PARASOL (Polarization & Anisotropy of Reflectances for Atmospheric Sciences coupled with Observations from a Lidar) launched by CNES on Dec. 18, 2004 is one of the French-U. S. satellite project called“A-Train”. It is carrying a wide-field imaging radiometer/polarimeter called POLDER (Polarization and Directionality of the Earth’s Reflectances)which could collect the directionality and polarization of light reflected by the earth and atmosphere. The information of surfaces, clouds and aerosols derived from the measurements is needed to improve the climate numerical model. The research progress on remote sensing from satellite multispectral, multidirectional and polarized measurements is summarily reviewed in this paper, especially for the POLDER in strument.
Some new methods, included satellite thermal IR anomaly, earthquake cloud, double magnetic storm time method, the abnormal superimposition of tide-generating frce resonance and so on, are introduced. Then this paper interprets their mechan isms and achievements respectively, their own advantages and disadvantages are also included at last. A break through is anticipated through the reinforcement and testification between these new methods and regular methods in earthquake forecast.
A numerical simulation is conducted to analyze a parabolic cylinderical reflector antenna with 7-half-wave-dipole array as feeder using the method of moments ( MoM) . The influence of offsetting the feeding array from the focal line is numerically studied. Results show that minus or plus offetting of feeder along the radial direction induce different effects both on the pattern and on the input impedance. Results also show that different diameter of dipoles impact much more on the input impedance than on the radiation pattern. Beam steering is also simulated.
The article focuses on the detection of the ’dangerous space debris’with diameter from 5mm to 7cm. The small, high-speed debris around the low earth orbit are damage to the satellites and the spacecrafts. By analyzing the critical technologies about space borne detection of the dangerous space debris the article put forward a millimeter wave phased-array radar system and the 35 GHz radar system is designed.
This paper gives a thorough study on geometric rectification of scanned to pographic map. There are many distortions caused by some reasons in scanned topographic maps. So they must be rectified before we use them. To reduce distortions effectively, the method of triangulation with grid points could be used usually for geometric rectification and lots of control points are required. But it' s too hard to extract grid points manually. In order to identify all grid points automatically , a novel geometric rectification algorithm of scanned topographic map is presented in this paper , which is based on the improved hought ransform.At first, we calculate the initial positions of grid points approximately using information of topography map, and make a “十”shape search area around each grid predicted point . And then, hough transform is used to detect grid lines in every search area and the intersections of grid lines are calculated. Finally, themap is rectified triangularly by affine transform, with intersections detected by hough transform as reference point s. Experimental results have showed that this method had the high precision performance to realize the sub-pixel precision extraction of grid points and no need to find reference points one by one manually . And it's also faster than traditional manual method.
The basic premise of hyperspectral data classification is that the spectral features of various materials are different from each other. With the development of sensor technology , hyperspectral sensor can collect in as many as several hundreds spectral bands at once. The hyperspectral data, which features high spectral resolution, also brings great difficult ies to classification. Because of the high dimension of data, great confusion and limited samples, the performance of traditional algorithms in hyperspectral data classification is deteriorated. In this paper a new combined algorithm based on independent component analysis( ICA) and neural network is proposed. Firstly, the independent component analysis algorithm is
used for feature abstraction. The spectral features are assumed to be a linear mixture of constituent spectra from the material types. The independent components are informative for classification, meanwhile the number of independent components is much smaller than the bands of original data. Then the multi-layer feed-forward neural network is used for classification. The spectral features of each pixel are used to be the input vector of neural network. The neural network is trained by Levenberg-Marquardt back-propagation ( LMBP) algorithm. The classification precision is remarkably superior to that of the conventional bayes classsifier. It proves by the experiment upon the 220-band hyperspectral data that the performance of this
combined algorithm is satisfying .
The affection of enhancing the spatial resolution of microwave radiometer images with traditional BG inversion theo ry is finite. In this paper, a new method—— subdivided reconstruction which improves BG inversion method to further enhance the spatial resolution is presented. The similarities and differences between this new method and the traditional method are compared in detail. A validation procedure is performed to demonstrate the effectiveness of this new method by using aynthetic image without considering the system errors.
