Articles in the Articles Category

Nov 2005 | Comments Off on Signal propagation through the troposphere


Space environmental effects on satellite communication can be considered as related to space segment, ground segment and on the signals propagating through the earth’s lower and upper atmosphere. The atmospheric structure has significant influence on signal propagation. This has definite influence on the data processing methodologies. The specific applications with which are concerned here are …

Nov 2005 | Comments Off on JAMFEST, A cost effective solution to GPS vulnerability testing

The 746th Test Squadron (746 TS) has conducted complex GPS jamming experiments since the early 1990s and played a key role “behind the scenes” creating multiple high-profile jamming environments for programs such as the Joint GPS Combat Effectiveness (JGPSCE) exercises and Quick Reaction Tests. These programs, conducted to support real-world operations, enhanced the 746th TS’s ability to recreate realistic jamming environments and resulted in the 746 TS earning the reputation as the recognized experts for open-air GPS vulnerability testing.

Nov 2005 | Comments Off on MARK YOUR CALENDAR

November 2005


International Conference: “Earth Observation foaterr vegetation …

Nov 2005 | Comments Off on Indoor positioning in wireless

Recently mobile location based services (LBS) are provided via a mobile terminal such as a personal digital assistant (PDA), a cellular phone and so on. The location method that searches where the mobile terminal of a user is accurately is a key factor for providing convenient and useful LBS. The most well known method associated with positioning system is GPS. The signal of GPS satellites can be always acquired outdoors and this system provides comparatively accurate location information. However, there are difficulties in applying GPS directly to indoor positioning because of the weakness of signal. And the positioning using the mobile communication signal between a base station and a cellular phone does not provide adequate accuracy due to some technical limitations of communication systems when applied to navigation. In addition, severe multipaths are present in an indoor environment. So a new wireless communication technology is required for indoor positioning to achieve a better and appropriate accuracy. Wireless local area network (LAN) has been installed in a number of indoor areas such as office, terminal, campus, and park with interests in mobile Internet. Therefore, it is expected that a wireless LAN signal would be easily acquired for indoor positioning. Various positioning measurements like time of arrival (TOA), time difference of arrival (TDOA), and received signal strength may be employed for indoor positioning. Employing TOA or TDOA measurements requires a time synchronization between a transmitter and a receiver. But, a time synchronization between a transmitter and a receiver is very difficult if not impossible in a wireless LAN. Therefore, it is more appropriate to use signal strength for indoor positioning with a wireless LAN.

Nov 2005 | Comments Off on Innovations 1983 and 1996

Tidal Modeling for GPS Positioning –

In …

Oct 2005 | Comments Off on Building relationships

11th Technology summit strengthens Indo-Canadian relationship. 21-22 September 2005 New Delhi

The 11th Technology Summit and …

Oct 2005 | Comments Off on Make maps quickly

Seven out of ten customers of surveys and mapping who talk to the suppliers (consulting fi rms of surveying agencies) demand their maps to be delivered `yesterday’(!) or indeed as early as possible. These customers are `decision-makers’ who have taken some months (if not years) to come to the demand level! Same is the situation in respect of the tenders in mapping discipline. All the risks and uncertainties are put on the door of the suppliers / contractors. One should realize that although the surveying and mapping process never costs more than 1 or 2 percent of total budget, the same is not true when it comes to the time taken for the mapping project. The fact is that many projects are delayed just because the survey data of right quality and proper map was not made available to the engineer / planner.

Oct 2005 | Comments Off on CLASSROOM GEODESY

The Coordinates Class room espouse readers to graticules of Mathematics and Physics that epitomize the Geospatial Information Technology. A chain of structured presentations related to interdisciplinary principles that define Geodesy, GPS, GIS, Geospatial data management and Image processing are to be en suite in this section in each issue of the Coordinates. Initially the chain …

Oct 2005 | Comments Off on Large scale topographical mapping for Republic of Maldives

The National Remote Sensing Agency (NRSA), Hyderabad, India has carried out mapping of entire Maldives at 1:25000 and sixteen selected islands at 1:1000 scale for the fi rst time in the history of Maldives

Oct 2005 | Comments Off on International Terrestrial Reference Frame (ITRF)

The International Terrestrial Reference Frame (ITRF) “yy” is a realization of the International Terrestrial Reference System (ITRS), where the “yy” represents the year of the solutions. Since its fi rst realization in 1988, there have been many variations and additions in use of data types and changes in computational strategy.
International Earth …