What is Differential GPS or DGPS?
DGPS or Differential Global Positioning System is a system that is used to enhance and record the differences between the positions that are shown by GPS (Global Positioning System) signals and the real-time positions. DGPS is more accurate than GPS. There is a mild difference between the readings from a GPS and a DGPS. DGPS provides real-time data. DGPS is used to identify the corrections in the positional readings from the GPS. It is also used to increase the accuracy in positioning during land surveys. The DGPS has two receivers namely the Reference Receiver and the Rover Receiver. The pseudo ranges received by the reference receiver as in any GPS are corrected by the actual ranges received by the rover receiver. Unlike GPS, DGPS does not have a global range. It is localized and its range has local coordinates. This property of the DGPS makes it more accurate and expensive as it caters only to the local requirements.
What is GPS?
GPS is the acronym of Global Positioning System. It is also called NAVSTAR GPS. It is the short form of Navigation System with Time and Range Global Positioning System. It is a satellite assisted navigation system. GPS is mainly used for providing the accurate and precise location and position of a particular object on the Earth. GPS is very useful in Marine and Air Navigation. GPS is widely used in new age automobiles especially cars as a navigation guide. GPS belongs to the government of the United States of America.
There are three components in GPS. They are:
- The Space component – comprises the satellites that provide the data and information regarding the positioning required by the user.
- The Control component – consists of the receiving stations that are set up on the Earth.
- The User component – this is nothing but the user who uses the GPS for navigation and positioning purposes.
GPS vs DGPS
The following are the differences between GPS (Global Positioning System) and DGPS (Differential Global Positioning System).
| S.No. | GPS (Global Positioning System)
|
DGPS (Differential Global Positioning System) |
| 1. | GPS is the acronym for Global Positioning System. | DGPS is the acronym for Differential Global Positioning System. |
| 2. | GPS receives data from only one cluster of satellites. | DGPS receives data from two or more clusters of satellites.
|
| 3. | GPS is less expensive than the DGPS. | DGPS is pricier than the GPS.
|
| 4. | The systems that are embedded with the GPS have a global range. | The systems embedded with DGPS have a localized range. |
| 5. | GPS has a single receiver called the Reference Receiver. | DGPS has two receivers, namely Reference Receiver and the Rover Receiver. |
Surveying Equipment with DGPS or a Differential Global Positioning System
DGPS or the Differential Global Positioning System is the latest technology used in land surveying equipment. It is the enhanced version of GPS or Global Positioning System. The surveying equipment with the DGPS enhances the accuracy of any measurement even if it is by a few centimetres.
Advantages of DGPS or a Differential Global Positioning System
There are many advantages to choosing a DGPS as against choosing equipment like a Total Station, etc. Some of them are:
- DGPS or a Differential Global Positioning System can be used in any environment. DGPS can be used in harsh and rough terrains like hilly areas or wet places like marshlands and rainy areas.
- DGPS or a Differential Global Positioning System provides precisely accurate readings. Even millimetres are corrected.
- DGPS or a Differential Global Positioning System is a lot quicker than many other survey equipment like the Total Stations, etc.
Types of DGPS or a Differential Global Positioning System
There are two main types of DGPS or a Differential Global Positioning System in land surveying. These types are defined based on the are surveyed. If the area surveyed is large, then the DGPS is called Wide Area Augmented System or WAAS. If the area surveyed is localized and smaller in size, then it is referred to as Local Area Augmented System or LAAS.
The commonly used type of DGPS in surveying equipment for land surveying and construction in India is the Local Area Augmented System or the LAAS.
Brands That Manufacture DGPS Or A Differential Global Positioning System
There are many international brands that design and manufacture surveying equipment with DGPS or a Differential Global Positioning System. The popular brands are,
• Leica
• Bosch
• Sokkia
• CHCNAV
Uses of DGPS or a Differential Global Positioning System
A DGPS or a Differential Global Positioning System surveying instrument is used in the following fields.
• Construction (Buildings, factories, warehouses, residences, malls, etc.)
• Infrastructure Development (laying of roads, laying of railway lines, airport runway construction, dams, bridges, etc.)
• Mining
• Land Surveying
• Geological Surveying
• Archaeological Surveying
DGPS or a Differential Global Positioning System Models
The popular Models of DGPS or a Differential Global Positioning System Surveying Instruments in India in 2021 are,
• DGPS HI TARGET V-30 by CHCNAV
• DGPS – Leica ICG70T Differential GPS by Leica
• Leica DGPS GS-18T by Leica
• CHC NAV i50 DGPS by CHCNAV
Pointers for choosing the right DGPS
There are a few things to keep in mind before choosing DGPS equipment. They are:
o Warranty
o After Sales Service
o Price
o Reviews from users
o Ease of use
o Accuracy
o Portability
o Simple assembly
o Reliability
o Long Life
o Low Maintenance
