فهرست مطالب

نشریه مهندسی نقشه برداری و اطلاعات مکانی
سال سوم شماره 2 (پیاپی 10، خرداد 1391)

  • تاریخ انتشار: 1391/03/01
  • تعداد عناوین: 7
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  • M. A. Sharifi, A. Safari, S. Masoumi Page 1
    In recent decades, with the advent of satellite and Ionospher impact on these satellites and their orbit, more attention has been Ionospher studies. This study reviewed various methods for measuring Ionospher advantages and disadvantages of each country. These methods include Ionosonde, Topside sounding, Incoherent Scatter Radar, Coherent Scatter Radar, the method of measuring In-situ, using Global Positioning System (GPS) ground station, and Radio Occultation.Also, the examples of ionospheric observation application are presented. Ionospher phenomena of the equatorial anomaly and half-yearly anomaly in Iran regions are shown with Radio Occultation. Among the methods, observations of GPS ground receivers and radio Occultation are known as the most appropriate methods.
    Keywords: Ionosonde, GPS, Radio Occultation, Anamoly
  • H. R. Ranjbar, A. R. Gharaghozlou, A. R. Vafaei Nejad Page 13

    The continuous improvement and application of computer technology is rapid changing the way the people manage their environments. With the sophisticated software in use, data acquisition is becoming the most expensive part of establishing a road network database. For this challenge, the mobile mapping systems have been developed to quickly and accurately collect road infrastructures. One of these systems is what we proposed in this research which integrates the Global Positioning System (GPS), an Inertial Navigation System (INS) and stereo cameras into a moving platform. This system captures the images of road environment while its position and orientation are provided by the GPS/INS. After the system is calibrated, every visible feature which is seen from two images can be located in a global coordinate system. This system has been implemented in parts of Golestan roads and also a software provided for managing outputs in an optimal way. The capabilities of the system could be developed by using other sensors like Laser.

    Keywords: Mobile Mapping, GPS, INS
  • R. Zarei, M. R. Sarajian, S. Bazgeer Page 25

    Natural, very complex phenomena drought is a disaster with impact on the economy, agriculture, human activities, wildlife and the overall on vegetation. Large-scale droughts in recent years have been found in all continents. Drought index obtained from meteorological data, have not good temporal and spatial resolution. These indicators have not good accuracy and can be used only for a specific area. Moreover, these indicators cannot be updated drought monitor. Remote sensing data provided an appropriate regulatory tool to assess the severity of drought. Growth rate of vegetation is one of the most important indicators of the occurrence of drought. In this study, the evaluation of a number of plant parameters is presented and finally, the NDVI index has been chosen as a suitable index for the vegetation. After introducing several drought indicators such as VCI, TCI, VHI and the DSI will be extracted from satellite images, have been studied.E of these indicators can be used in a specific time and place.

    Keywords: drought, NDVI, Satellite Imagery
  • H. Masoumi, F. Alidoost, K. Seidi, S. Taghi Zadeh Page 35

    Unmanned aerial vehicles have important role in military and civilian programs in several countries. One of the important aspects of these vehicles is the ability of tracking and positioning them in the various operational conditions in order to automated navigation. For this, many types of Satellite Positioning System receivers are used for tracking vehicles or in combination with an automatic guidance system for guiding them. This study is a brief explanation on how to measure the position of the unmanned aerial vehicles using Satellite Positioning System receivers. The physical properties of these receivers and their technologies in terms of traceability of satellite systems, the ability to track a variety of radio frequencies and positioning accuracy are also studied. The results show that in many real time UAV applications, the high accuracy of position is not necessary, and the accuracy up to several meters is acceptable. Using of the multi frequency receivers is more appropriate for positioning of these vehicles. These receivers are compact and low power, and are perfectly suited for applications where size constraints, weight and minimal power consumption are critical, such as in helicopter cockpits or for UAV applications.

    Keywords: Unmanned Aerial Vehicle, Satellite Positioning System Receiver, Global Navigation Satellite System
  • H.Mohammadi, F. Dadrasjavan, A.Fallah Page 49

    Considering ongoing developments in Photogrammetry and Remote Sensing and attending to their applications such as digital true orthophoto generation from multi view and high resolution images, have already proven the urgency and necessity of approaches for generating DSM as input of these applications. In this research we describe the “Semi-Global Matching” algorithm and then implement and test if for generating an initial disparity image from airborne UltraCameD images. SGM uses a pixelwise, Mutual Information based matching cost compensating radiometric differences of input images. Pixelwise matching is supported by a smoothness constraint that is usually expressed as a global cost function. SGM performs a fast approximation by pathwise optimizations from all directions. Furthermore, post-processing steps for removing outliers, recovering from specific problems of structured environments and the interpolation of gaps are needed, to generate an accurate and precise DSM in the next steps for other applications.

    Keywords: Semi, Global Matching, Stereo images, Disparity image, Cost function, Multi, baseline matching
  • M. Davodi Jam, M. Motagh, M. Momeni, M. Hashemi Page 69
    In recent years, because of population growth and water shortages due to global warming, groundwater use in agriculture, industry and households has been growing. This is one of the main causes of subsidence occurred in Iran. To study this phenomenon, some approaches such as GPS and geodetic leveling can be used. But the study of this phenomenon becomes easier by using InSAR technique. Using this technique, the displacement in the region field without the need for large working, with high precision, and with less expenditure can be observed. In this report, in temporal and spatial changes subsidence in Mahyar of Isfahan is studied. About 30 years ago in the plains and rift-related subsidence has been observed that the deformation of serious damage to agricultural land, roads and constructional. .. is followed. For that, 15 images of InSAR of ENVISAT within the period 2006-2003 with short base (SBAS) method were used. This method is provided subsidence map. Base on result, there is an 8.6 cm of subsidence in Mahyar.
    Keywords: SAR, Radar Interferometry, SBAS, subsidence, Mahyar Plain