方位

A new cotangent theorem is deduced to solve the nonlinearity for bearing-only measurement.

通过新提出的余切关系定理，解决了单站纯方位观测的非线性问题。

Also choose elevation angles as positive above the boresight axis and negative below, and choose azimuth angles as positive in a clockwise direction and negative in a counterclockwise direction.

同时规定波束仰角在视轴线以上为正，以下为负，方位角以顺时针方向为正，逆时针方向为负。

The main job and contribution of this paper are as follows:Based on narrowband signal processing, we propose a new method for FH signal blind detection and blind parameter estimation. Firstly, compute the cross-correlation function of FH signals from multichannels, then we get the cross power spectral density matrixCSDM Secondly, select the hops of FH signals from the CSDM via processing and analyzing the CSDM, meanwhile reduce the influence coming from noise, fixed frequency signal and other interferences; Lastly, estimating the DOA of every hop and according to the DOA, we can separate the hops, get the number of FH signals and their parameters. Propose a new method for designing the threshold in FH signal detection. This method makes it easy to get the threshold by theoretic computing and it can extremely reduce the interference of non-FH signals.Based on broadband signal processing, we propose a new method for FH signal blind detection and blind parameter estimation. Firstly, get the DOA of the signals by wideband spatial spectrum estimation; secondly, separate the signals by spatial filtering using wideband beamformer; Lastly, we propose two methods for FH signal blind detection and blind parameter estimation, one is for several constant hop-rate FH signals whose dwell-time are different and another is for a single FH signal whose hop-rate is alterable.By employing spatial interpolation in broadband signal beamforming, it can reduce the number of antenna elements and corresponding RF modules, A/D converters, etc. It can also eliminate the mutual coupling between antenna elements while getting the narrower main beamwidth and lower sidelobe level.

本文的主要研究工作和贡献如下：●提出了一种基于窄带处理的FH信号盲检测和参数盲估计的实现方法，即首先求出多路信号之间的互相关，进而得到互功率谱密度矩阵，然后通过对CSDM进行对折处理来抑制噪声、定频信号及其他干扰的影响，并将所有属于FH信号的hop(每一跳的驻留时间在时频图上持续的线段)从CSDM中筛选出来，最后用阵列信号处理中的到达方向估计理论在频域中估计出各个hop的方向参数，利用方位信息完成FH信号分离并得到FH信号的数目及其各自的参数集；●提出了一种确定FH信号检测门限的策略，该策略不仅使得检测门限能够通过理论计算得到，而且还显著地抑制了非跳频信号的干扰，从而能有效地检测出FH信号；●提出了一种基于宽带处理的短波FH信号盲检测和参数盲估计的实现方法，即首先利用宽带空间谱测向技术得到接收信号的DOA，然后采用宽带波束形成技术对特定方向进行空间滤波，实现多个信号的分离，最后分别提出了两种FH信号的盲检测和参数盲估计方法，第一种方法适用于空间某个特定方向上存在着几个驻留时间不同的恒跳速FH信号和其他干扰信号的混合信号，第二种方法适用于空间某个特定方向上仅含一个可变跳速的FH信号和噪声的混合信号；●将空间插值的概念和宽带波束形成技术结合起来，提出了一种基于频域处理的宽带恒定束宽的波束形成方法。

Through contrast and analysis of two sets of designed parameters, the result shows that optimizing method can obtain more satisfying effect in the hand of narrow azimuth seismic survey and equilibrium distribution of inline and crossline coverage.

应用该设计方法对胜利探区4个实际区块的观测系统参数进行了优化设计和对比分析，结果表明，在窄方位角采集，纵横向覆盖次数均匀分布等方面该方法的效果较好。

To address the problems that full volume 3_D DSR equation migration could meet with in production application, we present a feasible common_azimuth prestack τ migration approach based on the theory of crossline common_offset migration.

为了克服其全三维偏移算法在实际应用中可能面临的困难，本文采用稳相近似，在crossline常炮检距偏移理论基础上推导了实用的共方位角叠前τ偏移方法。

Finally by analyzing the measured data, it is shown that this method can detect the currents efficiently and effectively.

最后通过对实测数据的分析表明文中的方法可以快速有效地进行洋流方位探测。

Assuming that both parties have rejected your attempts to de-escalate and have taken up positions facing each other , you should orient yourself so you can intercept an assault directed at your friend .

假设双方都拒绝了您的企图德-升级，并已采取了立场，面对对方，你应该确定自己的方位，让您可以拦截殴打针对您的朋友。

I could not take the declension of the sun at noon today, again due to overcast. But I

由于多云天气再次出现，今天我没法儿从观测中午太阳倾角来判定方位。

Second,it introduces an additive phase component which induces defocus in cross-range.

二是引入了附加的相位分量，在方位向造成散焦。

To get it treated,they can devolve into full-on heart attacks.

失去你的工作他们就会转变成全方位的心脏病发作

It has been put forward that there exists single Ball point and double Ball points on the symmetrical connecting-rod curves of equilateral mechanisms.

从鲍尔点的形成原理出发，分析对称连杆曲线上鲍尔点的产生条件，提出等边机构的对称连杆曲线上有单鲍尔点和双鲍尔点。

The factory affiliated to the Group primarily manufactures multiple-purpose pincers, baking kits, knives, scissors, kitchenware, gardening tools and beauty care kits as well as other hardware tools, the annual production value of which reaches US$ 30 million dollars.

集团所属工厂主要生产多用钳、烤具、刀具、剪刀、厨具、花园工具、美容套等五金产品，年生产总值3000万美元，产品价廉物美、选料上乘、质量保证，深受国内外客户的青睐