Some aerospace applications of estimation theory

In this report, the application of estimation theory to three problems from aerospace research is described. The applications considered deal with spacecraft attitude estimation, software reliability modelling and estimation, and with a satellite-based navigation algorithm. Maximum likelihood estimation is used in the software reliability case...

Estimating the probability of vertical overlap from the paired aircraft data obtained in the european vertical data collection using the program DGLDiF

The problem of estimating the probability of vertical overlap in possible future airway systems with a vertical separation standard of 1000 ft above Flight Level 290 is addressed. It forms part of an overall safety assessment of such potential systems. The problem is solved by developing a mathematical probability model of the vertical distance...

Approximate confidence regions for the parameters of three software reliability models

Expressions are derived from which confidence regions for the parameters of three specific software reliability models can be computed. These expressions are based on the asymptotic probability distribution of the maximum likelihood estimator. Some numerical results of point estimates as well as confidence regions are given, based on simulated...

Study on NAVSAT system evaluation, final report on phase 2. Part 1. Study results

Under contract to ESA, NLR has developed a flexible simulation package, named PROMISE, and a set of simulation models of the ESA proposed NAVSAT satellite-based navigation system. These were completed in 1984. In a continuation contract, described in this report, a number of extensions have been developed and implemented, and a number of...

Study on NAVSAT system evaluation, final report on phase 2. Part 2. Detailed simulation results

A positioning system based on NAVSAT

A worldwide navigation system called NAVSAT is discussed. This positioning system is based on satellites which broadcast information which can be used by receivers of this Information to estimate their position. The motion of the users is modelled by splines. The estimation procedure is based on the extended Kalman filter approach.

Verification of obstacle accountability areas using a simple mathematical model: part I: description of general model and application for a specific case

A probabilistic model is described for the lateral displacement of an aircraft after the occurrence of an engine failure during take-off. With the model, a lateral boundary is calculated, for any point of time after the engine failure, such that the probability of being within the (two sided) lateral boundary meets a specified value. Various...

Pares-preprocessing of sidelooking airborne radar data

The Netherlands remote sensing community has expressed a need for systemcorrected SLAR imagery. This means that corrections for aircraft position and attitude as well as sensor characteristics need to be applied to raw data acquired with the Netherlands digital SLAR. The PARES system was designed to fulfil this requirement. The distortions...

Estimates of spacecraft attitude and sensor parameters using adaptive filtering: Meteosat-1 transfer orbit application

In practical applications of Kalman filtering theory often inconsistencies between real estimation errors and computed error variances occur due to modelling errors. An adaptive filtering technique has been developed at NLR to deal with this filter divergence problem. Special attention is paid to divergence detection. When divergence is detected...

The use of ESA starmapper measurements for spacecraft attitude estimation: estimator design rationale and results

In order to obtain highly accurate estimates of the attitude motion of spin-stabilized spacecraft one may decide to use a starmapper as basic attitude sensor. This reliable and versatile sensor detects the times of crossing of stars over photosensitive slits. Suitable data processing techniques are needed to transform the highly accurate...

On martingales and recursive optimal state estimation

This report constitutes the deposit of a study of literature on martingales and estimation theory. Some experimental work concerning the efficiency of an estimation algorithm based on martingales is also described. The investigation has been guided by the intent to investigate martingales in relation to the Kalman and Kalman-Bucy filters and to...

A method for the calculation of 3D boundary layers on practical wing configurations

This paper gives a description of a calculation method for 3D turbulent and laminar boundary layers on non-developable surfaces. A simple eddy viscosity model is incorporated in the method. Special attention is given to the organization of the computations to circumvent as much as possible stepsize limitations. The method is also able to proceed...

Processing of Meteosat attitude measurement flight data and evaluation of the performance of an adaptive filtering technique

The attitude measurement data of the ESA geosynchronous spacecraft METEOSAT have been analyzed using an adaptive recursive filtering technique developed at NLR. The mathematical models of spacecraft dynamics and sensors have been kept very simple. Modelling errors are such that, without adaptive feed-back, strong divergence of the filtering...