Navigation without satellite Optical gyroscopes as an alternative to GPS positioning

The GPS signal is repeatedly disrupted. A newly developed gyroscope technology is intended to be a precise and interference-free alternative for navigation. It works without satellites and can be used not only on land, but also in shipping.

Satellite-independent navigation is becoming increasingly important as GPS applications are susceptible to interference and spoofing. Spoofing is a deceptive method in which fake GPS signals are sent to mislead navigation systems. In conflict zones such as Ukraine and the Middle East, it has been repeatedly documented how military operations have been compromised by GPS interference. Drones in particular rely on precise positioning - a loss of signal can have fatal consequences.

Optical gyroscopes as an alternative to satellite-based navigation

Since the 1970s, optical gyroscopes such as ring laser gyroscopes have been an established technology for precise rotation rate detection. However, the miniaturization of these sensors posed a major challenge, as signal attenuation and the signal-to-noise ratio became problematic with decreasing size. While microelectronic systems became increasingly compact along the Moore's scale, optical gyroscopes remained bulky and energy-hungry.

In 2018, electrical engineering professor Ali Hajimiri from Caltech achieved a technological breakthrough with the development of an all-optical chip gyroscope that uses Sagnac interferometry. This effect, first described in 1913 by French physicist Georges Sagnac, is based on the fact that two light beams traveling in opposite directions have a difference in transit time when the system rotates. The method is immune to electromagnetic interference, vibrations and cyber attacks - ideal properties for applications in GPS-disturbed or forbidden areas.

Highly integrated gyroscope systems

Building on these developments, two companies - Anello Photonics from California and One Silicon Chip Photonics (OSCP) from Montreal - have launched highly integrated gyroscope systems onto the market. Anello relies on low-loss silicon nitride waveguides that keep the light in the resonator for longer, thereby increasing the signal amplitude and reducing measurement errors. In addition, effective noise suppression ensures that precise rotation rate measurements are possible even with smaller waveguides.

Mario Paniccia, CEO of Anello Photonics, presented an inertial measurement unit (IMU) consisting of three chip-based gyroscopes and other sensors at CES 2024. The system is compact enough to fit in the palm of a hand and delivers high precision, for example in agriculture. Autonomous tractors can use it to make precisely straight furrows up to 800 meters long. According to Paniccia, the position error is only 0.1 percent of the distance covered - i.e. 100 meters per 100 kilometers of driving.

At CES 2025, OSCP presented an advanced IMU that is only half the size of its predecessor and consumes less energy. OSCP founder Kazem Zandi emphasized that these gyroscopes enable dead reckoning with centimeter accuracy.

Combination with GPS and maritime applications

The IMUs from Anello and OSCP are designed for hybrid operation with GPS. If the system detects a GPS disturbance, an AI-controlled switchover takes over navigation using the gyroscopes alone. Paniccia explains: "If you are in New York and the gyroscopes register a 100-meter movement while the GPS suddenly indicates Texas, the system decides autonomously to trust the inertial measurement."

Such systems are particularly relevant for unmanned maritime vehicles. On the high seas, there is a lack of prominent landmarks and currents make navigation difficult. While land-based IMUs achieve an accuracy of 0.1 percent, the error rate at sea is typically 3 to 4 percent of the distance traveled.

Future prospects: Gyroscopes in handheld devices

CEO Paniccia sees further applications in wearable devices. Firefighters could use them to find their way around smoke-filled buildings, even when stairwells and emergency exits are no longer visible. These portable systems would essentially be an electronic version of a magnetic compass - but with far greater precision and independence from external signals. (heh)

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