航天返回与遥感
航天返迴與遙感
항천반회여요감
SPACECRAFT RECOVERY & REMOTE SENSING
2014年
5期
31-37
,共7页
动量轮%扰振频谱%光轴晃动%光轴不一致%航天遥感
動量輪%擾振頻譜%光軸晃動%光軸不一緻%航天遙感
동량륜%우진빈보%광축황동%광축불일치%항천요감
momentum wheels%vibration spectrum%optical axis jitter%deviation of optical alignment%space remote sensing
随着遥感卫星分辨率的不断提高，动量轮扰振对遥感成像的影响逐渐成为卫星总体设计时需要关注的问题。目前对动量轮微振动的研究多侧重于时域分析，经常把卫星平台和载荷分立开来单独研究。鉴于平台和相机之间具有耦合作用，分立研究会带来较大误差。动量轮的输出响应并不是一个单一频率的时域信号，不同频谱对相机的影响不同，频谱分析往往更能反映问题。文章联合卫星平台和相机进行整星建模，分析了微振动扰振从动量轮处传递到相机光学元件的频谱特征，得到动量轮扰振不同频谱对相机造成的具体影响。分析结果显示，低于相机基频的动量轮扰振频谱造成相机光轴晃动，相机特征频率区间的扰振频谱不仅会放大光轴晃动，还会造成相机内部的光学元件光轴不一致。最后文章定量计算比较了这两种影响带来的MTF下降。
隨著遙感衛星分辨率的不斷提高，動量輪擾振對遙感成像的影響逐漸成為衛星總體設計時需要關註的問題。目前對動量輪微振動的研究多側重于時域分析，經常把衛星平檯和載荷分立開來單獨研究。鑒于平檯和相機之間具有耦閤作用，分立研究會帶來較大誤差。動量輪的輸齣響應併不是一箇單一頻率的時域信號，不同頻譜對相機的影響不同，頻譜分析往往更能反映問題。文章聯閤衛星平檯和相機進行整星建模，分析瞭微振動擾振從動量輪處傳遞到相機光學元件的頻譜特徵，得到動量輪擾振不同頻譜對相機造成的具體影響。分析結果顯示，低于相機基頻的動量輪擾振頻譜造成相機光軸晃動，相機特徵頻率區間的擾振頻譜不僅會放大光軸晃動，還會造成相機內部的光學元件光軸不一緻。最後文章定量計算比較瞭這兩種影響帶來的MTF下降。
수착요감위성분변솔적불단제고，동량륜우진대요감성상적영향축점성위위성총체설계시수요관주적문제。목전대동량륜미진동적연구다측중우시역분석，경상파위성평태화재하분립개래단독연구。감우평태화상궤지간구유우합작용，분립연구회대래교대오차。동량륜적수출향응병불시일개단일빈솔적시역신호，불동빈보대상궤적영향불동，빈보분석왕왕경능반영문제。문장연합위성평태화상궤진행정성건모，분석료미진동우진종동량륜처전체도상궤광학원건적빈보특정，득도동량륜우진불동빈보대상궤조성적구체영향。분석결과현시，저우상궤기빈적동량륜우진빈보조성상궤광축황동，상궤특정빈솔구간적우진빈보불부회방대광축황동，환회조성상궤내부적광학원건광축불일치。최후문장정량계산비교료저량충영향대래적MTF하강。
With the development of remote sensing satellite, the jitter of momentum wheels has more and more influence on the imaging quality. Current research of the momentum wheel vibration usually focuses on time domain, and it is usual to separate satellite platform from payload. As the platform and the payload have coupling relationship, the separate research will bring bigger deviation. On the other hand, the output of momentum wheel is not a single frequency signal, different spectrum has different effect on the camera, spectrum analysis tends to reflect more this problems like this. This paper combines the satellite platform and the camera in the same model, then analyses the frequency spectrum characteristic of the micro-vibration transmission from the momentum wheel to the optical mirrors. The result shows that the frequency spectrum below camera’s characteristic frequency mainly causes the optical axis jitter, while the frequency spectrum which fits the camera frequency causes the deviation of optical alignment as well as the optical axis jitter. Finally this paper analyses the optical axis jitter and the deviation of the optical alignment caused by momentum wheel jitter in the time domain, then calculates the decline of MTF caused by the two factors.
