Definitions

Follow Avatar Anthony Caplin
Updated : Created :
In this article

Disclaimer: These definitions are intended as a guide and are correct to the best of our knowledge. Should you have any feedback regarding any of the Definitions stated below, please send an email to support@radiodetection.com

NTRIP

NTRIP
NTRIP stands for Networked Transport of RTCM via Internet Protocol. The NTRIP protocol enables the mobile GNSS receiver (RD8200SG) to access data from the RTK base station over the internet to achieve high accuracy. NTRIP can be built in the structure of a mapping app (such as PointMan) or it can be a separate mobile app (such as Lefebure for Android).

NTRIP CASTER
An NTRIP caster is a server that receives data from a GNSS (Global Navigation Satellite System) reference station and broadcasts it over the Internet using the NTRIP (Networked Transport of RTCM via Internet Protocol) protocol.

NTRIP Client
An NTRIP client is a software or hardware device that receives real-time correction (RTC) data from an NTRIP caster. RTC data is used to improve the accuracy of Global Navigation Satellite System (GNSS) receivers.

Mount Type

A mount point refers to a virtual location within a GIS environment where external data can be accessed and integrated. It's like a virtual drive that allows users to access and utilize data from various sources without having to physically copy or import the data into the GIS software.

RTCM
A mount point is a specific data stream that is broadcast by an NTRIP (Networked Transport of RTCM via Internet Protocol) caster. It contains real-time correction (RTC) data that is used to improve the accuracy of GNSS receivers.

MSM (RTCM3.2 and 3.3)
A mount point MSM is a specific data stream that is broadcast by an NTRIP (Networked Transport of RTCM via Internet Protocol) caster. It contains Multi-Satellite Multi-Frequency (MSM) correction data that is used to improve the accuracy of GNSS receivers that are tracking multiple GNSS constellations (GPS, GLONASS, Galileo, BeiDou, etc.).

CMR
A CMR mount point is a specific data stream that is broadcast by an NTRIP (Networked Transport of RTCM via Internet Protocol) caster. CMR stands for Combined Multi-Reference (CMR). It is a type of virtual reference station (VRS) correction data. VRS is a technique that uses data from multiple reference stations to create a virtual reference station that is closer to the rover's location. CMR correction data is typically used for applications that require sub-meter accuracy.

Reference stations

EPSG

EPSG stands for the European Petroleum Survey Group, a non-profit organization that maintains a global reference system for geodetic surveying, including spatial reference systems (SRSs) for geographic locations. EPSG codes are widely used to identify specific SRSs in the mapping and geospatial industry.

RTK
RTK (Real-Time Kinematic) positioning is a method used by an RTK-enabled GPS receiver (called a Rover, in this case the RD8200SG) to obtain extremely precise positions by using data from an RTK base station that is transmitted over the internet (NTRIP).

VRS
VRS stands for Virtual Reference Station, a technique used in Real-Time Kinematic (RTK) GNSS (Global Navigation Satellite System) positioning to improve the accuracy of GNSS receivers. Unlike traditional RTK, which requires a physical reference station within a specific range of the rover, VRS utilizes a network of reference stations and data processing techniques to create a virtual reference station that is closer to the rover's location.

CORS Network
A CORS network, which stands for Continuously Operating Reference Stations, is a network of GNSS (Global Navigation Satellite System) reference stations that provide real-time correction data to GNSS receivers. These reference stations are fixed, ground-based receivers with known locations that continuously collect GNSS data and broadcast it over the internet or other communication channels.
CORS networks are used to improve the accuracy of GNSS receivers by providing correction data that accounts for errors in the GNSS signals, such as atmospheric effects and satellite clock drift. By using CORS correction data, GNSS receivers can achieve centimetre-level accuracy, which is essential for many applications, such as precision agriculture, surveying, and navigation.
CORS networks are typically operated by government agencies or other organizations with a mandate to provide accurate positioning data. The NGS (National Geodetic Survey) in the United States operates the NCN (NOAA CORS Network), which is one of the largest CORS networks in the world.

RINEX
RINEX stands for Receiver Independent Exchange Format, a widely used data interchange format for raw satellite navigation system (GNSS) data. It was developed to facilitate the exchange of GNSS data between different types of receivers and software applications, enabling data analysis and post-processing for various purposes.

Base Station (Reference Station)
A base station, also known as a reference station, is a fixed, ground based GNSS receiver with a known location that continuously collects GNSS data and broadcasts it over the internet or other communication channels. Base stations play a crucial role in improving the accuracy of GNSS receivers, particularly for applications that require centimeter-level precision.

