Remote Sensing

The objectives of the researchers working in the Remote Sensing lab are focused on studying innovative methods and techniques for the processing & interpretation of remotely sensed data in the areas of Disaster management, Agriculture, Polar Cryosphere, Climate Change, GIS & GNSS,  Mapping and Digitization. The most commonly used microwave imaging sensor is the Synthetic Aperture Radar (SAR). SAR is a radar system capable of providing high-resolution microwave images. They have unique characteristics compared to regular optical images acquired in the visible or infrared bands; for this reason, radar and optical data can be complementary, as they carry on a different informative contribution.

Why Do We Research the Cryosphere?

The entire climate system relies heavily on snow and ice. The cryosphere keeps Earth from being too heated by acting as a highly reflecting barrier. Open water or bare land reflect more sunlight than snow and ice. As a result, the presence or absence of snow and ice influences heating and cooling over the Earth’s surface, affecting the planet’s overall energy balance. Air temperatures, sea levels, ocean currents, and storm patterns are all affected by changes in snow and ice cover across the planet.

GNSS – IRNSS / “NavIC” (Navigation with Indian Constellation)

The lab is also engaged in GNSS related research activities namely IRNSS Navigation Receiver Field Trial and Data Collection. IRNSS is India’s own regional navigation system renamed as Navigation with Indian constellation (NAVIC). It is designed to provide accurate position information service to Indian users and the coverage area extends up to 1500 km from the boundary of India, which is its primary service area. The IRNSS System is expected to provide a position accuracy of better than 20 m in the primary service area. IRNSS provides two types of services namely Restricted Service (RS), which is encrypted& available only for authorized users with high precision and Standard Positioning Service (SPS) to all users. Presently there are seven satellites in the constellation placed above 36,000 km from the surface of earth. Three satellites are placed in geostationary orbit at 32.5° East, 83° East, and 131.5° East longitude with fixed position. The other four satellites are in geosynchronous orbit, where each set of satellites will cross the equator at 55° and 111.75° East. The IRNSS satellite signals are available at L5 band (1176.45 MHz) and S band (2492.028 MHz) microwave frequencies.

IRNSS receiver had been installed at CIIRC^®– Jyothy Institute of Technology by SAC-ISRO, Ahmadabad to enhance the receiver position accuracy through field trial and data collection under different environments. The research team is carrying out basic research and experiments with the IRNSS receiver data collected at this lab. The activities include:

1. Performance evaluation of IRNSS user receiver
2. Interference study for IRNSS user receiver
3. Development of marine navigation application for fishermen using IRNSS user receiver
4. Position accuracy analysis using Hadoop
5. IRNSS receiver related android applications

GNSS – DGPS

With the GPS method the position can be determined with an accuracy of several meters. This is usually accurate enough for recreational navigation, but for certain applications higher order accuracy is needed. A method to achieve this is differential mode GPS. The DGPS system involves installing a reference base with known coordinates. This real-time receiver carries out distance measurements between the receiver and each of the visible GNSS satellites. The measured distances include many errors that degrade the positioning accuracy. However, the base, of which we have the actual coordinates as well as those of the satellites, can calculate the theoretical distance without error. The difference between the theoretical distance and that measured for each satellite gives the global measurement error that will be used to correct the station of unknown coordinates of which we seek to determine the position. The correction can be done using post-processing techniques or in real time (GSM or radio link with the base). For real time corrections, we speak of “real time kinematic” GPS or Real Time Kinematic (RTK). It is these local correction systems that we call Local Area Augmentation System (LBAS). Under normal conditions, the accuracy of DGPS measurements is in the order of millimeters. This lab has an higher end DGPS system procured (SP80 model) from Spectra Geospatial Inc.

Unmanned Air Systems (UAS)

This lab is also equipped with wide variety of UAS which includes self designed prototypes and ready to fly systems . These UAS are used for GIS mapping and other educational R & D purposes. The payloads include RGB, thermal , NIR and atmospheric sensors. The UAS are all registered under DGCA with UIN and with licensed piloting.

Some of the most common commercial applications and uses for UAV Drones are:

• Aerial Photography & Videography
• Real estate photography
• Mapping & Surveying
• Asset Inspection
• Payload carrying
• Agriculture
• Bird Control
• Crop spraying
• Crop monitoring
• Multispectral/thermal/NIR cameras
• Live streaming events
• Roof inspections
• Emergency Response
• Search and Rescue
• Marine Rescue
• Disaster zone mapping
• Disaster Relief
• Forenzics
• Mining
• Firefighting
• Monitoring Poachers
• Insurance
• Aviation
• Meterology
• Product Delivery

FIELD VALIDATION

Remote sensing based measurements become complete only when the results are validated with the field datasets. Our team has actively carried out fieldworks related to Glacier, ice  and snow at Himalayas, Karakoram and Arctic region using GNSS/DGPS, Unmanned Air Vehicles, Snow parameter measurement tools, etc. Field work has also been carried out at other locations for various applications and projects.