US military improves the anti-jamming capability of GPS receivers

Curry Mildred 2022/09/02

　　The United States has developed an improved GPS receiver that can provide 36-40dB. This anti-jamming method is called "anti-jamming autonomous integrity monitoring extrapolation", which is realized by fully coupling the GPS receiver and inertial navigation at the carrier phase level. It is understood that this new type of anti-jamming receiver was originally installed on the outer space-to-surface missile developed by the company.

　　Several methods should be used to improve the anti-jamming capability of GPS satellite systems. The main methods include enhancing the power of GPS signals and avoiding the radiated energy of jammers. The methods of avoiding the radiated energy of GPS jammers include adaptive frequency tracking or beams. forming techniques, as well as beam nulling techniques or post-correlation beams.

　　1) Enhance GPS signal power

　　The United States is making anti-jamming improvements to Lockheed Martin's ILR satellites and Boeing's GPS-ILF satellites. In order to enhance the signal power of the satellites, a new military positioning signal M code has been developed. It is very helpful to improve the use effect of the global positioning system in the confrontation situation. At the same time, since 2003, the United States has increased the signal power of GPS satellites by 10dB. Among the 26 GPS-II satellites planned to be launched, there are at least 20 satellites. higher power satellites. In addition, when the GPS-III project with stronger anti-jamming capability was started, it took 30 years to develop and build the GPS-III group and ground control station. Compared with the current satellites, the anti-jamming capability of GPS-III is 100-150 times higher. Figure 1 is a schematic diagram of the anti-jamming capability of the US GPS system.

　　2) Improve GPS receiver and use an adaptive antenna

　　Improving GPS receivers and using adaptive antennas can increase the anti-jamming capability of GPS by 20-30dB in a short period of time, but large-scale adjustments and improvements require a lot of money, which is difficult for ordinary companies to afford. Therefore, Boeing believes that the number of satellites should be adjusted, and the most effective method at present is to increase the GPS transmission power on the satellites to 500W, which can not only effectively improve the anti-interference ability, but also improve the compatibility of the receiver.

　　All in all, GPS, as a powerful and constantly improving navigation and positioning system, plays a pivotal role in information warfare, but there are also many drawbacks. Only by fully understanding the interference and anti-interference problems of GPS signals can we be in a dominant position in the war.