一种用于雷达量测的滤波算法

在雷达跟踪系统中 ,广泛使用混合坐标系下扩展卡尔曼滤波器 (EKF)和转换卡尔曼滤波器 (CMKF)两种算法。但是当目标距离较远时 ,这两种滤波器由于量测方程非线性的影响 ,误差较大 ,甚至导致滤波发散。本文计算了传统 EKF滤波器引入的线性化误差 ,并在此基础上提出一种新的滤波算法 (NDRKF)。计算机仿真结果表明 ,该算法减小了线性化误差的影响 ,较明显地改善了滤波器的性能。

基于雷达量测的多普勒速度计算方法研究

环境恶劣的时候,雷达探测目标会产生大量的虚警杂波点,这会导致目标跟错的现象。为了能正确跟踪目标,就需要在航迹关联或者起始时,排除虚警杂波点,关联真实目标点迹。在现代脉冲多普勒体制雷达中,雷达可以测量得到很准确的目标径向速度信息。在航迹关联或者起始时,可以利用当前点迹的多普勒速度与利用当前探测点迹和上个时刻探测点迹位置计算出来的径向速度的相关性,来抑制虚警杂波点,从而提高航迹相关或者起始的准确度。于是,本文描述了三种利用前后点迹量测位置信息来计算当前点迹多普勒速度的方法并进行了比较。

基于修正无偏转换测量的交互式多模型算法

雷达系统中的目标跟踪技术不仅需要从噪声中将能够直接测量得到的信号提取出来,估计出不能直接测量的诸如目标加速度等信息;而且还要处理从球坐标系到笛卡尔直角坐标系下量测的非线性转换。针对此问题,本文提出了集交互式多模型和修正的无偏转换测量两者优点的IMM-MUCMKF跟踪算法。理论分析和仿真结果表明,本算法的跟踪性能要优于集交互式多模型和不敏卡尔曼的IMM-UKF算法。

基于迭代最近点的雷达非均匀分布系统误差校正方法

雷达系统误差配准是雷达组网的前提和基础,对于探测距离远的雷达,其在探测空间内的测量误差呈现明显的非均匀分布特性,导致传统的系统误差校正方法难以满足误差校正需求。针对雷达系统误差存在的非均匀分布特性,将雷达探测空间分成若干小区域,每个小区域可以认为系统误差为定值,此时,可在每个区域内利用迭代最近点算法计算该区域中的雷达系统误差,形成全探测空间内的系统误差补偿矩阵,从而实现对非均匀分布系统误差的准确校正。最后,通过实测数据实验验证了提出方法的有效性。

基于UIMMS的多站雷达机动目标跟踪研究

针对多站雷达量测机动目标跟踪问题,提出了一种将平滑方法运用于典型的交互式多模型结构的跟踪算法。首先介绍了卡尔曼平滑器(KS),比较了不敏卡尔曼滤波(UKF)和不敏卡尔曼平滑(UKS)两种方法,引入并分析比较了IMMF和IMMS方法。同时,针对目标机动特性以及多雷达量测带来的非线性等问题,构造了多部雷达跟踪机动目标场景,进行了典型方法的比较和新方法的验证,实验结果验证了新方法的有效性。

用多任务雷达和光学传感器进行目标跟踪的异步数据融合

本文研究了融合来自两个不同传感器的异步数据的技术,其中一个传感器以比另一个传感器高的速率提供数据。目的是:当用另一个传感器观察时,同时获得高数据率传感器数据的最小二乘法估计。先前研究的同步数据融合算法被用来融合时间一致的数据以更新目标状态估计。考虑了融合来自光学传感器和雷达数据的情况,其中,光学传感器以高速率提供周期性数据而雷达以低数据速率提供拟周期数据。通过提供类似于由际准序次数据处理方法所得的结果的仿真,证明了利用这种数据融合方法的跟踪滤波器的性能,这种标准的序次数据处理方法需要更多的有效计算。

