|
|
Welcome
Welcome to the Survey of India CORS Web Application!
Login
Global Navigation Satellite Systems (GNSS) has revolutionized our ability to access location information. In nutshell it measures its distances from a bunch of satellites hovering over the earth in predefined orbits, through radio signals and estimates its own position on earth. However these system has its own share of error budget due to Orbit errors, Satellite Clock error, Receiver noise, Ionospheric and Tropospheric delays, Satellite Geometry over receiver and multipath etc, which causes dilution in its precision up to 10 -11 meters. To overcome this accuracy limit, various Surveying techniques such as DGNSS, Static GPS/GNSS surveying, RTK, SBAS, GBAS, and PPP are being used by Geospatial community. Each of these method works own principal of taking GNSS measurement. In most of GNSS applications where precise positioning is required, users usually pair their GNSS instruments with other GNSS instruments, simultaneously observing one or more known position, termed as reference station, and with help of these reference stations estimated corrections to be applied over point of interest or rover position are obtained through Static GNSS Survey or Real Time-Kinematic (RTK) Survey methods.
To liberate users from setting of their own reference station each time they wish to undertake GNSS measurement, Survey of India has established a network of Continuously Operating Reference Stations (CORS), which not only capable of providing Real Time Positioning Service through RTK/NRTK with an accuracy of ±3cm, but also host an array of different positioning services targeted to cater requirements for different segments of Geospatial and scientific Community.
At present CORS Network in state of UP and Uttarakhand is operational and The establishment of CORS Network in Haryana, Punjab, Himachal Pradesh, Madhya Pradesh, Rajasthan, Maharashtra and Karnataka is in Progress and will be available shortly. Survey of India is also in process of setting up CORS stations in rest parts of country which will be completed in few months of time.
CORS infrastructure is basically a Network of permanently installed reference stations (or GNSS receivers), continuously streaming raw satellite observations to a central server. The Central sever archive and catalogue these reference station data, analyses and process it for further consumption and host it over web to be used by users. The entire setup of Reference Stations and Central Server is known as Continuous Operating Reference Station (CORS) Network.
The CORS network is available 24 hours per day, 7 days a week and 365 days a year. Its data and corrections are hosted on web in form of open non-proprietary Data streaming standards for easy consumption.
These data/services are available on http://cors.surveyofindia.gov.in
At present following positioning services are being offered
1. Network RTK Services for 3 – 4 centimeter real time positioning.
Real-Time Kinematic (RTK) is a widely accepted technology for accurate positioning and navigation. This method is a extension of Single base RTK survey technique in which, a GNSS rover connecting to a single base or reference station with known coordinates. This survey technique gives centimeter level positioning accuracy. However, by Networking several such reference station range, accuracy as well as reliability of RTK survey technique can be improved multifold. The central server collects all raw observations of these reference stations in real time and runs specialized software, which uses satellite observations of reference stations and performs calculations to create a model of spatially correlated bias and their pattern of change over the whole area. These correction models are made available to users via internet so that GNSS instrument of user can derive bias for its position and refine its position to get centimeter level accuracy in near real time. For utilizing this real time services, user will be required RTK enabled GNSS equipment, a controller unit with RTK field survey software and access to internet via wifi, 4G/5G mobile phone modem or any other mean.
2. D-GNSS Services for 30 – 40 centimeter accurate real time positioning.
GIS users can use DGNSS service to get decimeter level accurate positioning in real time. The standard DGNSS technique consists of the determination of the GNSS position from an accurately-surveyed position known as reference station. These DGNSS corrections improve the accuracy of the Standalone position data by eliminating range satellite range measurements using these differential corrections, and provide a horizontal accuracy of 30 – 40 centimeters. For this real time services, user will be required DGPS/DGNSS enabled GNSS equipment, a controller unit with field survey software and access to internet via wifi, 4G/5G mobile phone modem or any other mean.
3. Online Data processing of static observation with respect of CORS.
At present, for GNSS measurements, users need to pair their GNSS instruments to other GNSS instruments, simultaneously observing one or more Master Stations (Station whose coordinates are known). Duration of observation in these cases increases with respect to distance between Master and Rover stations.
With CORS in place, there is NO need to use paired GNSS equipments. Using single GNSS equipment, control points with respect to National Reference frame can be established with much lesser observation period and better reliability and consistency in Survey work. User can put his GNSS rover, on his point of interest, collect data in static survey mode and upload his data in RINEX format into online processing platform. Online processing platform will process data and provide coordinates of site along with processing report.
4. Downloading of RAW Data of CORS Stations for processing in user software.
For more precise or scientific applications users can download CORS stations raw observations in non proprietary open RINEX format or virtual rinex data (i.e. RINEX files for a virtual reference station that can then be used for post processing calculations), and use it to process his own GNSS data it his own software. These data can also be used to track earth’s crustal movements and other Earth science related studies.
By logging in on this website user can create custom orders; individual stations or multiple stations, epochs, time periods, and various formats such as Rinex2.1, Rinex 2.11, Rinex 3, T02, TGD, DAT, T01 or VRS Rinex and various logging rate 1 minute, 15 seconds, 1Hz, 5Hz, 10Hz, 15Hz, 30Hz...etc.
For accessing all these services users are required to get registered themselves on Survey of India CORS web site, i.e. http://www.cors.surveofindia.gov.in
Application Process:
Users can register by filling the Online Application Form available on the website. For this, users needs to fill the personal information, viz., Name, Address, Mobile Number, Email id, Organization name and also users have to set User name and password.
Along with this, user needs to download hardcopy of application form available in .pdf format on the web site and email its duly filled copy to cors-grb.soi@gov.in along with Scanned copy of ID card issued by Central/State Government office or Academic / Research institute as well as Copy of their personal ID (Aadhar Card/Pan Card).
Within 24 hrs of registration over website as well submission of said documents on email, Users credentials to access CORS services will be activated and intimation of it will be sent to users through email. Please note that for verification of users credentials, users may get call over Mobile Number provided by them.
LIMITATIONS:
Each login entitles the subscriber to access one stream from the CORS servers anywhere in the Network at any time (but not for concurrent streams from two or more devices, to do so requires multiple-login subscriptions).
NO WARRANTIES; LIMITATION OF LIABILITY:
Use of services, applications and features of this website, or any information contained on this website or through any links provided on this website is at the user's sole risk. The Survey of India provides Services on an 'as is' basis. There is no representation or warranty of merchantability or fitness for a particular purpose. CORS Services and information related thereto are subject to change without prior
|
|