基于短基线差分干涉法的上海地面沉降分析

利用短基线差分干涉时序分析方法获取上海城区的地面形变信息.短基线时序分析方法选择较短的干涉对组合,利用干涉对中的高相干目标的相位和幅度信息在长时间序列中保持稳定的特性,获得高精度的地表形变信息.实验选择上海外环以内的区域,利用2007—2010年间的17景日本ALOS卫星的PALSAR数据,采用短基线时序分析方法提取了相干目标视线向的平均沉降速率.在沉降速率图中,杨浦区与虹口区交界处存在一个明显的漏斗状沉降;闵行区和浦东新区出现了一个较大范围的不规则的沉降条带.

复合成孔灌注桩技术工程应用研究

湿陷性黄土地基处理时,受到扬尘、噪音等环境治理的影响,挤密(灰)土桩、夯实水泥土桩等常规处理方法的应用逐渐受到限制。针对基底下分布有限厚度湿陷性黄土的工况,提出一种上部静压挤土、下部长螺旋取土复合成孔的灌注桩技术,将挤土密实效应和竖向增强作用有效结合,应用于湿陷性黄土地基的复合地基加固或桩基础。较常规湿陷性地基处理方法相比,该技术有较好的质量保证,施工中不易发生缩孔、断桩等问题。工程实践与现场试验分析表明,该技术适用于处理基底以下一定厚度的湿陷性黄土地基,亦适用于受扬尘、噪音等环境治理限制条件下的湿陷性地基处理工程,可为类似场地地基处理方案提供参考。同时对挤密桩间距的设计方法进行了分析,提出目标干密度的概念并应用于挤密桩间距的确定。

CDMA系统中的一种分布式功率控制算法

通过仿真、对比分析了一种基于效益函数的博弈功率控制(UBPC)算法与DPC功率控制算法用于CDMA系统的性能。结果表明恰当选择效益函数和代价函数后,博弈功率控制算法可解决DPC算法因用户数的增加而发散的问题,并且可以保证用户的QoS要求及用户间的公平性,同时算法的收敛速度对用户数不敏感。

非理想功率控制下WCDMA系统中的业务速率与系统容量

根据 WCDMA系统单小区功率分配算法有解的充要条件,通过将目标信干比抽象为对数正态随机变量的方法,该文得出了非理想功率控制条件下系统容量的定量关系式,为研究非理想功率控制下,VBR(Variable Bit Rate)业务的速率与 CBR(Constant Bit Rate)和 VBR业务的用户容量间的关系提供了一条有效的途径。分析和数值计算结果表明,非理想功率控制对系统性能有着显著的影响,业务速率和系统容量之间存在的互换关系。可以根据不同业务的性能要求,通过改变业务参数来提高系统的适应性,从而提高系统的资源利用率和服务质量。

A novel SINR and mutual information based radar jamming technique

The improvements of anti-jamming performance of modem radar seeker are great threats to military targets. To protect the target from detection and estimation, the novel signal-to-interference-plus-noise ratio （SINR）-based and mutual information （Ml）-based jamming design techniques were proposed. To interfere with the target detection, the jamming was designed to minimize the S1NR of the radar seeker. To impair the estimation performance, the mutual information between the radar echo and the random target impulse response was used as the criterion. The spectral of optimal jamming under the two criteria were achieved with the power constraints. Simulation results show the effectiveness of the jamming techniques. SINR and MI of the SINR-based jamming, the MI-based jamming as well as the predefined jamming under the same power constraints were compared. Furthermore, the probability of detection and minimum mean-square error （MMSE） were also utilized to validate the jamming performance. Under the jamming power constraint of I W, the relative decrease of the probability of detection using S1NR-based optimal jamming is about 47%, and the relative increase of MMSE using Ml-based optimal jamming is about 8%. Besides, two useful jamming design principles are concluded which can be used in limited jamming power situations.

