伪码调相雷达高度表中多径信号抑制算法研究

多径误差是伪码调相雷达高度表中重要的误差源之一,为了提高系统的测距精度,建立了采用strobe相关器的伪码跟踪环数学模型,给出了其实现的结构框图;在考虑单路多径信号的基础上分析了多径信号的参数对伪码跟踪环的跟踪误差的影响,并在Matlab环境下对伪码跟踪环的跟踪性能进行了仿真;仿真结果表明在相同的多径参数条件下,strobe相关器可以有效地减小多径引起的跟踪误差,性能优于窄相关器,运算量较多径估计延迟锁定环要小,易于在硬件上实时实现,具有实际应用价值。     

雷达抗干扰性能评估指标分析与测试平台设计

复杂电磁环境下雷达抗干扰性能外场实验通常具有复杂度高、设备代价高昂的问题。通过分析雷达电磁环境组成和相关评估指标,在综合一系列雷达对抗想定的基础上,提出了雷达对抗性能测试系统设计方案。该系统利用高速DSP和ARM终端显示控制灵活实现雷达干扰样式选择和参数设置。有效地解决了雷达状态信息采集、回波信号实时模拟以及战场环境想定的显控终端控制。研究了多种性能评估指标的具体测试方法,分析了影响干扰效果的关键性因素。结合具体雷达设备进行了雷达抗干扰半实物仿真实验,实验和数据处理结果证明了测试方法的有效性和可行性。该方法为解决有限设备条件下雷达抗干扰性能评估、雷达系统改进提供了参考依据。     

Soil moisture estimation over vegetated terrains using multitemporal remote sensing data

A new method for retrieving soil moisture content over vegetated fields, employing multitemporal radar and optical images, is presented. It is based on the integration of the temporal series of radar data within an inversion scheme and on the correction of the vegetation effects. The retrieval algorithm uses the Bayesian maximum posterior probability and assumes the existence of a relation among the soil conditions at the different times of the series. The correction of the vegetation effects models the variation, with respect to the initial time of the series, of the component of the backscattering coefficient due to the soil characteristics as function of the variations of the measured backscattering coefficient and of the biomass. The method is tested on the data acquired throughout the SMEX02 experiment. The results show that measured and estimated soil moistures are fairly well correlated and that the performances of multitemporal retrieval algorithm are better than those obtained by employing one radar acquisition, especially in terms of capability to detect soil moisture changes. Although the approach to correct the vegetation effects on radar observations needs to be further assessed on different sets of data, this finding demonstrates that the proposed method has a potential to improve the quality of the soil moisture retrievals.     

Apriori算法在雷达故障诊断系统中的应用研究

针对某型雷达设备复杂、检修困难的问题,利用Apriori算法从该型雷达历史维修记录中提取故障征兆和故障间的关联关系,设计建立故障诊断系统。重点介绍了规则挖掘机和系统逻辑结构。使用表明该系统较好的提高了雷达故障诊断的效率,节约了诊断成本。     

A dual‐polarized cylindrical conformal array antenna suitable for unmanned aerial vehicles

A dual‐polarized X‐band conformal array antenna is presented for unmanned aerial vehicles with polarimetric radars/sensors. Starting from the planar structure, the array antenna consisted of sixteen 2 × 2 subarrays is conformal to the cylinders with various curvature radii to fit the payload box of the airborne vehicle. The return losses are almost constant even if the curvature radius changes. Measured radiation patterns are compared with various curvatures at the same frequencies. The array can be easily placed on the aircraft payload or fuselage due to its ultra thin thickness, ultra lightweight, and conformal structure, which has potential airborne applications in polarimetric radar surveillance, remote sensing, and wireless communications. © 2010 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2011.     

Optimized element positions for prescribed radar cross section pattern of linear dipole arrays

Approximate closed‐form expression is derived for the scattering from dipole arrays based on the equivalent circuit theory. Then, a method is proposed for synthesis of dipole arrays to produce desired scattering pattern using genetic algorithm (GA). In the synthesis method, the element positions in an array are considered as the optimization parameter and the derived expression is used to evaluate the fitness function of GA. To assess the validity and efficiency of the proposed method, several linear dipole arrays are designed to obtain scattering pattern with low sidelobe level (SLL). A good agreement between the patterns calculated using the expression and simulated by FEKO validates the accuracy of the presented expression. In addition, the numerical results show that the maximum SLL of the scattering pattern is considerably reduced by optimization. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2011.     

机载异类传感器模糊航迹关联算法的研究

机载雷达和电子对抗测量(ESM)已经成为机载平台上获取目标信息的重要传感器,它们之间的数据关联是典型的异类传感器数据关联问题,以往对于关联判别函数的选取,大多是基于方位角信息和统计方法建立判别函数,当目标密集或杂波较强的情况下,往往出现关联不稳定和关联正确率不高的情况.考虑到航迹关联判决中各因素的不确定性,提出使用基于角度和属性信息建立的模糊综合判别函数来解决机载雷达和ESM的航迹关联问题,通过建立适用于机载雷达和ESM特点的各种数学模型,解决了机载异类传感器航迹相关问题.仿真结果表明:该方法具有较低的漏关联概率和错误关联概率,能很好地解决机载雷达与ESM航迹关联问题.     

雷达视频回波信号实时采集、压缩转发装置

介绍了一种基于FPGA和DSP的六通道雷达视频回波实时信号采集、压缩转发装置,该装置单通道采样率为20MSPS,采样精度为12bit,采集后的数据经过DSP压缩处理后再转化为2Mbps的PCM码流,实时发送给遥测发射机进行遥测下传和实时检测;并对相位一致性控制、基于流水线的数据处理方法等关键技术做了详细介绍;该装置已成功应用于某飞行器综合匹配试验,其性能和指标均优于应用要求。     

基于ARM920T内核的雷达测速仪设计与算法研究

为了提高目前公路交通中对车辆速度的监测手段,提出一种基于ARM(advanced RISC machines)的新型雷达测速仪,结合多普勒测速原理和信号处理的谱估计法,介绍了由毫米波多普勒收发前端和SamsungS3C2410A处理器构成的雷达测速仪的整体设计,包括其硬件结构的设计和在ARM920T内核中实现基4时间抽取的快速傅里叶变换算法(fastFouriertransform,FFT)。实验结果表明,该雷达测速仪的测速精度可达±1km/h,其优化后的FFT算法具有很高的精度和运行效率。     

基于TS201系列DSP的PGA算法实现

相位梯度自聚焦(PGA)算法被广泛用于机载合成孔径雷达(SAR)成像中.由于其过程复杂,数据处理量大,为满足机载SAR实时处理的要求,选用具有强大处理能力的TS201 DSP.为了充分发挥TS201的性能,利用PGA原理和TS201处理器的特点,对算法流程进行优化,并且对最耗时的FFT采用了汇编语言实现,使得运算量和处...