GNSS receivers receive signals from satellites to calculate position, velocity and time. This information is stored locally or sent to a monitoring or tracking station.
Accuracy is improved by receiving more signals from multiple satellites at once. It helps overcome the effects of atmospheric interference.
In addition, a multi-frequency and multi-constellation receiver can improve accuracy even when there are obstacles such as buildings or trees.
Multi-frequency signals
GNSS receivers use multiple channels to track signals from several satellite systems. Each channel is designed to capture a specific signal frequency from a particular satellite system. The receiver then uses these signals to determine the user’s location and timing.
Multi-frequency signals improve accuracy by improving radiofrequency interference robustness, enabling the receiver to switch to another frequency if other signals on a single frequency interfere with the GNSS signals. It also helps ensure the signal does not deteriorate due to radiofrequency radiation from other electronic devices nearby.
GNSS receivers from bench-mark.ca/gnss-receivers/ with multi-frequency capabilities can calculate the distance from each signal, known as a pseudo-range, to a target. The receiver then applies this distance to its known location to calculate its precise position.
GNSS receivers with multi-frequency capacity can also synchronize with other devices and systems. It is especially useful in conjunction with navigation and timing applications.
GNSS receivers with multi-frequency feature a suite of advanced interferometry and monitoring technology that can help reduce radiofrequency interference. It includes advanced radiofrequency detection, adaptive triggering, and high-performance receiver clocks.
In addition, a robust receiver channel is also vital for receiving and processing GNSS signals. It must be able to demodulate the signals, extract the navigation and timing information encoded in them, and track the codes and carrier frequencies used by each GNSS signal.
Precise point positioning
GNSS receivers receive signals broadcast by satellites that can determine a user’s position, time, and direction of travel. These signals are used in various applications, including financial networks, cellular systems, the internet, and synchronizing power grids. Depending on the application, a receiver can use various techniques to improve its accuracy.
Precise point positioning is a technique that removes errors in GNSS measurements to provide centimetre-level accuracy. It uses detailed physical models, corrections, and precise GNSS orbit and clock products that are computed before any measurements are taken.
The accuracy of precise point positioning depends on the number of receiver channels, the signal quality, and the GNSS environment. More channels allow the receiver to track more signals from different satellite systems and frequencies, improving its ability to withstand interference from multiple sources.
Another key aspect of a receiver’s performance is its demodulation and code and carrier tracking capabilities. GNSS receivers demodulate signals to extract navigation and timing information, such as satellite ephemeris data. They then track the codes and carriers of these signals to ensure they are correctly matched to the receiver’s location and time.
As a result, these features allow a GNSS receiver to provide users with highly accurate time by synchronizing their local clock with the atomic clocks on board the GNSS satellites. It is critical to ensure that a user’s device will always be within one hour of its intended arrival time.
Augmentation
Most GNSS receivers can achieve an accuracy of 2-4 meters. GNSS receivers need to receive correction data from ground reference stations to improve this. These corrections are based on satellite position and geometry information.
The receivers also include an augmentation algorithm that detects and characterizes environmental factors affecting the signal reception process. They then use this information to apply a mitigation strategy that helps improve the GNSS performance.
In this way, augmentation can significantly increase the accuracy of GNSS. It can also improve the safety and efficiency of navigation systems.
Moreover, augmentation can help solve challenges like multipath and non-line-of-sight (NLOS) reception. These obstacles are especially problematic in urban environments where a GNSS receiver needs to be able to detect and navigate in challenging conditions.
This paper proposes a novel CAN (context-aware navigation) algorithm that helps detect and mitigate these environmental factors in a GNSS receiver. This algorithm uses fundamental quality indicators of GNSS to determine the operating environment and applies the desired mitigation strategy accordingly.
Multi-constellation
GNSS receivers with multi-constellation access enable better accuracy, increased availability and enhanced resilience in challenging environments. They can receive a high number of signals from multiple GNSS systems, including the modernized GPS (L1) and GLONASS (L2) satellite constellations as well as Galileo (software update required).
Many modernized GNSS systems offer positioning services on multiple frequencies in the L-band. It allows receivers to remove the ionospheric delay, a key source of position errors. In addition, multi-frequency receivers can take advantage of upcoming services, such as anti-spoofing and high-accuracy services, that will be available via GNSS signals.
