Tracking Everything but Ants: How We’ll Navigate the Future

How often do you get lost because your navigation placed you on a nearby street or showed you facing in the wrong direction? If you’re anything like me, the reliance on phone navigation has frequently led you astray. For all these instances, here’s a ready-made excuse for why you’re late again: our current navigation systems are actually pretty unreliable. 

Our current positioning technology is based on a technology called Global Navigation Satellite Systems (GNSS for short). GNSS determines your position by measuring your distance to different satellites and based on this data it guesses the only location that would render such results. However, it’s the technique of measuring the distance that is really incredible. GNSS sends radio waves to your device from space and measures how long it takes for them to get there. It’s pretty astonishing if you think about it in detail. The change in position from your couch to the grocery store is a drop in a bucket compared to the cosmic distance between the earth and the satellite. Nevertheless, they are able to detect it. 

Considering the tremendous task faced by these satellite systems, it’s easy to forgive them a few meters of inaccuracy. Adding to this error is the obstruction of the signal by clouds and other weather conditions. Moreover, in cities, the signal waves can bounce off of buildings and interfere with themselves. Although there exist band-aid solutions to improve these problems, all these compounded errors render GNSS unreliable.

At this point, you might be wondering what’s all this fuss about. Sure, GNSS has problems, but it works well enough. However, the navigation systems are not only important for getting you to the closest Alepa. GNSS is also a foundation of time synchronization that enables, for example, internet communication. Moreover, many emerging technologies like automated driving or quantum communication rely on accurate time and position. In these cases, reliable navigation can be a matter of life and death. These problems created a strong need for a more accurate positioning system.

The new type of navigation nicknamed terrestrial networked positioning system (TNPS) was developed by scientists at the Delft university of technology in the Netherlands. The determination of position is based on the same concept as in GNSS. However, in the case of TNPS, the signal is sent and received by terrestrial transmitters. 

The measurements of the time difference between the signal sent and received need to be unimaginably accurate. Light travels incredibly fast (exactly at 299,792,458 meters per second). Therefore, 1 nanosecond error in time measurement corresponds to 3 decimeter error in position. 

Delft scientists achieve subnanosecond accuracy by employing an already existing technology known as White Rabbit. White Rabbit is protocol, a way of communication present in Ethernet cables. Yes, the inconspicuous ethernet cable that’s gathering dust in your drawer is able to send time data with subatomic accuracy. Think twice about labeling it as “old.”

Using TNPS, scientists are able to determine the position of a device accurately to 2.5 cm. Although it’s an incredible result, technology doesn’t come without its shortcomings. Its operation requires extensive terrestrial infrastructure. Therefore, it is only suitable for urban environments. Moreover, the more accurate the tracking, the higher the chance of its abuse. Using such advanced technologies is always a trade-off between our comfort and the possibility of infringement upon our privacy. It’s a sensitive balance we all must find for ourselves.

References:

Koelemeij, J.C.J., Dun, H., Diouf, C.E.V., et al. A hybrid optical–wireless network for decimetre-level terrestrial positioning. Nature 611, 473–478 (2022). https://doi.org/10.1038/s41586-022-05315-7