Published a blog post on the deterioration of GNSS due to recent solar activities and the effectiveness of SLAM as a countermeasure
Kudan Inc. (headquarters in Shibuya-ku, Tokyo; CEO Daiu Ko, hereinafter “Kudan”), a leading provider of machine perception / SLAM technology in a variety of applications, is pleased to announce that we published our blog post (see attachment below) titled “How to combat GNSS deterioration due to recent solar activities”.
In recent years, increased solar activity and resulting disruptions to social infrastructure have been reported. This blog post explains the impact of this increased solar activity and proposes the need to introduce several approaches that do not rely solely on GNSS as a positioning system as well as the effectiveness of SLAM as a redundancy system, which can act as an integrated security system. mechanism when GNSS signals are not available.
About Kudan Inc.
Kudan (Tokyo Stock Exchange Securities Code: 4425) is a high-tech research and development company specializing in artificial perception (AP) algorithms. In addition to artificial intelligence (AI), AP functions allow machines to develop their autonomy. Currently, Kudan uses its high-level technical innovation to explore business areas based on its own established deep technology stage models that have far-reaching impact on several major industrial fields.
For more information, please visit Kudan’s website at https://www.kudan.io/.
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Name: Kudan Inc.
Securities Code: 4425
Representative: CEO Daiu Ko
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How to deal with GNSS degradation due to recent solar activities
According to the European Union Agency for the Space Program (EUSPA), Global Navigation Satellite System (GNSS) refers to a constellation of satellites providing signals from space that transmit positioning and timing data to GNSS receivers. Electronic devices with appropriate receivers can use this data to determine their precise location on the earth’s surface.
The GNSS system can determine the position of the receiver with an accuracy of approximately several meters. One of the most common enhancements to this technology is RTK-GNSS(Real-time Kinematic), which can increase position accuracy to about 1-4cm.
Some outdoor autonomous vehicles, such as autonomous mining trucks, agricultural robots, mapping solutions, etc., use GNSS, especially RTK-GNSS. When the signal quality is strong, we can detect these vehicles with an accuracy of several centimeters.
The problem: what happened to GNSS?
Although GNSS is capable of accurately positioning autonomous vehicles, we have recently been approached by companies using GNSS and RTK-GNSS for their applications. They have relied on RTK-GNSS to position their vehicles for the past few years. However, recently they have been experiencing continuous disruptions to GNSS signals. When these GNSS signals are not available, the vehicles stop working and they have to wait until
signals recover; costing their business a lot.
Businesses can no longer rely solely on GNSS as a positioning system.
Why does this happen?
The reasoning: why is GNSS unreliable?
GNSS signal disturbances may be related to increased solar activity in the past. In simpler terms, here is the detailed explanation of why this is happening.
Like all other stars, there are regular bursts of vast outbursts of matter, called solar activities. A steady increase in solar activity has been recorded over the past few months and is expected to increase further in the coming years.
According EUSPA, cyclic variations of the solar magnetic field can occur approximately every eleven years. The last solar cycle, 25, began in December 2019 and is expected to peak in impact between 2023 and 2026.
The graph below of the Space Weather Prediction Centerfurther details the solar cycles and predicted timeline:
Figure 2: Progression of the solar cycle
Now that we understand that solar activity peaks every few years, what impact does it have on communication systems such as GNSS?
As we know, the GNSS receiver determines its position through the signals emitted by the satellites orbiting the earth. These signals travel about 20,000 km towards Earth and are mostly unhindered. Distortions and delays in these signals occur due to refraction and
diffraction of signals in the Earth’s atmosphere – particularly in the ionosphere.
According Nasathe ionosphere is where the atmosphere meets space and is home to all of the charged particles in the earth’s atmosphere.
GNSS receivers typically take into account the effect of charged particles on the satellite signal using modeling techniques when the charged particles are evenly distributed. However, increasing solar activities cause fluctuations in the electron density of the ionosphere, distorting the amplitude and phase of GNSS signals.
This phenomenon is called scintillation. Due to irregular distortions, the standard GNSS receiver cannot handle such strong scintillation events. Mild scintillation causes several meters of inaccuracy, and severe scintillation can cause cycle slipsor, worse, complete loss of signal.
This was precisely the scenario faced by the leading mining machine vendor we saw earlier. The location systems we use must be robust to handle the possibility of GNSS degradation, especially since such scenarios are expected to repeat themselves in the future.
So how do you mitigate the impact of solar activities on GNSS?
The solution: can SLAM help?
The first option to overcome GNSS signal disturbances is to look for advanced GNSS systems  which are more robust against the scenarios mentioned above. Systems with advanced receivers can continue to track signals under conditions that challenge standard receivers.
However, if you want to fundamentally counteract it, you need to introduce redundancy into the positioning system. We recommend using 3D SLAM as a redundancy system, which can act as a fail-safe mechanism when GNSS signals are not available .
3D SLAM only requires camera images or 3D-Lidar point clouds to work accurately in an outdoor environment.
For large spaces such as mining sites, agricultural fields and parking lots with large parking spaces, Visual SLAM has an advantage over 3D-Lidar SLAM. 3D-Lidar SLAM requires detecting a significant amount of objects around the sensor, which could not be the case for large spaces as above. Visual SLAM can use visual functions to keep
monitoring in these areas. However, in scenarios with objects in the range of 50m to 100m or during the night, the SLAM 3D-Lidar offers better accuracy and robustness.
The ultimate solution would be to merge a 3D camera and Lidar with GNSS and other sensors. In the long run, this solution would ensure a reliable, robust, and accurate positioning system for your use cases.
If you notice performance issues on your existing GNSS-based positioning system, consider that it might be for the reasons we’ve shared and contact us. We will be able to offer a custom SLAM-based solution to bring back the accuracy and performance your application needs while eliminating any operational downtime due to such disruptions.
Petovello, Mark & O’Driscoll, Cillian & Lachapelle, Gerard & Borio, Daniele & Murtaza,
Hassan. (2008). Architecture and benefits of an advanced GNSS software receiver. Positioning. 1. 66-78. 10.5081/jgps.7.2.156. [PDF]
- Gong, Zheng & Ying, Rendong & Fei, Wen & Qian, Jiuchao & Liu, Peilin. (2019). Tightly coupled integration of GNSS and SLAM vision using 10-DoF optimization on Manifold. IEEE Sensor Log. PP. 1-1. 10.1109/JSEN.2019.2935387. [PDF]
Kudan inc. published this content on August 04, 2022 and is solely responsible for the information contained therein. Distributed by Public, unedited and unmodified, on Aug 04, 2022 03:26:09 UTC.
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