-arcseconds (mas). First results show that we are able to achieve the required centroiding precision and simulations indicate that when the final observations come in we should be able to achieve our goal of parallaxes with accuracies of 2 mas. The main problems will be focal plane astrometric distortions

mosaics in drift-scan mode in the focal plane of Fizeau interferometers. The astrometric measurement, i.e. the determination of the one-dimensional relative position of the fringe pattern, perpendicular to the fringes (i.e. in the direction of the sky scan), and the extraction of the spectro

The eciency of single dish mapping and synthesis array mosaicing can be increased by completely sampling the information in the antenna's focal plane. This requires a densely packed array of electrically small elements. Each telescope beam is formed with a weighted combination of signals from

We consider the use of spatial filtering algorithms for radio frequency interference (RFI) mitigation in conjunction with a focal plane feed array of electrically small elements. Numerical simulations are used to study the performance of 7 and 19 element hexagonal dipole arrays with a 25 meter

). These will enable a reliable geometric calibration of solid-state mosaic detectors in the focal plane of large ground-based telescopes and make a substantial contribution to our understanding of stellar populations in the Milky Way. In this paper we motivate the need for such standards and discuss the strategy

& MOM), focal plane camera electronics (ATC & FTC), camera cooling cryo-heat pipe, and the siderostat mechanism are currently under development. Main assemblies are built to meet flight requirements and have been or will be subjected to flight qualification level environmental testing (random

the internal parameters of the camera, including the effective focal length, one-pixel width on the image plane, image distortion center, and distortion coefficients. The number of parameters to be calibrated is reduced by using a calibration pattern with equally spaced ots and assuming a pin-hole model camera

In this paper, a novel focal plane calibration algorithm is presented using a multi-resolution learning algorithm, that can be implemented online. For global learning of the distortion map, the use of a radial basis function network is advocated whereas a local approximation method known as moving

-Hartmann wavefront sensor consists of a lenslet array placed in the aperture plane of the telescope which subdivides the complex field in the aperture plane. The lenslet array can also be used to achieve subdivision at the focal plane. We present a Fourier analysis of the latter approach and compare with the Shack

-constants and array geometry, telescope pointing errors, scan speeds and scanning angles, sky noise and sky rotation. GENERATING REALISTIC SYNTHETIC TIME-SERIES A mapping simulator has been developed to generate synthetic bolometer time-series data and associated astrometric information which are then run through a