衛星監測及干擾源定位技術可行性之研究

Abstract

在此計畫中，吾人將利用數值方法評估現有的衛星干擾源定位技術，包含到達時間差/到達頻率差、單一到達時間差、單一到達頻率差與多波束天線等方法之定位精準度並視其應用於我國之可行性，上述前三項技術經多次定位，最後可計算出一定位誤差橢圓。其中需考慮一些會影響定位精準度的項目，如衛星星曆表與信號傳輸路徑特性等，再依據模擬評估後所得到的結果，給予衛星干擾源定位技術之可行性建議。 另外，為了改善雙星定位動輒數十公里，甚至數百公里的定位誤差，吾人規劃混合式定位法，該方法結合到達時間差/到達頻率差與多波束天線的定位技術，期望有效的降低定位誤差，進而提高定位精準度，而此處的多波束天線是利用一滯留於空中的直昇機來達成。此外，我們利用地面監測站可能收到干擾源旁波瓣電波的機制，規劃及評估利用地面監測站定位干擾源之可行性及準確度，初步規劃將使用雙抵達角度定位。

In this proposal, we plan to evaluate the accuracy of the satellite interference positioning techniques, including Time Differential of Arrival (TDOA)/Frequency Differential of Arrival (FDOA), TDOA-Only, FDOA-Only and Multi-beam Antenna (MBA) through numerical. The calculation simulator results in error ellipses using these three techniques. Other causes of location error include the satellite ephemeris accuracy and propagation effects. Our simulation results can be used to evaluate the feasibility of these techniques when applied to the cases in Taiwan. In order to reduce the positioning error of the TDOA/FDOA techniques, we propose a hybrid method that combines TDOA/FDOA and MBA potioning techniques to reduce the positioning error. The proposed MBA technique makes use of a helicopter to achieve the geolocation in this hybrid method. We will evaluate the positioning accuracy of this method. This represents one more option for the DGT？HHH？HHHs consideration in the future. We also propose another method using arrayed ground stations, which not only monitor regular satellite uplink signals but also pin-point un-expected interference sources. These monitoring stations may receive the electromagnetic wave from the side lobes of the interference sources, which may be located by using the AOA (Angle-of-Arrival) method. Feasibility study of this method will be carried out through numerical simulation method.