeling Time Series Response Data

This article introduces extensions to classical response surface methods specifically for modeling and exploiting time series response data such as found in aircraft flight test. Classical response surface methods focus on the analysis of discrete response data. In some complex, nonlinear systems, analysts are concerned with the behavior of time series response data. To date, there does not appear to be any formal methods for examining and exploiting these data within a response surface framework. Thus, a mathematical framework is defined and then demonstrated through a sample analysis of empirical flight test data. Copyright © 2012 John Wiley & Sons, Ltd.

Earth-Surface Multipath Detection and Error Modeling for Aircraft GPS Receivers

: For aircraft precision approach operations, Earth-surface multipath observed by an aircraft GPS antenna aegraaes tne accuracy of pseudorange measurement. Uf particular concern are stabuized approaches over water where the water reflection of the GPS signal could generate sustained multipath error. A novel multi-path detection method is introduced in this work. It provides accurate estimates of multipath strength and fading frequency using a software-defined radio GPS receiver and radio frequency data collected from a top-mounted antenna. Combined with analysis of flight-test data collected from both the top-mounted antenna and a bottom-mounted antenna, the new method allows for a realistic model of the Earth-surface multipath environment. Narrow-band and wide-band airborne receivers are simulated, and their responses to Earth-surface multipath are evaluated. The two receivers are found to have different code phase error signatures in the same multipath environment. Under different conditions, both receivers can experience smoothed pseudorange bias of up to 0.3 m.

Structure Computation of Quiet Spike Flight-Test Data During Envelope Expansion

System identification or mathematical modeling is used in the aerospace community for development of simulation models for robust control law design. These models are often described as linear time-invariant processes. Nevertheless, it is well known that the underlying process is often nonlinear. The reason for using a linear approach has been due to the lack of a proper set of tools for the identification of nonlinear systems. Over the past several decades, the controls and biomedical communities have made great advances in developing tools for the identification of nonlinear systems. These approaches are robust and readily applicable to aerospace systems. In this paper, we show the application of one such nonlinear system identification technique, structure detection, for the analysis of F-15B Quiet Spike(TradeMark) aeroservoelastic flight-test data. Structure detection is concerned with the selection of a subset of candidate terms that best describe the observed output. This is a necessary procedure to compute an efficient system description that may afford greater insight into the functionality of the system or a simpler controller design. Structure computation as a tool for black-box modeling may be of critical importance for the development of robust parsimonious models for the flight-test community. Moreover, this approach may lead to efficient strategies for rapid envelope expansion, which may save significant development time and costs. The objectives of this study are to demonstrate via analysis of F-15B Quiet Spike aeroservoelastic flight-test data for several flight conditions that 1) linear models are inefficient for modeling aeroservoelastic data, 2) nonlinear identification provides a parsimonious model description while providing a high percent fit for cross-validated data, and 3) the model structure and parameters vary as the flight condition is altered.

Comparative Flight Tests With and Without Tip Tanks

crossover point of 157 kt true airspeed and 62% brake horsepower the effect of tip tanks is neutral. The crossover point closely corresponds with typical cruise operating conditions and altitudes as well as Carson cruise conditions for this aircraft. The results are expected to be typical for similar aircraft. A flight test data reduction and analysis technique based on true airspeed rather than calibrated airspeed is detailed.

Adaptive Stochastic Filtering for Online Aircraft Flight Path Reconstruction

State and parameter estimation using flight test data is highly affected by process and measurement noises, especially with noises displaying time varying statistical properties. Hence, if an estimation problem is to be solved, an adaptive filtering approach is recommended. It is also desirable to obtain the estimates online, simultaneously with flight execution, aiming at a maneuver validation before concluding the flight. Indeed, it is more expensive to put the aircraft back in the air than to extend a little the flight and repeat a test point. Flight path reconstruction is a technique which produces a consistent flight test data set from noisy measurements as a preprocessing scheme to a parameter identification routine. Air data can also be calibrated simultaneously if the problem is formulated properly. This work proposes a methodology to deal with time varying noise statistical properties using a new approach for an adaptive extended Kalman filter. Besides the main filter, two other Kalman filters are proposed to run in parallel, to estimate the process and measurement noise statistics based on the main filter residuals. The proposed adaptive method is derived from the covariance matching technique, by employing filter residuals to adjust the noise statistical properties. Because the method has a low computational cost and is recursive, it is suitable for online applications. The method is validated in a flight path reconstruction application, with simultaneous air data calibration for angle of attack, angle of sideslip, and static pressure sensors. A 100 samples Monte Carlo simulation and real flight test data analysis are used for performance evaluation. Because the proposed approach adequately estimates the statistical noise properties, improved performance is obtained.

Aircraft Characterization in Icing Using Flight Test Data

The University of Illinois, in conjunction with NASA Glenn, has conducted a flight test program to investigate aircraft icing effects and develop aircraft icing effects characterization techniques. Flights were conducted in 2001 and 2002 to collect data in clear air as well as in natural icing conditions. These data were used to identify the effects of icing on aircraft performance and control. It was also used to aid in the development of an H ∞ characterization algorithm being designed specifically for the Smart Icing System (SIS). Flight test data analysis was accomplished using a modified stepwise regression technique. Systems IDentification Programs for Aircraft (SIDPAC) was used for the linear regression analysis. The results of this analysis revealed multiple parameters that clearly indicated both the presence and severity of the ice accretion. Atmospheric turbulence was shown to significantly affect this method of parameter identification. A real-time H ∞ parameter identification (PID) algorithm has previously been developed as part of the icing characterization function of the Smart Icing System. This paper presents an initial validation of the H ∞ PID algorithm wherein the algorithm is applied to the flight test data after the fact, but in a manner that is consistent with the ultimate real-time application. This mock real-time validation demonstrates that the H ∞ PID algorithm provides pitching moment derivative estimates that are consistent with those provided by SIDPAC for both clear-air and icing conditions in the absence of turbulence. As with the stepwise regression technique, the H

Application of Parameter Estimation to Improved Autogyro Simulation Model Fidelity

Development of an airworthiness design standard for light autogyros is underway in an attempt to improve a poor safety record. Mathematical modeling is playing a vital role in the understanding the flight mechanics of these rotorcraft. Unlike helicopters, autogyros have not received the attention of the technical community until recently, and, as a consequence, there is little theoretical analysis or experimental flight testing that makes use of contemporary methods. As a result, validity of mathematical modeling has relied on analysis of flight-test data from experiments conducted with two different aircraft. Parameter estimation by the use of a simple frequency-domain, equation-error approach has proved to yield consistent and robust results from each aircraft, highlighting the same mismatches between theory and experiment in both cases