Software

ESRI/ArcGIS
Esri is a global leader in geographic information system (GIS) software, offering a suite of products and services that enable organizations to visualize, analyze, and share geospatial data. ArcGIS is Esri's flagship GIS platform, providing a comprehensive set of tools for mapping, spatial analysis, and data management. It is used by a wide range of organizations, including government agencies, businesses, non-profits, and educational institutions, to solve a variety of problems and make informed decisions.

GIS
GIS stands for Geographic Information System. It is a computer system that allows users to create, manage, analyze, and display geographic data. Geographic data is information about the location and characteristics of physical features on Earth. This data can include maps, satellite imagery, aerial photography, and other types of geospatial data.

CAD
CAD (Computer-Aided Design) software plays a crucial role in creating and editing vector-based maps and spatial data. CAD tools are particularly useful for producing precise and detailed representations of geographic features, such as buildings, roads, and land use boundaries.

Google Earth
Google Earth is a virtual globe, map, and flight simulator program that allows users to explore the Earth from various perspectives. It provides satellite imagery, aerial photography, 3D terrain, and street-level views, enabling users to navigate virtual landscapes and visualize real-world locations.

Data File Type

Shapefiles
A shapefile is a digital vector storage format for storing the location, shape, and attributes of geographic features. It is a widely used format for exchanging geographic information between different software applications and organizations. Shapefiles are typically used to store and manage data for mapping, GIS, and other geospatial applications.

CSV
CSV (Comma Separated Values) files play a crucial role in importing and exporting spatial data. CSV files are a simple and widely supported format that allows for the transfer of tabular data, including spatial coordinates, attribute information, and other relevant details.

Projection File
A projection file, also known as a spatial reference file, is a text file that defines the coordinate system and map projection used for a particular dataset. It provides essential information for correctly representing and analyzing spatial data on maps and in GIS software.

Fix Type

 

DGPS
Differential Global Positioning System (DGPS) is a type of GPS that uses additional information from a network of ground stations to improve the accuracy of position fixes. DGPS can provide accuracy of 0.1-1 meters, which is much better than the 10-15 meters accuracy of standard GPS.

SBAS
SBAS stands for Satellite-Based Augmentation System. It is a system that uses satellites to improve the accuracy of GPS signals. SBAS can provide accuracy of 1-5 meters, which is better than the 10-15 meters accuracy of standard GPS.

GNSS
GNSS stands for Global Navigation Satellite System. It is a collective term for a group of satellite-based navigation systems that provide global positioning, navigation, and timing (PNT) services. GNSS covers all the different satellite systems in use worldwide, such as GPS (USA), GLONASS (Russia), Galileo (Europe), Beidou (China).

GPS

GPS (Global Positioning System): Operated by the United States Air Force, GPS is the most widely used GNSS system in the world. 

Constellations

Constellations are networks of satellites that provide positioning, navigation, and timing (PNT) services to users around the world. These constellations are operated by different countries or organizations and use different technologies to deliver PNT services.

RTK Float

RTK Float also known as Real-Time Kinematic Float, is a positioning mode used in Global Navigation Satellite Systems (GNSS) receivers. It provides centimeter-level accuracy for positioning, navigation, and timing (PNT) applications.

RTK Fix

RTK Fix, also known as Real-Time Kinematic Fix, is the most accurate positioning mode used in Global Navigation Satellite Systems (GNSS) receivers. It provides centimeter-level accuracy for positioning, navigation, and timing (PNT) applications.

L Band Frequency Range

L1 Band

L1 band refers to a specific frequency range used by GNSS satellites to transmit navigation signals. It is the oldest and most widely used GNSS band, operating at a frequency of approximately 1575.42 MHz.

L2 Band

The L2 band refers to a specific frequency range used by GNSS satellites to transmit navigation signals. It operates at a frequency of approximately 1227.6 MHz and is generally used for more precise positioning applications compared to the L1 band.

L5 Band

The L5 band refers to a specific frequency range used by GNSS satellites to transmit navigation signals. It operates at a frequency of approximately 1176.45 MHz and is designed to provide additional robustness and enhanced performance for GNSS applications.

The L5 band carries two primary signals:
In-phase L5 (I5): This signal is designed to improve the accuracy and reliability of GNSS positioning, particularly in challenging environments where signal interference or multipath effects may be present.
Quadrature-phase L5 (Q5): This signal is designed to enhance the integrity of GNSS positioning, providing additional checks for signal quality and reducing the risk of errors.

Mapping the Earth

Ellipsoid
A mapping ellipsoid is a mathematical representation of the Earth's shape that closely resembles its actual form. It is a three-dimensional surface that is slightly flattened at the poles and bulging at the equator, reflecting the Earth's oblate spheroidal shape. Mapping ellipsoids are used as reference surfaces for measuring distances, areas, and positions on the Earth's surface.