一种航路模拟软件的工程实现方案

本文在三种基本运动模型的基础上,研究并建立了建立三种目标机动运动的状态-空间模型:蛇形机动、俯冲机动、上仰机动。提出了一种在 VPX 单板计算机上航路模拟软件的实现方案,该方案可以产生同时多个不同类型、不同运动方式目标的航迹数据,并加入量测噪声和杂波、进行方位、距离单元扩展,实时输出模拟雷达量测信息。

Analysis of Physical Quantities and Radar Parameters about Hail Shooting and Heavy Convective Rainfall

[Objective] The paper is to analyze physical quantities and radar parameter of hail shooting and heavy convective rainfall weather. [Method] Using radar data of Jinan station during 2002 and 2008, combined with sounding data, the physical quantities and radar parameter of hail shooting and heavy convective rainfall weather are compared and analyzed. [Result] The smaller Sl is conducive to the generation of hail weather. When K〉 35 ~C, the probability for occurrence of heavy rainfall weather is significantly increased; when K〈20 ^（3, the probability for occurrence of heavy rainfall weather is significantly decreased. When CAPE value is greater than 1 500 J/KG, the probability for occurrence of hail weather is significantly decreased, while the probability for occurrence of heavy rainfall weather is significantly in- creased. The possibility for occurrence of hail monomer is small when the wind shear is less than 5 m/s; and it is large while wind shear is greater than 20 m/s. The radar forecasting indexes of hail monomer is as follows： VIL value reaches 35 kg/m2 （May）, 43 kg/m2 （June and July）, the monomer height is greater than 9 km, the maximum reflectivity factor is larger than 60 dBz, strong center height reaches 3.3 km （May）, 4.3 km （June） and 5.5 km （July）; VlL value of heavy rainfall monomer generally is below 25 kg/m2. [Conclusion] The paper provides basis form prediction of hail and heavy rainfall.

Adaptive Filter in SAR Interferometry Derived DEM

In this paper, the performance of median filter, elevation dependent adaptive sigma median filter, and directionally dependent adaptive sigma median filter are tested on both InSAR Tandem DEM and simulated high-level noisy DEM. Through the comparison, the directionally dependent adaptive sigma median filter is proved to be the most effective one not only in the noise removing but also in the boundary preserve.

Measurements of ocean wave and current field using dual polarized X-band radar

A new ocean wave and sea surface current monitoring system with horizontally-(HH) and vertically-(VV) polarized X-band radar was developed.Two experiments into the use of the radar system were carried out at two sites,respectively,for calibration process in Zhangzi Island of the Yellow Sea,and for validation in the Yellow Sea and South China Sea.Ocean wave parameters and sea surface current velocities were retrieved from the dual polarized radar image sequences based on an inverse method.The results obtained from dual-polarized radar data sets acquired in Zhangzi Island are compared with those from an ocean directional buoy.The results show that ocean wave parameters and sea surface current velocities retrieved from radar image sets are in a good agreement with those observed by the buoy.In particular,it has been found that the vertically-polarized radar is better than the horizontally-polarized radar in retrieving ocean wave parameters,especially in detecting the significant wave height below 1.0 m.

A Case Study of Using External DEM in InSAR DEM Generation

Synthetic aperture radar interferometry (InSAR) has been used as an innovative technique for digital elevation model (DEM) and topographic map generation. In this paper, external DEMs are used for InSAR DEM generation to reduce the errors in data processing. The DEMs generated from repeat-pass InSAR are compared. For steep slopes and severe changes in topography, phase unwrapping quality can be improved by subtracting the phase calculated from an external DEM. It is affirmative that the absolute height accuracy of the InSAR DEM is improved by using external DEM. The data processing was undertaken without the use of ground control points and other manual operation.

