DGPS - (Differential Global Positioning System) - It is an modified/ advanced version of GPS that provides an accurate position of an user.

DGPS SURVEY INTRODUCTION:

• The advanced version or the enhancement to Global Positioning System or GPS is DGPS System i.e. Differential Global Positioning System.

• It was developed to meet the needs of Positioning and Distance Measuring. It provides better and improved accuracy than GPS.

• The underlying premise of DGPS requires that a 2 DGPS receiver unit Operated Sequentially, One is Stationary called - Base Unit , and Other is Moving Called - Rover Unit.

• A GPS receiver must acquire signals from at least 4 satellites to reliably calculate a three dimensional position.

• The receiver performs mathematical calculations to establish the distance from a satellite, which in turn used to determine its position.

• This position is displayed on the data logger and saved along with any other  descriptive information entered in field software.

CONCEPT OF DGPS:

1. The DGPS equipment work on GPS/GNSS satellite signal to find out exact position where they are on the Global Scale.

2.The GPS Constellation consist of 24 satellites that orbit the earth in very precise orbits twice a day.

3. GPS satellites emit Continuous Navigation Signals . Each GPS satellite transmits data that indicates its location and the current time.

4. GPS Satellites are in orbits such that one can be able to receive signals from at least 4 satellites to enable for the determination of  Latitude, Longitude, Altitude and Time.

5. Latitude and Longitude are Spherical Coordinates on the surface of the earth.

6.  Latitude is measured in North south of the Equator. Longitude is measured in East or west of Greenwich .

7.. DGPS uses Latitudes and Longitudes to reference Location.

8. DGPS is a system in which differences between observed and computed coordinates ranges at a particular known points are transmitted to users to upgrade the accuracy.

9. Differential Correct is a technique that greatly increases the accuracy of the collected DGPS Data. It involves using a receiver at a known location - "The base Station" and the comparing data with DGPS positions Collected from unknown locations with "Roving Receivers".

  

DGPS SURVEY:

DGPS Survey are of 2  Types:

•  Static

• Kinematic- RTK (Real Time Kinematic) and (Post Process Kinematics).

DGPS SURVEY PROCEDURE:

  To know further about the procedure click on the given link   DGPS SURVEY PROCEDURE     

SPECIFICATION OF DGPS EQUIPMENT.                                      

 We deployed a high performance  GNSS board 600 channels and capable of supporting multiple satellite constellations devices to carry out the DGPS Survey. The technical Specification is given below 

Stonex:

S900A: