GPS (Global Positioning System) is regarded as the most widely used technology for determining locations on Earth. But as techniques that make GPS useless grow more sophisticated, moves toward alternative technologies are taking clearer shape.

So-called GPS jamming has become common along the Russia-Ukraine border during the war. More recently, it appears to be spreading in Iran’s Strait of Hormuz.

Often unnoticed, GPS blocking has already become widespread, and its ripple effects are significant.

According to a recent report by The Wall Street Journal, Ami Daniel, CEO of maritime information company Windward, said, “GPS blocking is one of several factors that have made navigation dangerous in the Strait of Hormuz due to war between the United States and Iran.”

In Northern Europe, there have been cases in which aircraft turned back after GPS signals were disrupted near airports. Scenes have also emerged in which GPS blocking reduces the accuracy of advanced weapons.

A hit rate for a satellite-guided weapon deployed by the United States fell to 6 percent from 70 percent after Russia began widespread GPS interference in Ukraine, the WSJ reported. Russia and others are also transmitting fake signals to confuse GPS receivers, it said.

GPS is a technology the United States developed in the early 1970s, when competition between the United States and the Soviet Union over space was intense. It was initially used for military purposes and later opened to civilians. It has the advantages of being cheap and able to locate most devices, but its age means it is not free of various limitations. GPS can be neutralised even by cellphone-sized equipment that costs less than 100 dollars.

That is also linked to why many companies are looking for GPS alternatives. According to the WSJ, work on alternative technologies has long been under way, and some, including inertial navigation systems (INS), are just short of large-scale commercialisation. There are already several startups that specialise in GPS alternatives.

INS has been around for some time, but it is drawing attention as a GPS alternative because it cannot be blocked like GPS and is also accurate. It used to be based on gyroscopes, but today’s technology uses optical fibre, it said. The downside is that it is very expensive. According to the WSJ, good equipment costs millions of dollars. As a result, operators that run multiple ships and aircraft are using INS.

Startups are also emerging to lower the barriers to adopting INS. Anello Photonics is one of them. Anello’s latest product is cube-shaped and consumes very little power, making it usable on drones. Mario Paniccia, Anello Photonics’ CEO, wants to replace large, expensive INS with cheap microchips that can be integrated into smartphones, the WSJ reported.

Some are developing GPS alternatives by detecting the Earth’s magnetic field.

Quantum sensing company SandboxAQ is developing a system that detects anomalies in the Earth’s magnetic field to help ships and aircraft navigate in areas where GPS is blocked. It uses highly precise quantum-based magnetic field sensors to detect the magnetic field, and by comparing patterns of change with pre-built maps, it can provide an alternative to GPS, it said.

Other startups, such as Australia’s Q-CTRL, are developing similar systems, the WSJ reported. This method has the advantage of not being interfered with like GPS, but its accuracy falls short of GPS. Even so, it is assessed as usable enough for ships and aircraft.

Visual navigation, which determines location by comparing what a camera sees with landmarks on maps, has also been around for some time. It has emerged as a technology drawing attention in a post-GPS era. Moves by startups in visual navigation, including Vermeer, are also accelerating.

Alternative technologies are advancing and becoming cheaper, but it is not easy for any single alternative to replace GPS immediately. In terms of universality and accuracy, GPS remains a barrier that alternative technologies find hard to overcome. Even with INS, there is a point that if speed estimates are slightly wrong, location errors can grow over time.

Experts therefore expect GPS alternatives to take the form of multiple technologies that complement each other rather than a single one. GPS alternative technologies will become smaller and cheaper, but to move into civilian fields such as delivery drones, self-driving cars, cruise ships and passenger planes, they will have to undergo extensive testing, the WSJ reported.