SELECTION OF BRILLOUIN SHIFT DISCRIMINATOR FOR BRILLOUIN LIDAR

For the measurement of vertical profiles of sound speed in the sea using laser excited Brillouin scattering, a high resolution measurement of Brillouin frequency shift is required. In this work, a molecular absorption cell was selected as the frequency shift discriminator and several kinds of absorption gases were tried. It was found that the strong line (#1095) of 127 I 2 at 18783.3297 cm -1 and two absorption lines of 129 I 2 located at the two sides of the #1095 line of 127 I 2 could be used as frequency shift discriminator to detect the changes of the Brillouin frequency shift. This selection is the best one within the range from 532.0131 nm to 532.5154 nm. But it is not perfect and there is a lot of work to do before its practical application.

Laser diode drive method with narrow-width and high-peak current for multi-line LIDAR

Light detection and ranging (LIDAR) based on time of flight (TOF) method is widely used in many fields related to distance measurement. LIDAR generally uses laser diode (LD) to emit the pulsed laser with high peak power and short duration to ensure a large distance measurement range and eye safety. To achieve this goal, we propose a pulsed LD drive method producing the drive current with high peak and narrow pulse width. We analyze the key issues and related theories of the drive current generation based on this method and design an LD driver. A model of drive current generation is established and the influence of operating frequency on drive current is discussed. The LD driver is simulated by software and verified by experiments. The working frequency of the driver changes from 20 kHz to 100 kHz and the charging voltage is set at 130 V. The current produced by this driver has a duration of 8.8 ns and a peak of about 35 A, and the peak output optical power of the LD exceeds 75 W.

A quantitative analysis method for GPR signals based on optimal biorthogonal wavelet

Due to the disturbances arising from the coherence of reflected waves and from echo noise,problems such as limitations,instability and poor accuracy exist with the current quantitative analysis methods.According to the intrinsic features of GPR signals and wavelet time–frequency analysis,an optimal wavelet basis named GPR3.3 wavelet is constructed via an improved biorthogonal wavelet construction method to quantitatively analyse the GPR signal.A new quantitative analysis method based on the biorthogonal wavelet(the QAGBW method)is proposed and applied in the analysis of analogue and measured signals.The results show that compared with the Bayesian frequency-domain blind deconvolution and with existing wavelet bases,the QAGBW method based on optimal wavelet can limit the disturbance from factors such as the coherence of reflected waves and echo noise,improve the quantitative analytical precision of the GPR signal,and match the minimum thickness for quantitative analysis with the vertical resolution of GPR detection.

Initial Results of Lidar Measured Middle Atmosphere Temperatures over Tibetan Plateau

During August 2013,a mobile Rayleigh lidar was deployed in Lhasa,Tibet(29.6°N,91.0°E) for making measurements of middle atmosphere densities and temperatures from 30 to 90 km.In this paper,the authors present the initial results from this scientific campaign,Middle Atmosphere Remote Mobile Observatory in Tibet(MARMOT),and compared the results to the MSIS-00(Mass Spectrometer and Incoherent Scatter) model.This work will advance our understanding of middle atmosphere dynamic processes,especially over the Tibetan Plateau area.

Use of SAR interferometry for monitoring illegal mining activities: A case study at Xishimen Iron Ore Mine

The development and application of the ''digital mine'' concept in China depends heavily upon the use of remote sensing data as well as domestic expertise and awareness. Illegal mining of mineral resources has been a serious long term problem frustrating the Xishimen Iron Ore Mine management. This mine is located in Wu'an county in Hebei province, China. Illegal activities have led to enormous economic losses by interfering with the normal operation of the Xishimen mine and have ruined the surrounding environ- ment and the stability of the Mahe riverbed the crosses the mined area. This paper is based on field recon- naissance taken over many years around the mine area. The ground survey data are integrated with Differential Synthetic Aperture Radar Interferometry (D-InSAR) results from ALOS/PALSAR data to pin- point mining locations. By investigating the relationship between the resulting interferometric deforma- tion pattern and the mining schedule, which is known a priori, areas affected by illegal mining activities are identified. To some extent these areas indicate the location of the illegal site. The results clearly dem- onstrate D-InSAR's ability to cost-effectively monitor illegal mining activities.

