Techniques for blocking the Beidou GPS signal

To meet the demands of the Internet of Things, the necessity for location services is expanding. Forecasts from several organizations suggest that a considerable 60% of IoT devices will make use of geographical location data. Specifically, the market for extensive outdoor positioning is expected to be highly significant.

Within the realm of navigation systems, there exists a prestigious and highly sought-after club known as the Global Navigation Satellite System (GNSS). This exclusive club, comprising only four members, has managed to capture the interest of heads of state and has become a focal point of research for numerous esteemed scientists and engineers. The esteemed members of this club include the American GPS, European GPS (Galileo GALILEO), Russia's GLONASS, and China's Beidou COMPASS.

China's Beidou system has emerged as a prominent newcomer, boasting the most impressive growth trajectory among its counterparts. What is the current status of Beidou? How does it shape our lives? Undoubtedly, this topic is of great interest. While academic journals offer numerous articles on Beidou, the excessive use of technical jargon renders them unappealing to the average reader.

Block GPS signal

With the ongoing expansion of the GPS locator market, a subset of individuals is now seeking ways to counter GPS signal tracking. To address this demand, the market has witnessed the emergence of GPS signal jammers, which can effectively block the tracking of GPS signals.

The GPS jammer possesses the ability to effectively hinder the GPS locator. When a gps jammer is employed, it disrupts the regular operation of the GPS locator, resulting in incomplete transmission of data to the locator monitoring platform. Just like a mobile phone, the GPS locator requires insertion of a mobile phone card or IoT card to transmit data. Thus, as long as the GPS signal jammer can block the signal transmission of the mobile phone card, it can successfully block the GPS locator.

By releasing radio interference waves, the anti-location jammer disrupts the GPS locator operating within a specified electromagnetic band. This generates an electromagnetic environment akin to the signal-blocking device, effectively blocking GPS satellite signals. Consequently, data transmission to the platform is impeded, rendering the device offline and unable to function properly.This device effectively blocks positioning signals, including GPS, Beidou, and base stations, ensuring reliable shielding. It operates at a transmission power of 5W and offers an adjustable effective shielding distance of 1 to 15 meters (pre-configured during production). By completely blocking the GPS locator within the vehicle space, it guarantees non-functionality without posing any risks to human health.

Start with GPS

The world witnessed the dawn of the space century for humanity on October 4, 1957, when the Soviet Union successfully launched the first-ever artificial earth satellite. This event garnered significant attention from the United States. Within Hopkins's Applied Physics Laboratory, mathematician Bill Guy and physicist George Weifenbach made a remarkable discovery. They observed a phenomenon indicating a shift in the frequency of this satellite, which was later identified as the Doppler shift effect caused by relative motion.

In determining the ideal orbit for the satellite, three possibilities exist: low, medium, or high. Opting for a low orbit would result in decreased launch costs and heightened accuracy. However, it is important to note that achieving global coverage would require the utilization of 200 satellites.

The possibility of global coverage exists if three satellites are positioned in a high orbit. However, the launch of high-orbit satellites is not only challenging but also results in significantly reduced positioning accuracy. This can be attributed to two primary factors: the excessive altitude of the orbit, leading to substantial errors, and the minimal relative speed between the geostationary orbit and ground objects, which hinders the effective utilization of the Doppler frequency shift solution method.

The medium orbit offers a satisfactory compromise, with a minimal requirement of 24-36 satellites for global coverage. The substantial relative speed between the satellite and stationary ground objects allows for the efficient utilization of the Doppler frequency shift method.

Based on the thorough considerations provided above, the United States made the decision to implement a medium-orbit constellation comprising of 24 satellites. The initial satellite was successfully launched in 1978, and the entire system was put into operation in 1995. Presently, there are 30 satellites, categorized into two positioning modes: military and civilian. This approach remains accessible to the global community.

Beidou generation criticized

After the loss of MH370, a lot of popular science appeared, making the public familiar with the term Doppler effect. Is the Doppler effect a good thing or a bad thing for satellites? It depends on what kind of satellite it is. This is a good thing for navigation and positioning satellites, because the greater the relative speed of the satellite relative to the measured object on the ground, the more obvious the Doppler effect, and the positioning will be more accurate. This is even the core principle basis for positioning navigation satellites.

However, the Doppler effect is a bad thing for communication satellites, because the frequency offset will cause communication failure and must be corrected. For example, the Asia-Pacific International Communications Satellite located over the Indian Ocean is fixed relative to the ground. The seven search signals sent by the missing MH370 in the final stage were measured by this satellite and found a frequency offset. This was originally data that was to be corrected, but it was not Thinking of this, it became the only evidence to speculate on the aircraft's trajectory. To sum it up in one sentence: Using communication satellites to position satellites has turned the Doppler effect, which was originally a bad thing, into a good thing.

The scale of Beidou II is similar to that of GPS, and the applied orbit and frequency are relatively consistent with those of European Galileo. This inevitably encounters the problem of competition for satellite orbits and frequencies. Satellite orbits and space frequencies are resources shared by mankind, so how should they be distributed? International rules do not divide them by country or population, but whoever takes advantage first will get it.

In 2005, the first satellite of the Galileo project was launched, but it was not activated. It only occupied the orbit but not the frequency. Why was it not activated? The reason was that there was no money, and activation required money, and Europe was a little tight on money. The first star of China's Beidou II generation also went up to the sky, and it was opened as soon as it went up. Now the orbit and frequency are occupied.

Galileo in Europe was tinkering slowly, while Beidou in China kept launching satellites one after another, and later even built a double satellite. Some frequencies of the Galileo project and Beidou II overlap, and both sides are in the field of international telecommunications. The alliance has been registered, and whoever gets it first will get it. China's fast pace has made Europe anxious, and it has put pressure on China through the United States, asking China to slow down and wait for the European people.