The difference between Beidou and Tiantong satellites

There are satellite differences, functional differences, information differences, etc.

1. Satellite differences

Beidou’s satellites include 5 geosynchronous orbit satellites and 50 22,000 km medium-orbit satellites, covering the world.

2. Functional differences

Beidou is a positioning satellite, and its benchmark is GPS, Galileo and GLONASS. It is used for positioning and is mainly used in the Internet of Things, location reporting, and short message information. Tiantong-1 is a communication satellite, and its benchmark is maritime satellites, Eurostar and Iridium. It is used for making phone calls, sending text messages, and surfing the Internet. In particular, the call function is closer to the daily communication needs of mass users.

3. Message differences

The capacity of a single Beidou message is 120 Chinese characters, and the sending time limit is 1 minute (limited), 5 minutes, and 10 minutes respectively. The maximum number of Tiantong is 70 Chinese characters, and the fastest transmission time limit can be once per second.

Although the purposes of Tiantong-1 and Beidou satellites are completely different, they are both important weapons of the country. Through the continuous research, testing and development of the new and old generations of scientists, they have solved the "stuck" problem of mobile communication satellite technology. "neck" problem, communication services are provided by China, getting rid of dependence on foreign satellite mobile services, highlighting China's international status in the world.

Features of Beidou satellites:

1. Tri-frequency signals

Beidou uses tri-frequency signals, while GPS uses dual-frequency signals. Late mover advantage. Although GPS launched its first tri-band satellite on May 28, 2010, it will still take several years until all GPS satellites are aged and scrapped and replaced with tri-band satellites. These few years have been the dominant period of Beidou. The tri-frequency signal can better eliminate the impact of high-order ionospheric delay and improve positioning reliability.

Enhance data preprocessing capabilities and greatly improve the efficiency of fuzziness fixation. And if there is a problem with one frequency signal, traditional methods can be used to use the other two frequencies for positioning, which improves positioning reliability and anti-interference capabilities. Beidou is the world's first satellite navigation system to provide tri-frequency signal services.

2. Active positioning and passive positioning

Active positioning means that the receiver itself needs to transmit information and communicate with satellites, but passive positioning does not. Beidou's first-generation active positioning technology requires only two satellites to complete positioning, but it requires the support and participation of the information center's DEM (Digital Elevation Model) database in the calculation.

It is retained on Beidou II, but is not used as the main positioning method. The second generation of Beidou uses passive positioning, which is the same as GPS. It does not require the information center to participate in the calculation, and active positioning serves as a supplementary function.

Reference for the above content: Baidu Encyclopedia—Beidou Satellite Navigation System