Geoid
The geoid is a crucial concept that refers to a specific surface that closely approximates the Earth's true shape. It is an imaginary equipotential surface, meaning that the force of gravity is everywhere perpendicular to it. This surface is extended through the continents as well as oceans, providing a unified reference level for measurements and calculations related to the Earth's shape and topography.
The geoid is not a perfect sphere or ellipsoid, but rather an irregular surface that reflects the Earth's complex gravitational field. It is slightly flattened at the poles and bulges at the equator, a result of the Earth's rotation and the uneven distribution of mass within its interior.

Datum
A datum is a reference system that provides a framework for measuring locations on the Earth's surface. It defines the origin, orientation, and scale of a coordinate system, allowing for consistent and accurate measurements of latitude, longitude, and height.

Geographic Coordinate System

A geographic coordinate system (GCS) is a reference system that defines locations on the Earth's surface using latitude and longitude. It is the oldest and most widely used spatial reference system, providing a global framework for measuring and communicating positions.

WGS84
The World Geodetic System 1984 (WGS84) is the most widely used geographic coordinate system (GCS) in the world. It is a global reference frame that defines the origin, orientation, and scale of latitude and longitude coordinates, providing a consistent framework for measuring and communicating positions on the Earth's surface.

NAD83
The North American Datum of 1983 (NAD83) is a horizontal and geometric control datum for the United States, Canada, Mexico, and Central America. NAD83 was released in 1986 and is based on the 1980 Geodetic Reference System ellipsoid (GRS80). It is the successor to the North American Datum of 1927 (NAD27), which was based on the Clarke Ellipsoid of 1866. NAD83 was developed to improve the accuracy of positioning in North America by considering more recent geodetic observations, including satellite altimetry and Doppler positioning. It is also more consistent with other datums around the world, such as the World Geodetic System 1984 (WGS84).

GIS

Geographic Information System, is a system that creates, manages, analyzes, and displays geographical data. It is a powerful tool that can be used to understand and solve a wide range of problems, from environmental issues to urban planning.

Basemap
A GIS basemap is a foundational layer in a geographic information system (GIS) that provides a background reference for displaying and analyzing other geospatial data. It serves as a visual context for the data, helping users identify locations and relationships between different features.

Feature
A feature is a single entity that represents a real-world object. It is the basic unit of information in a GIS and is typically represented by a point, line, or polygon.

Layer

A layer is a collection of geographically referenced data that is organized according to a common theme or characteristic. It represents a distinct aspect of the real world and provides a way to organize and manage large amounts of spatial data.

Symbology
symbology refers to the visual representation of geographic features on a map. It encompasses the use of various graphical elements, such as shape, color, size, pattern, and transparency, to convey information about the features and their attributes.

Projection
A map projection is a mathematical transformation that converts the curved surface of the Earth onto a flat map. This transformation involves stretching, shrinking, and twisting the Earth's surface to fit it onto a two-dimensional plane.

Map Server
A map server is a software application that provides access and distribution of geospatial data and map services over a network. It acts as a central repository for storing, managing, and delivering spatial information to users, enabling them to view, query, and analyze maps and geographic data.

WFS
The Web Feature Service (WFS) is a standardized protocol for requesting, receiving, and processing geospatial features over the internet. It is part of the Open Geospatial Consortium (OGC) suite of web services specifications, which aim to facilitate the sharing and interoperability of spatial data.

GGA Data fix

GGA Sentence

The GGA sentence, also known as the Global Positioning System Fix Data sentence, is a crucial data message transmitted by GPS receivers. It provides essential information about the position, elevation, and time of a GPS fix.

Static GGA
A static GGA refers to a specific type of GPS fix obtained using a stationary GPS receiver. This fix is characterized by high precision and accuracy due to the absence of movement during the position determination process.

Dynamic GGA
Dynamic GGA refers to a specific type of GPS fix obtained using a moving GPS receiver. This type of fix is characterized by continuous updates of position, elevation, and time information as the receiver navigates through different locations.

(DOP) Dilution of Precision – HDOP, VDOP, PDOP, etc.
Dilution of Precision (DOP) is a crucial concept that quantifies the error propagation caused by the arrangement of satellites used for position determination. It is a mathematical measure that represents the degradation of precision in position estimates due to the geometry of the satellites being tracked.

Other

RTCM
RTCM stands for Radio Technical Commission for Maritime Services. It is a non-profit international standards organization. Although started in 1947 as a U.S. government advisory committee, RTCM is now an independent organization supported by its member organizations from all over the world.

In the United States, the Federal Communications Commission and U.S. Coast Guard use RTCM standards to specify systems such as radar, Emergency Position Indicating Radio Beacons, Electronic Navigation Charts and Maritime Survivor Locator Devices.

Cold Start
The term "cold start" refers to the process of starting a system or device from a completely off or inactive state. It implies that the system has no prior knowledge or data stored in its memory, and it needs to initialize and load all necessary components or software before it can become operational.