Accurate spacecraft attitude estimation with the ESA starmapper

The ESA starmapper is an optical-electronic instrument with an array of photo-sensitive slits, to "be strapped down to spinning spacecraft. Recorded times of passage of known stars over these slits, together with mathematical models for spacecraft dynamics and starmapper instrument, provide the basis for recursive estimation of the spacecraft...

Aircraft design loads due to non-stationary atmospheric turbulence patches

In this report it is assumed that atmospheric turbulence appears in patches and that within the patches the turbulence can be described.as a modulated Gaussian process. The patch lengths have a certain probability density function. Load exceedance curves and design loads for various aircraft models for this turbulence model are compared with...

Het meten van lichtreflecties van gewassen

Measurement of an object's reflectance spectrum can provide information on its nature and qualities. However, one should thoroughly take into account the fact that in general the reflectance spectrum does not only depend on the object itself, but also on the parameters defining the measurement conditions, like the spectral and spatial...

A non-stationary model for atmospheric turbulence patches, for the prediction of aircraft design loads

In this report a model for atmospheric turbulence is proposed. It is assumed that atmospheric turbulence appears in patches and that within the patches the turbulence can be described as a modulated Gaussian process. Statistical properties of this model and of atmospheric turbulence are compared. Using data from various sources a probability...

Digital filtering methods, with applications to satellite attitude determination in the presence of modelling errors. Part I: theory

The report reviews a number of digital filtering methods and gives examples of their application. The methods include batch processing methods and rec\irsive methods, not only in the classical formulations but also in square-root formulations. The latter formulations have the purpose to prevent certain numerical inconveniences. Much attention is...

Equations for the response of an airplane to non-stationary atmospheric turbulence patches

In this report a method is described to calculate the load exceedance curve for a linear system having a finite, modulated Gaussian process as input. The derivation is based on the use of ensemble averages, defined as the expected values at a certain point of time. The equations can be used for any airplane-transfer function for which the Power...

Comparison between the statistical discrete gust method and the power spectral density method

The Power Spectral Density method and the Statistical Discrete Gust Method to calculate aircraft design loads due to atmospheric turbulence are compared qualitatively and quantitatively on the basis of the load exceedance curves for certain aircraft models. It is shown that both methods are related to each other, giving the same results for...

Reproductie zouttoestand getijrivieren (IV): Voorbereidend onderzoek tweelingproeven

An analytical model of the write and read process in digital magnetic recording with a linear recording medium

A study of surface treatment of aluminium alloy samples by measuring light stimulated electron emission and contact potential

Tests on samples anodized in a tartrate solution indicated that porefree thin oxide films prevent almost all light stimulated electron emission. Probably "pores" are requisite for emission. The c.p. and emission as function of the pickling time in chromic-sulfuric acid solution could be explained qualitatively. The micro etch pit structure with...

Reproductie zouttoestand getijrivieren (V): Numerieke aspecten gegevensverwerking getijgootonderzoek

Refurbishment of Residential Buildings: A Design Approach to Energy-Efficiency Upgrades

Refurbishing the existing building stock is an acknowledged issue in the building industry. Even though awareness has been raised, the design phase of refurbishment projects is often problematic. The decisions taken in the early stages of the design determine the final result; however, the assessment of the environmental performance only happens...

Stochastic parameterization of convective area fractions with a multicloud model inferred from observational data

Observational data of rainfall from a rain radar in Darwin, Australia, are combined with data defining the large-scale dynamic and thermodynamic state of the atmosphere around Darwin to develop a multicloud model based on a stochastic method using conditional Markov chains. The authors assign the radar data to clear sky, moderate congestus,...

Lecture notes on "The Role of Rivers to Mankind"

It is the task and target of River Engineering as a profession to provide all the tools for arriving at an optimum utilization of the potential resources, optimum in the sense of promoting the beneficial characteristics of the river and eliminating or at least checking the adverse qualities. To strive for this aim, there must be a scientific...