SOCET SET Tutorial

SOCET SET is a software application that performs a variety of functions related to photogrammetry. It is developed and published by BAE Systems. SOCET SET is notable because it was the first commercial digital photogrammetry software program. Prior to SOCET SET, all photogrammetry programs were primarily analog or custom systems built for government agencies.

SOCET SET inputs digital aerial photographs, taken in stereo (binocular) fashion, and from those photos it automatically generates a digital elevation model, digital feature (vector data), and orthorectified images (called Orthophotos). The output data is used by customers to create digital maps, and for mission planning and targeting purposes.

The source images can come from film-based cameras, or digital cameras. The cameras can be mounted in an airplane, or on a satellite. A key requirement of the imagery is that there must be 2 or more overlapping images, taken from different vantage points. This "binocular" characteristic is what makes it mathematically possible to extract the 3-dimensional terrain and feature data from the imagery. See Imaging Spectroscopy for more details on stereo image viewing.

A key step, involving very complex least squares mathematics, is Triangulation which determines exactly where the cameras were positioned when the photographs were taken. Photogrammetrists that contributed to SOCET SET's Triangulation include Scott Miller, Bingcai Zhang, John Dolloff, and Fidel Paderas. If the quality of the triangulation is poor, all subsequent data will have correspondingly poor positional accuracy.

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Introduction to Microwave Remote Sensing

Typical radar (RAdio Detection And Ranging) measures the strength and round-trip time of the microwave signals that are emitted by a radar antenna and reflected off a distantsurface or object. The radar antenna alternately transmits and receives pulses at particular microwave wavelengths (in the range 1 cm to 1 m, which corresponds to a frequency range of about 300 MHz to 30 GHz)
and polarizations (waves polarized in a single vertical or horizontal plane).

For an imaging radar system, about 1500 high- power pulses per second are transmitted toward the target or imaging area, with each pulse having a pulse duration (pulse width) of typically 10-50 microseconds (us). The pulse normally covers a smallband of frequencies, centered on the frequency selected for the radar.
Commonly used frequencies and their corresponding wavelengths are specified by a band nomenclature, as follows:

• Ka Band: Frequncy 40,000-26,000 MHz; Wavelength (0.8-1.1 cm)

• K Band: 26,500-18,500 MHz; (1.1-1.7 cm)

• X Band: 12,500-8,000 MHz; (2.4-3.8 cm)

• C Band: 8,000-4,000 MHz; (3.8-7.5 cm)

• L Band: 2,000-1,000 MHz; (15.0-30.0 cm)

• P Band: 1,000- 300 MHz; (30.0-100.0 cm)

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INSAT-4CR

India's Geosynchronous Satellite Launch Vehicle, GSLV-F04, had a successful launch today (September 2, 2007) at 18.20 hours from Satish Dhawan Space Centre SHAR (SDSC SHAR), Sriharikota and it placed India’s INSAT-4CR into the Geosynchronous Transfer Orbit (GTO). The 2,140 kg INSAT-4CR was placed in orbit about seventeen minutes after lift off, about 5,000 km away from Sriharikota.

This was the fifth flight of GSLV and the fourth successful one. NSAT-4CR is now orbiting the Earth in GTO with a perigee (nearest point to Earth) of 168 km and an apogee (farthest point to Earth) of 34,710 km with an orbital inclination of 20.7 deg with respect to the equator.

INSAT-4CR is the third satellite in INSAT-4 series. It carries 12 high-power Ku-band transponders designed to provide Direct-To-home (DTH) television services, Video Picture Transmission (VPT) and Digital Satellite News Gathering (DSNG). It was built to replace an identical satellite, INSAT-4C that was lost due to the failure of GSLV-F02 in July 2006.

INSAT-4CR was developed by ISRO Satellite Centre, Bangalore. The payloads were developed by Space Applications Centre, Ahmedabad. Master Control Facility at Hassan is responsible for all post launch operations of the satellite. The successful launch of GSLV-F04 today has demonstrated the operational reliability of GSLV as well as reiterated the end-to-end capability of ISRO to not only build state-of-the-art communication satellites, but also to launch them using the indigenously designed and built launch vehicle.

Introduction to Remote Sensing

Remote sensing is one of a suite of tools available to land managers that provides up-to-date, detailed information about land condition. Remote sensing uses instruments mounted on satellites or in planes to produce images or 'scenes' of the Earth's surface.

Remotely sensed images can be used in many applications, for example for mineral exploration, monitoring ocean currents, land use planning, and monitoring the condition of forest and agricultural areas. The uniqueness of satellite remote sensing lies in its ability to show large land areas and to detect features at electromagnetic wavelengths which are not visible to the human eye. Data from satellite images can show larger areas than aerial survey data and, as a satellite regularly passes over the same plot of land capturing new data each time, changes in the land use and condition can be routinely monitored.

In the Land Monitor project, satellite images are being used to provide information on land condition and the changes in that condition through time, specifically salinity and the status of remnant vegetation, to help farmers, environmental managers and planners better manage the land. One of the outcomes of the Land Monitor project will be an archive of satellite images of the south-west agricultural region. To get additional information about land condition, the satellite images are combined with other data such as air photos, digital elevation maps (DEMs) and ground data.

Introduction to GIS

Geographic Information System (GIS) is a computer based information system used to digitally represent and analyse the geographic features present on the Earth' surface and the events (non-spatial attributes linked to the geography under study) that taking place on it. The meaning to represent digitally is to convert analog (smooth line) into a digital form.

"Every object present on the Earth can be geo-referenced", is the fundamental key of associating any database to GIS. Here, term 'database' is a collection of information about things and their relationship to each other, and 'geo-referencing' refers to the location of a layer or coverage in space defined by the co-ordinate referencing system.