What is NTRIP?
NTRIP is the transmission of satellite navigation data over the Internet.
NTRIP is the acronym for Networked Transport of RTCM via Internet Protocol, which refers to the transport of a data network in RTCM format via Internet protocol.
In this article we will explain what NTRIP positioning consists of and what are its main advantages when performing RTK surveys with GNSS receivers.
NTRIP consists of the transmission of differential corrections using the standard RTCM format through the HTTP protocol via the Internet. This technique provides a method for sending and receiving GNSS base data over the Internet instead of using UHF radios as is the usual case with RTK.
NTRIP consists of two pieces of software that communicate over the Internet. The server side runs the NTRIP CASTER software. The mobile side runs the NTRIP CLIENT software. The NTRIP sender is responsible for receiving the data stream from the base receiver and retransmitting it over a specified TCP (Transmission Control Protocol) port.
The NTRIP system consists of 04 Components:
NTRIP Source
The generating source of GNSS measurements is considered, i.e. the reference station.
NTRIP Server
It acts as an intermediary in the transmission of data between the source to the Caster.
NTRIP Caster
Transmitting agent, its main function is the dissemination of GNSS corrections to the final devices, likewise, it is responsible for monitoring the quality and integrity of the data.
NTRIP Client
Devices receiving the information flows transmitted by the Caster. End devices are considered personal computers, tablets, mobile phones, GNSS receivers, among others.
NTRIP allows surveying to be carried out more quickly directly from a continuous monitoring station. It can be established from Topographic Control points, to be used as a means of correction for flights of unmanned vehicles.
Advantages
- High absolute precision. With NTRIP corrections, you get high accuracy in your data.
- A local base is not needed. You can work only with a mobile and still perform an accurate survey.
- Quick fix. The Internet connection to NTRIP helps you find the fastest solution.
Disadvantages
- Cost of NTRIP correction service. Some NTRIP networks are private or for special government use, so you must subscribe to a payment to use them.
- Be dependent on the Internet. NTRIP only works over the internet, so you need cellular network coverage to use it. That means, if the topographic terrain is beyond internet coverage, NTRIP is not available. This can be solved using satellite Internet receivers.
NTRIP versus RTK with UHF Radio
It is necessary to mention that NTRIP is a technique within the RTK set, since it allows us to obtain geospatial information in real time. But nowadays, since the techniques of topographic expansion with UHF radios are still being used more frequently, the term RTK is usually assigned only to transmission through UHF radios.
For practical purposes in this blog, the terms RTK-NTRIP and RTK-U HF will be used. Both are real-time capture techniques, but use a different transmission medium.
RTK-UHF uses the Ultra High Frequency band starting from 300 MHz to 3 GHz. The receivers come with an internal radio with power from 1W to 3W, allowing lifting up to 4 kilometers away. But you can also include an external radius to the Base of 12.5W or 25W achieving distances of up to 8 kilometers.
The coverage of the NTRIP service is broad enough
On the other hand, RTK-NTRIP uses the internet as a means of transferring differential corrections in RTCM format, so the coverage is very wide. Sometimes coverage of up to 50 kilometers can be achieved with good accuracy using dual-frequency receivers . Of course, we always need an Internet connection in the work area.
In the United States and Europe there are a large number of Continuous Monitoring Stations transmitting corrections via RTK-NTRIP. So, the end user should only have one Rover Receiver with this system so that it can perform its work. Some networks cost as a monthly subscription, but there are many government stations that are free. In Latin America and Africa, however, services are still scarce.
Our X5 Multiband GNSS Receivers
In this article we wanted to clearly explain what this trend is about, its importance and its implementation with the RTK correction system.
Itis important to mention that our two products: Multi-band GNSS X5 Receiver and the GNSS X5Mobile can be easily used with RTK-NTRIP, and meets all the requirements to carry out demanding projects, providing centimeter position, with multi-band reception and at a total cost accessible.
