Most of us use Global Positioning Systems (GPS) every day without a second thought, whether it’s finding our way with google maps or tracking your Uber. But are you aware of the long journey the GPS signal has to take before it reaches back down to you? Due to this long journey across the virtual vacuum of space as it passes through the Earth's atmosphere; the GPS signal is weak by the time it reaches back down to Earth. This weak signal puts the GPS at risk of being deliberately interfered with and jammed. And this is where Anti-Jamming helped to save the day!
For almost 40 years, Western armed forces have relied upon the GPS’ to guide their position, navigation, and timing; both on and off the battlefield.
GPS jamming is the process of using a frequency-transmitting device to block or interfere with the GPS device once the signal is weak enough to be overpowered. As a result of this interference, the GPS receiver is unable to identify its position.
Created by the government, GPS jammers were designed for military use. A mission's success may depend on being able to conceal the position of a vehicle or aircraft. Once the GPS of the opposition is jammed, the jammer is given privacy, enhanced protection, and a general advantage in high-risk circumstances thanks to the devices.
Going back to the time of the Cold War before GPS existed...the Soviet Union and Western States were engaged in a constant battle for control of Electronic Warfare (EW). Radar jamming was the name of the game throughout the early phases of the war. The Soviet TU-16 Badger and its variants, outfitted with a variety of EW instruments, carried certain high-power jammers designed to interfere with radar systems.
Fast-forward to the closing years of the Cold War, the US began working hard to create the revolutionary GPS. The US Navy began experimenting, using satellite navigation to locate US submarines carrying nuclear weapons. With six satellites orbiting the poles, submarines could detect the change in frequency of a wave in relation to an observer, and determine the submarine's location in minutes. However, this did not meet expectations of the reliable and stable satellite navigation system that the Department of Defense (DoD) sought to guarantee.
Considering prior concepts from Navy experts, the DoD chose to supplement their planned navigation system using satellites. They followed through and launched the first fully functional GPS by 1993.
Unfortunately, early faults were recognised with the GPS. One being that it relied on very low-power satellite transmissions, making it extremely vulnerable to jammers. Given the high relevance of jamming at the time, there were concerns that if an adversary discovered GPS, they might easily render it ineffective in operational areas.
And so Anti-Jam GPS Systems came to the rescue…
When GPS is jammed, the platform will inevitably lose its positioning, navigation, and timing.
In an airborne scenario, if an aircraft loses its position and navigation, the pilot no longer knows where it is and must make a potentially disastrous assumption about its location and route; especially in combat situations. Jammed timing can be detrimental to a mission since it can cause other systems to fail such as inaccurate weapons release or other coordinated actions. Most modern Avionics suites rely on an accurate GNSS feed.
This problem isn’t going away anytime soon. Cases of GPS jamming are actually rising with the increased availability of cheap and easy-to-acquire jammers. Therefore, Anti-Jam is more important as ever before in order to protect you mission.
There are three methods in which Anti-Jam systems can tackle this problem:
When interference is detected, the system creates a 'null' in the direction of the jammer that numbs or ignores the unwanted noise. With several jammers, nulls will be emitted in each direction. The number for available nulls is dictated by the system’s channel count.
Directs an RF pattern (or “beam”) in the direction of a recognised GNSS satellite. It makes interference more difficult because it would require a jammer to be placed in the path of the satellite.
Eliminates any narrowband interference that exceeds a threshold defined by statistics. Signals that surpass the power threshold are eliminated, and the remaining signals are transformed for nulling.
For a number of decades, Chelton has been developing and producing Anti-Jam technology that is combat proven. Our Digital Antenna Control Units (DACU) mitigates narrow-band interference, using an excision process, and broadband interference by creating directed nulls in the antenna pattern, providing significant Anti-Jam protection even in highly dynamic, multi‑jammer environments. Our Anti-Jam has been recognised for its effectiveness in protecting against real-world threats.
Eliminate jamming threats from your platform. Visit our Anti-Jam suite here.