外文文獻(xiàn)翻譯中英文對照測繪工程gps數(shù)據(jù)的處理方法在結(jié)構(gòu)變形監(jiān)測的應(yīng)用-資料下載頁
2024-12-06 05:20本頁面
【導(dǎo)讀】下對大型土木工程結(jié)構(gòu)進(jìn)行監(jiān)測。然而,多路徑效應(yīng)和低采樣頻率的精度影響GPS. 另一方面,加速度計靜態(tài)和低頻不能有效的措施結(jié)構(gòu)反應(yīng),但可以精確。因此,本文僅探討GPS與測量結(jié)合的可能性，信號提高對測。經(jīng)驗(yàn)?zāi)Ｊ椒纸夂妥赃m應(yīng)濾波的方法。一系列的運(yùn)動模擬臺試驗(yàn)，然后根據(jù)。型的運(yùn)動定義為輸入，在波時間歷程一個預(yù)先定義的靜態(tài)的位置。通過實(shí)測位移運(yùn)動產(chǎn)生運(yùn)動仿真的“桌子”。比較結(jié)果表明,該技術(shù)能顯著提高。測,然后采用動態(tài)位移響應(yīng)表達(dá)式，用雙重整合的測量加速度響應(yīng)。構(gòu)在全球風(fēng)力范圍和連續(xù)工作的氣象條件下的變形。然而,GPS位移測量的準(zhǔn)確性。取決于許多因素,包括衛(wèi)星覆蓋,大氣的影響,多路徑,GPS數(shù)據(jù)處理方法。這就要求采樣率大大高于感興趣的頻率成分的連續(xù)構(gòu)造變形的信號。顯然,GPS測量性能與加速度計互補(bǔ)。加速度時程來衡量一加速度計以獲得高頻動態(tài)響應(yīng)頻率成分比截止頻率。
【正文】 ns generated by the motion simulation table. 2 Empirical Mode Deposition and Adaptive Filter The EMD used in this study is to depose GPSmeasured structural displacement response time history x(t) into a number of IMF ponents and a final residual through a sifting process (Huang et al. 1998): x(t) =cj(t) + r(t)Ne whereNe is the number of IMF ponents。 and r(t)Ne is the final residual. This final residual of the structural displacement response time history, measured by GPS, is a monotonic function that can be defined as the mean displacement of the structure. As the concept of this deposition is based on the direct extraction of the energy associated with various intrinsic time scales of the time history itself, mode mixing during the sifting process would be possible. A criterion, termed the intermittency 2021 屆測繪工程專業(yè)畢業(yè)論文外文翻譯 9 check, was thus suggested by Huang et al. (1999) to separate the waves of different periods into different modes based on the period length. In this study, the EMD with an intermittency check and a cutoff frequency _c are used to process acceleration time history measured by an accelerometer so as to obtain a highfrequency dynamic response of frequency ponents greater than the cutoff frequency. An adaptive filter, used as a signal deposer, operates on the information from two measurement inputs with the same length: (1) a primary measurement p(k) that contains the desired signal of interest s(k) contaminated by noise n(k), and (2) the reference measurement r(k) of noise signal n_(k). In order to extract the desired signal s(k) from the polluted primary measurement p(k) by using the adaptive filter, two conditions have to be satisfied: (1) the desired signal s(k) and noise n(k) in the primarymeasurement are uncorrelated with each other。 (2) the noise n_(k) in the reference measurement is uncorrelated with the desired signal s(k) but correlated in some way with the noise ponent n(k) of the primary signal. As the multipath measured by the moving receiver is similar to that measured by the stationary receiver between sidereal days at our test site (Chan et al. 2021), the adaptive filter can actually be applied tomitigate the multipath. The displacement measured by the GPS with a moving antenna is taken as the primary measurement p(k), which includes the desired structural displacement s(k) and the multipath effect n(k). The signal measured by GPS with a stationary antenna during the same time period as the dynamic measurement, but on the next or previous sidereal day, is taken as the reference measurement r(k) = n_(k). By assuming that the desired structural displacement is uncorrelated with the multipath while the reference measurement is uncorrelated with the structural displacement, but correlated in some way with the multipath effect, the adaptive filter can thus be applied in this study. Apart from the multipath mitigation, this study also uses the adaptive filter to extract lowfrequency dynamic displacement response from the GPSmeasured data by using highfrequency dynamic displacement response from the accelerometer as a reference measurement.
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