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901.
Vinod K. Hanna M. S. Ravichandran S. P. S. Kushwaha 《Journal of the Indian Society of Remote Sensing》2001,29(1-2):41-46
This paper deals with corridor analysis in Rajaji-Corbett Elephant Reserve in the Shivaliks of Uttaranchal state. Efforts were made to detect changes in the state of forest covervis- à -vis the status of corridors during the three periods i.e. 1967. 1986 and 1998 using remote sensing and GIS. TheERDAS Imagine digital image processing andArcView GIS software packages were used for this purpose. Temporal satellite imagery and ground observations in the Rajaji-Corbett Elephant Reserve revealed forest loss, degradation and disturbances in the corridor areas, hindering elephant movement and restricting them to forests islands. Motichur-Chilla corridor, despite being a highly favoured habitat for the elephants was found to be highly threatened followed by Kotdwar and Ramnagar corridors. Construction of wide bridges across Kunao-Chilla Canal, recreation of corridors through reforestation, reduction of all kinds of pressures in the corridor areas and providing higher protection to corridors are recommended. 相似文献
902.
903.
904.
Doug Hunt 《GPS Solutions》2000,4(1):74-76
The GPS Toolbox is dedicated to highlighting algorithms utilized by GPS engineers and scientists. If you have an interesting
algorithm you would like to share with our readers or if you have a topic you would like to see covered in a future column,
contact us at gps-toolbox@ngs.noaa.gov. To comment on the algorithms presented here, or to leave a request for an algorithm
you may be looking for, visit our Web site (http://www.ngs.noaa.gov/gps-toolbox). ? 2000 John Wiley & Sons, Inc. 相似文献
905.
In recent years the importance of real-time positioning and navigation with the Global Positioning System (GPS) has grown
rapidly. Starting from the establishment of differential GPS (DGPS) reference stations for marine and land navigation, new
users and applications have emerged that resulted in a high demand for the establishment of a high-density network of reference
stations around the world. Many countries have established their own DGPS service, which is either governmentally or commercially
owned. These services are referred to as Local Area DGPS Systems (LADGPS). However, the costs for the establishment and maintenance
of a dense network of reference stations are very high. Therefore Wide Area DGPS Systems (WADGPS) are being developed to overcome
the main drawbacks of LADGPS. In this case, only a few reference stations are used to cover a large area, such s a continent
like Europe. To achieve high positioning accuracies, real-time modeling of the main error sources for long-range baselines
is required as errors in the satellite orbit and ionospheric refraction do not cancel entirely in double differencing. In
this article, a real-time correction model based on the Kalman filter for WADGPS and networked LADGPS services is discussed
and results of field tests in a WADGPS network in Europe are presented. ? 2000 John Wiley & Sons, Inc. 相似文献
906.
DGPS and RTK Positioning Using the Internet 总被引:1,自引:0,他引:1
Hisakazu Hada Hideki Sunahara Keisuke Uehara Jun Murai Ivan Petrovski Hideyuki Torimoto Seiya Kawaguchi 《GPS Solutions》2000,4(1):34-44
The Internet as a basis for Real-Time Kinematic (RTK) and differential Global Positioning System (DGPS) service provides many
advantages for worldwide GPS users. Among these advantages are service unification, open architecture, bidirectional communication,
and scalability. The current development of this service allows users to use RTK and DGPS through the Internet with conventional
accuracy over the short and medium baselines. The perspective for this service lies in the field of wide-area augmentation
systems (WASS). At this stage of the Internet-based RTK and DGPS service project, the general concept, system components,
draft standards, and software are developed. ? 2000 John Wiley & Sons, Inc. 相似文献
907.
Günter W. Hein 《GPS Solutions》2000,3(4):39-47
Positioning and navigation – as are presently possible with the American Global Positioning System (GPS) and the Russian GLONASS
system – is briefly reviewed. Deficiencies, which have led to augmentations like the European Geostationary Navigation Overlay
System (EGNOS), are outlined. Europe's decision to get involved in the definition and possible set-up of a Global Navigation
Satellite System (GNSS) of the second generation (GNSS-2), called Galileo, is discussed in detail as well as the GPS modernization
program that might take place during the sample phase. Finally, some brief thoughts on the benefit of GNSS-2 for geodesy and
surveying are given. ? 2000 John Wiley & Sons, Inc. 相似文献
908.
The success rate and precision of GPS ambiguities 总被引:7,自引:1,他引:7
P. J. G. Teunissen 《Journal of Geodesy》2000,74(3-4):321-326
An application of a theorem on the optimality of integer least-squares (LS) is described. This theorem states that the integer
LS estimator maximizes the ambiguity success rate within the class of admissible integer estimators. This theorem is used
to show how the probability of correct integer estimation depends on changes in the second moment of the ambiguity `float'
solution. The distribution of the `float' solution is considered to be a member of the broad family of elliptically contoured
distributions. Eigenvalue-based bounds for the ambiguity success rate are obtained.
Received: 11 January 1999 / Accepted: 2 November 1999 相似文献
909.
In the present study analysis of Landsat MSS, TM and SPOT imagery and digital analysis of IRS LISS-1 data of Doon Valley was carried out. Various geomorphic features were identified and classified, morphostratigraphy of the area has been established. Main geomorphic units of the area are Mussoorie Hill Range (Denudational), Siwalik Hills (Structural), Remnant Hills (Residual). Siwalik Piedmont. Doon Piedmont, River Terraces and Flood Plain. Three large fan lobes are identified on Doon Piedmont deposits, viz., Western fan lobe, Central fan lobe and Eastern fan lobe. Average slope of these three fan lobes are 2°21′, 2°3′, and 1°24′ for the western, central and eastern fan lobes respectively. Western and central fan lobes have been affected by neotectonic activity which is reflected in transverse profiles. 相似文献
910.
S. Panigrahy M. Chakraborty K. R. Manjunath N. Kundu J. S. Parihar 《Journal of the Indian Society of Remote Sensing》2000,28(1):59-65
Radarsat ScanSAR Narrow (SN2) data acquired on July 24 and August 17, 1997 were used to analyse the signature of rice crop in West Bengal, India. The analysis showed that the lowland practice of cultivation gives a distinct signature to rice due to the initial water background. The relatively stable backscatter from water bodies in temporal data enhanced the separability of rice fields from water using two date data. Around 94 per cent classification accuracy was achieved for rice crop using two date data. It was feasible to discriminate rice sub-classes based on their planting period like early and late crop. The analysis indicates the suitability of ScanSAR data for large area rice crop monitoring as it has a wide swath of 300 km. 相似文献