高精確度IPEI太空儀器之設計與分析

Abstract

本論文主要在針對測量電離層離子特性的IPEI(Ionospheric Plasma] and Electrodynamics Instrument)太空儀器作設計與分析。首先，根據 IPEI提議書的資料，我們知道對數放大器(Log-amplifier)被使用在離子 吸收器(Ion Trap, IT)和離子漂移計(Ion Drift Meter, IDM)中。經由對 單一的對數放大器所可能造成的誤差之分析結果，我們提出一電路較簡單 並能符合需求的對數放大器；之後並分析將其應用在IT和IDM所造成的整 體誤差，而得一滿意之結果。除此之外，另一種應用於延遲電位分析器( Retard ing Potential Analyzer, RPA)的線性電流計(Linear Electrometer)，由於其輸入信號處理器(Range Control Circuit)說明不 夠明確，我們也提出一種自動交換增益控制(Automatic-Switch-Gain- Control, ASGC)方法。分析結果顯示在某些狀況下，除能滿足系統規格， 還能更進一步提高測量的精確度。綜合以上的結果，我們提出了分析設計 高精確度IPEI儀器的可行方法，做為未來實際電路設計的參考規範。 The Ionospheric Plasma and Electronics Instrument (IPEI) referred in this thesis is an instrument used for measuring the science data in the ionosphere. In this thesis, we have functionally designed the electronic circuits of the IPEI, especially we emphasize on the error analysis of the circuit. Since log-amplifiers are employed in two parts of IPEI measurement channels, Ion Trap (IT) and Ion Drift Meter (IDM), we analyze a variety of errors for an individual log-amplifier, and propose a preferred design of log-amplifier. Furthermore, by using this preferred log-amplifier, we also evaluate the overall measurement performance of IT and IDM. In addition, the linear electrometer used in Retarding Potential Analyzer (RPA) of IPEI is required to have the high measurement accuracy. To meet the operation specifications of RPA, we design an automatic-switch-gain-control (ASGC) system and analyze its functions. From the analysis results of IPEI, we have provided the design guidelines for the implementation of the high- accuracy IPEI instrument.