SIGNATURE DRIVEN MULTIPLE TARGET TRACKING

Tracking multiple maneuvering targets remains a challenge due to the existence of clutter and the disturbance of spurious targets. Traditional tracking algorithms treat target measurements as points which results in the loss of information. We have propose a Signature Driven multiple-target Tracking (SDT) method which uses target signature in spectral,spatial and temporary spaces as well as the Markov property of target motion,and the data association process in SDT is very effective. The experimental results have shown its outstanding performance.

Dual-Tone Radio Interferometric Positioning Systems for Multi-Target Localization Using a Single Mobile Anchor

In this paper, a low-cost dualtone radio interferometric positioning system using a single mobile anchor is proposed to locate multiple targets at the same time. We name it mDRIPS. In mDRIPS, each target continuously transmits a dual-tone signal with its dedicated frequencies, and the mobile anchor receives the signals at different positions along its trajectory, Neither time synchronization between the mobile anchor and the targets nor time synchronization among the targets is required. We take the instability of targets clocks into consideration and develop an ESPRIT-type algorithm to estimate frequencies of each dual-tone signal. Furthermore, the time of arrival （TOA） of each target signal is extracted from the phase estimates of the received dual-tone signals. After measuring several TOAs at different locations along the anchor＇s trajectory, each target can be located. Since the frequency difference of the two tones of each dualtone signal is designed to be smaller than the channel coherence bandwidth, the same fading effect on these two tones can be eliminated. Moreover, the integer ambiguity problem due to phase wrapping is investigated, and a localization algorithm to deal with a simplified ambiguity problem is proposed. Numerical results demonstrate the efficiency of the proposed mDRIPS.

Space luminous environment adaptability of missile-borne star sensor

To solve the problem of stray interference to star point target identification while a star sensor imaging to the sky, a study on space luminous environment adaptability of missile-borne star sensor was carried out. By Plank blackbody radiation law and some astronomic knowledge, irradiancies of the stray at the star sensor working height were estimated. By relative astrophysical and mathematics knowledge, included angles between the star sensor optical axis point and the stray at any moment were calculated. The calculation correctness was verified with the star map software of Stellarium. By combining the upper analysis with the baffle suppression effect, a real-time model for space luminous environment of missile-borne star sensor was proposed. By signal-noise rate （SNR） criterion, the adaptability of missile-borne star sensor to space luminous environment was studied. As an example, a certain type of star sensor was considered when imaging to the starry sky on June 22, 2011 （the Summer Solstice） and September 20, 2011 （August 23 of the lunar year, last quarter moon） in Beijing. The space luminous environment and the adaptability to it were simulated and analyzed at the star sensor working height. In each period of time, the stray suppression of the baffle is analyzed by comparing the calculated included angle between the star sensor optical axis point and the stray with the shielded provided by system index. When the included angle is larger than the shielded angle and less than 90~, the stray is restrained by the baffle. The stray effect on star point target identification is analyzed by comparing the irradiancy of 6 magnitude star with that of the stray on star sensor sensitization surface. When the irradiancy of 6 magnitude star is 5 times more than that of the stray, there is no effect on the star point target identification. The simulation results are identicat with the actual situation. The space luminous environment of the missile-borne star sensor can be estimated real-timely by this model. The adaptability of the star sensor to space luminous environment can be analyzed conveniently. A basis for determining the relative star sensor indexes, the navigation star chosen strategy and the missile launch window can be provided.

一种基于用户划分的LTE上行闭环功率控制算法

长期演进(long term evolution,LTE)上行经典信干噪比(signal to interference plus noise ratio,SINR)闭环功率控制算法未考虑用户对相邻小区的干扰,导致小区总吞吐量较低。针对该问题,提出一种基于用户划分的闭环功率控制算法。根据每个用户到服务小区的路径损耗将其划分为小区中心用户或小区边缘用户,为小区中心用户设置目标SINR值时仍使用经典SINR闭环功率控制算法,为小区边缘用户设置目标SINR值时考虑其对相邻小区的干扰使用新的方法。理论分析以及MATLAB系统级仿真结果表明,与传统闭环功率控制算法和经典SINR闭环功率控制算法相比,该算法能够更加有效地降低小区间干扰,提高小区总吞吐量。