## 1 Introduction
The spectral characteristics of each filter are determined by the resonant behaviour of filter line section and by the strength of coupling to the feed and detector. The superconducting filterbank approach delivers a large number of narrow and very low noise spectral channels in a small and rugged package. The design of the filters gives great control over channel placement and shape, and these need not be regular. This combination is near ideal for a hyperspectral sounding instrument: close-packed arrays of narrow channels can be provided to cover key lines in a wide bandwidth, along with broad channels for background subtraction. Technology advancements naturally lead to promising new instrument concepts for applications in different types of atmospheric monitoring areas, above and beyond temperature and humidity sounding and cloud sensing, etc. The development and definition of instrument concepts requires consideration of many interlinked design factors, such as observational requirements (geophysical variables to be measured), technology requirements and limitations, mission requirements etc. Trade-off analysis between these parameters is necessary to identify the instrument design that provides the optimum performance [17]. To quantitatively analyse the performance of an instrument and to optimise its concept design via trade-off analysis, the implementation of an end-to-end simulation process is required. An end-to-end simulation is an important part of the atmospheric observing system design process [18]. To support studies related to new instrument concepts and their evaluation for atmospheric remote sensing and NWP applications, we have developed a generic end-to-end instrument performance simulation system (EIPS) framework for satellite atmospheric sounding instruments. The radiative transfer forward model which is incorporated as one of the component of EIPS framework is the Havemann-Taylor Fast Radiative Transfer Code (HT-FRTC) [19]. The HT-FRTC has been applied across the EM spectrum in a number of previous studies, both in the infrared [20; 21; 22; 23] and in the short-wave and part of the ultraviolet [24; 25]. The HT-FRTC has been used to evaluate different configurations of an infrared satellite radiometer concept based on laser heterodyne technology [26]. Using the HT-FRTC, the EIPS framework becomes applicable to any passive spectral sensor from the ultraviolet (UV) to the microwave (MW). This paper is focused on the application of EIPS framework to satellite sensors in the MW spectral range. The purpose of this paper is to give an overview of the EIPS framework and to describe the framework design, the component models and their organisation. To demonstrate the framework's flexibility in relation to advanced sensor technologies in the MW, a novel superconducting transition edge sensor (TES) based multi-spectral MW instrument has been presented as an example. Furthermore, as an example of the framework's application, we have applied it by conducting a case study, in which we analysed and compared the relative performance of existing multi-spectral type MW instruments with a TES technology based multi-spectral MW instrument. In Section 2 of this paper, we present a useful overview and a visualisation of a general atmospheric observing system design process using which the EIPS framework has been derived. The description of the EIPS framework, its building blocks, and their organisation are presented in Section 3. And in Section 4 we present the application of EIPS framework through a case study of comparative performance analysis between existing and emerging technology-based satellite MW remote sensing instruments (as described in above paragraph).