Knowledge Base

Where Technology Meets Evolution

Global Navigation Satellite Systems

How It Works

The term GNSS stands for Global Navigation Satellite System(s). A GNSS typically consists of three segments: the satellites orbiting the Earth, stations on the ground to track and monitor the satellites, and users who rely on the satellites to compute their position and motion. There are several independent GNSS in operation today:

Always Growing. Always Expanding.

About GNSS Technology

How It Works

A GNSS receiver recognizes where each satellite is in its orbit and compares it with the time required to receive each satellite’s signal. The receiver uses these measurements to calculate its specific position on Earth.

A GNSS receiver can only track satellites orbiting above the horizon. Typically, there are between 6 to 12 satellites visible above the horizon at any one time. The receiver tries to track all visible satellites. If some satellites become blocked or “shaded” by tall buildings or other major obstacles, the receiver automatically attempts to reacquire the blocked signals. Although a GNSS receiver needs at least four satellites to provide a three-dimensional solution (latitude, longitude, and altitude), it can maintain a (latitude-longitude) position using three satellites.

GNSS constellations are designed to provide worldwide positioning services with an accuracy ranging from 5 to 15 meters. More precise accuracies are not possible with standard GNSS, due to minor timing errors and satellite orbit errors, plus atmospheric conditions that affect the signals and their arrival time on Earth. However, there are ways to improve GNSS accuracy using additional services. There are four primary services available, each capable of improving position accuracies to better than one meter:

Space Weather Status

Conditions, Maps, & Weather Status

Space weather refers to the changing environmental conditions in near-Earth space and the space between the sun and the Earth’s atmosphere. Space weather is influenced by occurrences such as solar flare activity, ionospheric variability, and energetic particle events.

The energy emitted from our sun fluctuates over time. Scientists studying the sun’s activities refer to it as the solar cycle. During times of greater solar activity in the solar cycle, heightened ionospheric activity is observed including periods of scintillation, which can cause GNSS signals to be distorted. This reduces the performance of GNSS receivers. Ionospheric scintillation is most pronounced near the Earth’s magnetic equator, most notably in Brazil.

Below are resources that can be used to track space weather conditions:

Current Scintillation Maps:

Current TEC (Total Electron Content) Maps:

Space Weather Conditions:


Hemisphere GNSS, Randy Noland – Heavy Equipment Guide Interview

Q&A HEG Link


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