Augmentation is the process of enlarging or adding to something. For Resilient Positioning Navigation and Timing purposes, augmentation is taken as adding an additional source of data -an example of this would be providing a system with more precise and more accurate orbital data for each GNSS satellite than the levels of precision and accuracy provided within their own signal broadcasts.
The degree to which the estimated position, speed, or time of a navigation system matches the true value. High accuracy is critical for reliable PNT services, ensuring that positioning information is precise and trustworthy.
A surveillance technology in which an aircraft determines its position via satellite navigation and periodically broadcasts it, enabling air traffic control and nearby aircraft to receive real-time position information. ADS-B is key for improving airspace safety and efficiency.
A tracking system used on ships and by vessel traffic services for identifying and locating vessels. AIS transmits a ship’s position, speed, and other data to avoid collisions and enhance maritime safety.
A data file broadcast by GPS satellites containing coarse orbit and status information for all satellites in the constellation. The almanac helps GPS receivers locate satellites quickly and improve time-to-first-fix (TTFF) when obtaining a position.
The height of an object or point above a reference level, typically above sea level. In the context of PNT, altitude is an essential component of positioning, especially for aircraft, satellites, and geographic systems. It is commonly measured using altimeters or GNSS systems and is critical for navigation, weather forecasting, and air traffic control.
Bands are usually referred to in the context of "frequency bands" which are a range of frequencies in the electromagnetic spectrum. All Frequencies in the radio bands(3 Hz-3000GHz) have an International Telecommunications Union (ITU) designator assigned to them. Some frequency bands in the radio Spectrum have an additional alphabetical designation (IEEE Standard 521-2002, the Standard Radar Frequency Letter-band Nomenclature) associated with them . GNSS signals for instance are broadcast in a range of frequencies between 1-2 GHz, which has been designated as a Ultra High Frequency (UHF) signal in the L-band. eLORAN on the other hand transmits in the 90-110 kHz band which does not have an alphabetical designation but is in the Low Frequency (LF )Band.
Beidou is a Global Navigation Satellite System(GNSS) constellation owned by the Chinese National Space Agency. It provides full global coverage for PNT data.
Traditionally this refers to a specific frequency used by a PNT system to transmit or receive signals. In GNSS (Global Navigation Satellite Systems), a channel often refers to the capability of a receiver to track signals from a particular satellite, with more channels enabling better performance and accuracy.
Alternative systems or technologies that enhance or back up a traditional or primary PNT service, such as GPS. Complementary PNT solutions help maintain service availability and accuracy when satellite signals are degraded, disrupted, or unavailable.
Groups of satellites working together to provide PNT services. Examples include the GPS constellation (U.S.), Galileo (EU), GLONASS (Russia), and BeiDou (China). Each constellation is designed to provide global or regional coverage for reliable positioning and navigation.
The ability of a PNT service to operate without unexpected interruptions. High continuity ensures the service remains consistently available, even during periods of environmental interference or system maintenance.
A Conformal Radiation Pattern Antenna (also sometimes referred to as a Conformal Reception Pattern Antenna). This is a type of adaptive antenna technology that is used to steer the radiation pattern of the antennas such that nulls in the radiation pattern are created and aligned in the direction of any detected Radio Frequency Interference. Common variants are 4 or 7 channel CRPAs which are used on military platforms such as ships, aircraft and armoured vehicles.
A navigation method that estimates current position based on a known previous position, speed, direction, and time elapsed. Dead reckoning does not rely on external signals, making it useful when GPS or other satellite signals are unavailable, but it can accumulate errors over time without corrections from external references.
An event or condition that degrades, interrupts, or denies PNT services, potentially caused by interference, signal obstructions or system failures. Effective resilience strategies help minimise the impact of disruptions on navigation and timing functions.
A radio navigation technology used in aviation to measure the distance between an aircraft and a ground-based transponder. By calculating the time it takes for a transmitted signal to travel to the ground station and return, DME provides precise distance information for pilots.
A measure of the geometry of satellite positions relative to a receiver, affecting the quality and accuracy of GNSS signals. Lower DOP values indicate better satellite geometry and higher positioning accuracy, while higher DOP values suggest degraded accuracy.
A shift in the frequency of a signal caused by the relative motion between a transmitter (e.g., satellite) and a receiver (e.g., GNSS device). The Doppler effect can be used to estimate the speed and direction of a moving object, aiding in velocity determination for navigation systems.
Enhanced LORAN is a modernised version of the Low Frequency Long Range (LORAN) Navigation system that was developed by the US in World War II. It is a terrestrial based system that uses a low frequency signal (90-110 Khz) to transmit PNT data. The use of low frequency signals means that eLORAN transmissions are capable of carrying data over large distances and can be received inside buildings or even underground and under shallow water.
Precise data broadcast by GNSS satellites, detailing their exact position, velocity, and onboard clock errors. The ephemeris information is crucial for receivers to accurately calculate their own position by understanding the location of each satellite at any given moment. It is updated frequently to maintain precision in positioning.
An imaginary line around the middle of the Earth, equidistant from the North and South Poles, dividing the Earth into the Northern and Southern Hemispheres. The Equator is at 0° latitude and is crucial for geographic coordinate systems. It also plays a key role in defining climate zones and the global navigation reference system.