Two-sided Long Baseline Radargrammetry from Ascending Descending Orbits with Application to Mapping Post-seismic Topography in the West Sichuan Foreland Basin

One-sided ascending or descending Synthetic Aperture Radar（SAR） stereoradargrammetry has limited accuracy of topographic mapping due to the short spatial baseline（-100 km） and small intersection angle. In order to improve the performance and reliability of generating digital elevation model（DEM） from spaceborne SAR radargrammetry, an exploration of two-sided stereoradargrammetry from the combination of ascending and descending orbits with geometric configuration of long spatial baseline（-1000 km） was conducted in this study. The slant-range geometry between SAR sensors to the earth surface and the Doppler positioning equations were employed to establish the stereoscopic intersection model. The measurement uncertainty of two-sided radargrammetric elevation was estimated on the basis of radar parallax of homogeneous points between input SAR images. Two stereo-pairs of ALOS/PALSAR（Advanced Land Observing Satellite/Phased Array type L-band Synthetic Aperture Radar） acquisitions with the orbital separation almost 1080 km over the west Sichuan foreland basin with rolling topography in southwestern China were employed in the study to obtain the up-to-date terrain data after the 2008 Wenchuan earthquake that hit this area. Thequantitative accuracy assessment of two-sided radargrammetric DEM was performed with reference to field GPS observations. The experimental results show that the elevation accuracy reaches 5.5 m without ground control points（GCPs） used, and the accuracy is further improved to 1.5 m with only one GPS GCP used as the least constraint. The theoretical analysis and testing results demonstrate that the twosided long baseline SAR radargrammetry from the ascending and descending orbits can be a very promising technical alternative for large-area and high accuracy topographic mapping.

Research on Radar Emitter Attribute Recognition Method

In order to solve emitter recognition problems in a practical reconnaissance environment, attribute mathematics is introduced. The basic concepts and theory of attribute set and attribute measure are described i n detail. A new attribute recognition method based on attribute measure is prese nted in this paper. Application example is given, which demonstrates this new me thod is accurate and effective. Moreover, computer simulation for recognizing th e emitter purpose is selected, and compared with classical statistical pattern r ecognition through simulation. The excellent experimental results demonstrate t hat this is a brand-new attribute recognition method as compared to existing st atistical pattern recognition techniques.

A new modulation transfer function for ocean wave spectra retrieval from X-band marine radar imagery

When imaging ocean surface waves by X-band marine radar, the radar backscatter from the sea surface is modulated by the long surface gravity waves. The modulation transfer function （MTF） comprises tilt, hydrodynamic, and shadowing modulations. A conventional linear MTF was derived using HH-polarized radar observations under conditions of deep water. In this study, we propose a new quadratic polynomial MTF based on W-polarized radar measurements taken from heterogeneous nearshore wave fields. This new MTF is obtained using a radar-observed image spectrum and in situ buoy-measured wave frequency spectrum. We validate the MTF by comparing peak and mean wave periods retrieved from X-band marine radar image sequences with those measured by the buoy. It is shown that the retrieval accuracies of peak and mean wave periods of the new MTF are better than the conventional MTF. The results also show that the bias and root mean square errors of the peak and mean wave periods of the new MTF are 0.05 and 0.88 s, and 0.32 and 0.53 s, respectively, while those of the conventional MTF are 0.61 and 0.98 s, and 1.39 and 1.48 s, respectively. Moreover, it is also shown that the retrieval results are insensitive to the coefficients in the proposed MTF.

Chinese Surveying and Control Network for Earth-Orbit Satellites and Deep Space Detection

The relationship between the surveying and contro l network(CSN) for earth-orbit satellite and spatial geodesy, and the relationshi p between the CSN for deep space celestial bodies and detectors, and deep space detection are briefly summarized, and so are the basic technical needs of the de ep space surveying and control network(DSN). Then, the techniques, the constitue nts and the distributing of Chinese satellite CSN (CSCSN) and other radio observ ing establishments in China are introduced. Lastly, with the primary CSCSN and o ther observing establishments, some projects for China to rebuild a more perfect CSCSN, and to establish a DSN are analyzed and stated.