Synthetic Aperture Radar is an efficient method of remote sensing. In the real-time processing system of Synthetic Aperture Radar, the high-speed data transmission is the emphases and the difficulty all the while. Aiming at the Rocket IO Tranceiver module of Xilinx Virtex2Ⅱ PROFPGA , This paper designs a high-speed serial I/O PCB board used on SAR data transmission system. This board uses Rocket IO module in the chip fully, BREFCLK differential input reference clock, 8B/10B recoder and pre-emphasis technology etc; implements one Rocket IO transmission at 3. 125 Gb/s and multi-channel high-speed serial in terconnection. It is reliable through validated by actual system. The results of simulation and experimentation on the hardware circuit prove this method is efficien t. and can reduce the design’s complexity and board size very well.
On the assumption that air temperature approximately equal to canopy temperature of dense vegetation and the negat ive linear relation between NDVI and LST in a 13×13 window , Prihodko and Goward ( 1997) estimate LST when NDVI= 0. 86 as Ta. In this paper, we first estimated the air temperature at the time of Terra satellite passing through from the maximum and minimum Tameasured from meteorological station with Parton &Logan model and took it as“true air temperature”. The relation
between NDVI, LST and “true air temperature ”were analyzed to verify the two assumptions that Prihodko and Goward used. The following conclusion were reached: ① In nigh t, the relationship between LST and NDVI cannot be identified but the air temperature can be represented by LST obtained from satellite approved by variance analysis; ② In day, the negative linear correlation between NDVI and LST can be observed in a plain when NDVI has a wide range. But the relation between NDVI and LST can’t be defined in the Qingzang plateau which has a complex topographty and in desert which has a very narrow NDVI range; ③In day, “t rue air temperatu re”are smaller than L ST in the p ixels w ith low NDV I because of the higher soil background temperature. But when NDVI> 0. 7, there was no difference between“true air temperature”and LST statistically. Based on results ② and ③, the method proposed by Prihodok &Goward for air temperature reversion from remote sensing has some limits when used in regional scale especially in desert and mountainous region.
Remote sensing technique has being widely used in drought inspection. Aiming at temperature/vegetation drought index ( TVDI) method, using NOAA/ AVHRR data, the spatial phenophase difference caused by the latitude, topography of underly ing surface in the large-scale drought inspection was reported, which showed the necessity of zonal calculation of drought index . By the calculation in difference latitude, the area of surface temperature-vegetation index space is reduced, which improved the accuracy of equations of drought line and wetline. Comparison of the relationship between temperature/egetation
drought index ( TVDI) obtained from the zonal calculation and whole calculation respectively and the measured soil relative humidity of 10cm, 20 cm, 50 cm showed that , in the zonal calculation, the relativity between temperature/ vegetation drought index ( TVDI) and the soil relative humidity in different depth was evidently improved, which increased the veracity of drought inspection in larg e-scale using remote sensing.
Normalized Difference Vegetation Index (NDVI) is one of the earliest vegetation indices that have been widely used in vegetation remote sensing. It can respond to changes in amount of green biomass,chlorophyll content, and canopy water status etc. However, NDVI value might not reflect the truth of vegetation canopy because it is disturbed intensively by soil background and other factors. In this study,the effect of soil background on canopy NDVI was analyzed by measured soil data, theoretic derivation and PROSAIL model simulation. First, we supposed that a vegetation canopy with horizontally distributed
leaves was linearly mixed with soil background, the influences of soil backgrounds on NDVI in different vegetation coverages were analyzed according to the equation based on red reflectance, near-IR reflectance of soils and vegetations, and vegetation coverages. Second, the influence of soil background on NDVI in different LAI was simulated and analyzed by PROSAIL model. The results indicated: ①the influence of soil backgrounds was larger when LAI was small, and the canopy NDVI with a dark soil background was bigger than it with a bright soil background. ②NDVI with a dark soil background was more sensitive to the change of soil brightness, but the canopy NDVI with a bright soil background was more sensitive to the change of LAI or vegetation coverages. Finally, the results were validated using measured wheat canopy spectrum data in different soil backgrounds.
