系统误差

a system of along-track mode sar based on the gps is established.by seeing the gps signal as a chirp,chirp scaling algorithm of this mode with large squint angle is investigated.chirp scaling algorithm is considered more efficient and widely applicable when the bistatic sar system is in side-look or small squint angle mode,but in large squint angle case,the errors caused by taylor expansion are so large that the algorithm could lose its precision.in such a case,an equivalent mono-static sar range mode which has fewer errors than taylor expansion with large squint angle is proposed to substitute the range history of bistatic sar.then bistatic sar images with large squint angles are gotten by common nonlinear cs algorithm.the effectivity of the method is verified by matlab simulation.

摘 要：建立了基于gps的顺轨sar系统模型，通过将gps信号等效为chirp信号，研究了在该模式下的大斜视角chirp scaling算法。在正侧视或小斜视情况下，cs算法具有较好的聚焦性能和广泛的适用性，但在斜视角较大的情况下，该算法将散焦而不能成像，因而提出了用等效的单基地距离模型来代替双基地距离历史的方法，解决了大斜视角情况下距离模型二阶近似误差较大的问题，并结合单基地非线性cs算法，实现了在大斜视角情况下的基于gps反射信号的双基地sar高精度成像，最后通过matlab仿真进行了验证。

In the new models, there is no need to level and orientate theodolites for self--locating of GeoIMS. Comparing with the common model, the new models can eliminate the errors of levelling and orientating in self-locating of GeoIMS. So it is pos sible to improve greatly the precision of GeoIMS in the new models.

与传统模型相比，这几种新的自定位模型或者不要求仪器严格整平，或者不要求仪器进行相对定向，因此不再受仪器的整平、定向等误差的影响，从而使得系统的整体测量精度大幅度提高成为可能。

The optical signals were converted to electrical ones, pre-amplified, sent to data acquisition system through sample held. Then the error of the measuring screw-pitch was achieved after the data were processed with the software Matlab.

测量的信号经光路转换及前置放大后，通过采样保持送入数据采集系统，经数据处理软件Matlab进行处理得出螺距误差。

Are due to the practical limits to which correction can be made for systematic effects, such as offset of a measuring instrument, drift in its characteristics between calibrations, personal bias in reading an analogue scale or the uncertainty of the value of a reference standard.

其它非理想性因素是由于对系统效应的修正产生的实际限制，比如测量仪器的误差，两次校验之间的性质偏移，个人读取量数的偏差或者参考标准值的不确定性。

Other imperfections are due to the practical limits to which correction can be made for systematic effects, such as offset of a measuring instrument, drift in its characteristics between calibrations, personal bias in reading an analogue scale or the uncertainty of the value of a reference standard.

其它非理想性因素是由于对系统效应的修正产生的实际限制，比如测量仪器的误差，两次校验之间的性质偏移，个人读取量数的偏差或者参考标准值的不确定性。

To solve the above problems, a novel resonance injection type hybrid active power filter is presented, it allows the energy exchange between the DC-side capacitor and grid, DC-side voltage will be stabilized after the proposed control method base on the regulation of reactive current is adapted. On the other hand, a new current control method is proposed which is based on the control of error between injection current and harmonic current compensated by passive power filter using recursive PI.

在此基础上结合提出的基于基波无功电流闭环调节的直流侧电压控制方法，保证了直流侧电压的稳定；提出了采用递推积分将无源滤波器作用后电网谐波电流与注入支路补偿电流进行闭环比较控制以获得参考电流的方法，减小了误差，提高了系统的控制精度。

A new launch vehicle telemetry system scheme with an independent sub-system of environmental measurement is designed, which could analyze environmental data on rocket and then sends analysis results instead of original measurement data to the ground station during the flight tests. And a method of overlapping data segmentation is presented for solving the error-accumulation problem caused by calculating the shock response spectra during the whole flight. Besides, the rocket-borne optimal process parameters of the acoustic noise, shock and vibration are obtained by simulation combined hardware resources and system capacity.

通过设计独立的力学环境测量及数据处理子系统构建新的遥测系统体系结构，在箭上完成力学环境数据处理并将处理结果代替原始测量数据发到地面；提出了数据重叠分段处理方法，解决了飞行全程处理冲击响应谱的误差积累问题；建模仿真给出了箭上力学环境数据的优化处理参数；完成了箭上实时处理器设计。

The intelligent cablefault location instrument has many peculiarity by testing fault cable in laboratory ,for examplethe measure range is 0 ～ 60kM, the relative error is smaller than 0.5%. In-systemProgramming logic device which will be useful in debuging the circuit board is used.Measurement date can be displayed by the LDE showing, and it has the USB port supporting"Plug and Play" with electricity, the highest rate is 12Mb/s.

经过模拟电缆电路定点实验得出该测试仪具有以下特点：测量量程为 0～60km，相对误差不大于 0.5%；有利于方便调试的在系统可编程逻辑器件的应用；LED 显示器可动态显示测量结果；USB热插拔通信接口功能，传输最高速率为 12M。

On the base, the error sources of the whole accelerators system are analyzed.

在此基础上，对整个加速度计系统的误差来源进行了分析。

The positioning error of accelerometers due to a clock jitter is analyzed by Monte Carlo analysis method.

采用蒙特卡洛分析法，对由于时钟抖动造成的加速度计定位误差进行了系统的分析。

As she looked at Warrington's manly face, and dark, melancholy eyes, she had settled in her mind that he must have been the victim of an unhappy attachment.

每逢看到沃林顿那刚毅的脸，那乌黑、忧郁的眼睛，她便会相信，他一定作过不幸的爱情的受害者。

Maybe they'll disappear into a pothole.

也许他们将在壶穴里消失