According to the growing synchronizations of winter wheat, the growing average status, the soil types and the irrigation conditions, etc, referring to Hebei recent land-using data and ecological regionalization result, this paper devides the planting environment of winter wheat into five parts in Hebei province. On this basis, with the use of multi-temporal MODIS data and spot GPS location information, fully considering the growing characteristics of winter wheat and the surface vegetation, this paper finds out the non-winter wheat planting area's information in the growing season. When alculat ing the winter wheat's planting area and solving mixing pixels, this paper Improves the ratio of the wheat area and land into a new method w hich calculates the rat io of actual w heat plant ing area and tho se map ar ea of w heat
pixels. Combining the remote sensing knowledge, geographical knowledge and agricultural knowledge,making an system o f monito ring planting information, later we use this system to extract the winter wheat planting information during 2004～2005 period and give the total area statistic error of 3. 2% .
In remote sensing technology , it is difficult to extract residential information automatically from image because many buildings are made of different materials and the high-rise has shadow , furthermore,the buildings' roof made of mud have the same spectra character with some of the desert , in light of this,it made harder and harder to extract residential information from remote sensing image in arid and semiarid regions. It is great helpful to maintain the operation of desert-railway and desert-road, protect oasis if we clearly knowing the change information of the grass of shelter belt , but the gr ass of shelter belt have the similar spectra character with desert shrub because of the same kind of vegetation. Therefore the traditional auto-classification based on the spectral character always has poor accuracy because of the common existing of same object having different spectral character and different object having same spectral character especially in arid and semiar idregions. In this paper, we studied the spectral character of our study region in detail and based our classification system on the spectral character and our filed work. After supervised classification we extracted residential area and the grass of shelter belt based on knowledge discovery , finally we got the accuracy assessment report s. Experiment results show that the classification method based on multi-features has great accuracy compared with traditional autoclassification based on the spectral character.
This paper discusses about the extraction of urban green space from high resolution remote sensing image. Computation 30 green space samples using au tocorrelation function, the results shows that movement two pixels, the autocorrelation index is up to 0. 95, which to ensure texture window as 53 5.Based on panchromatic image grey cooccurrence at rix, selected 45°, 135°, 225°, 315°four directions means, computation five textu reparameter : Mean, variance, mogeneity, contrast, secondmoment.Applicability multi-resolution segmentation panchromatic image and five texture images, according green space five texture feature to select threshold of image objects that after segmentation, extraction green space information, after accuracy appraisal the right up to 92. 8%. The result indicated that the method adopted has good utility on extraction urban green space information from high resolution remote sensing image.
For to search new dataset, we study the application potential of IRS-P6 images in Landuse Dynamic Monitoring project. The resolution of IRS-P6 PAN image is 5. 8m. So it should can be used in this project. This paper tests some factors of IRS-P6, including the scale of cartography, the polygon area of response, the degree of recognising landtype, the precision of detecting information etc.Considering the demand of the project of landuse dynamic monitoring, the result indicates that IRS- P6 can be used to make a map of 1∶25 000 or 1∶50 000 and update or assistantly update 1∶25 000 or 1∶50 000 land use actuality map. In the landuse dynamic monitoring project, IRS-P6 image can be used as another dataset with LANDSAT and SPOT. So it can serve land management more rapidly.
Satellite remote sensing technology applied in the route selection of the high voltage transmission lines has the advantage that the normal method can’t compare to. In the study of the route selection engineering of the 500 kV high voltage direct current transmission lines in Ning-Meng-Shan subsection of northwest-north China, we acquired the relative information of geology, physiognomy and so on in the research district, and analyzed temporal evolution and distribution rule of sand dune and desertification along the route, according to processing multi-temporal images. The result suggests that the sand dune is characterized by semi-active dune, the move speed is very slow , and all round the district desertification show s negative increase. Especially we acquired the digital elevation model based on the contour element of the map and visually simulated dummy three-dimensional geography sight in the study area, also we obtained real three-dimensional surface sight by attaching and compounding the relative remote sensing image, which improved the visual impact. The article proposes two chemes of routing selection according to synthetically analyze landform, physiognomy, engineering geology, lithology,structure, geographical condition, the distributing of habitation and correlative factors based on the results of the processing which mentioned above. It provides the scientific ground for ultimately establishment of the scheme for routing selection on the high voltage transmission lines.
