# New, More Reliable GPS Hardware Coming Soon

The US Air Force (USAF) has signed a deal to develop a new platform that could solve the problem of unreliable global positioning system (GPS) tracking in densely populated urban areas. It could also help drivers, but through cars rather than mobile devices.

While a sophisticated technology, the principle of how GPS works is remarkably simple. A fleet of satellites orbit the Earth at a consistent speed, meaning their precise location at any particular moment is known.

Each satellite is constantly beaming signals to the ground, with each signal bearing a timestamp. As soon as a device on the ground picks up signals from at least four satellites, it can compare how long each signal took to arrive.

This is enough information to figure out where the device is on the ground to the nearest few feet.

That's the theory at least. While this works fine in open ground, GPS is often less accurate or even unusable in an area with a lot of buildings, making navigation tools less accurate for urban drivers.

## Tall Buildings Confuse GPS Calculations

The problem is that GPS devices assume they are getting signals in a straight line from the satellite. If the signal bounces off another object, the calculations will be slightly out because the signal has taken a longer path than the device realises.

In fact, in some urban areas with a lot of tall buildings, many GPS devices may not even be able to correctly identify which block they are in.

Now, the US Air Force Institute of Technology is teaming up with Australian firm Locata Corporation to develop an improved GPS receiver technology known as 'VRay'. It's a spherical device about the size of a basketball. (Source: insidegnss.com)

## Device Filters Out 'Bounced' Signals

As well as receiving GPS signals, VRay also beams out its own signals in a 360-degree arc. It then checks whether any of these signals come back to the device and, if so, where they land on the sphere.

Using this information, it can figure out the positioning of nearby buildings and other obstacles. In turn, it can then figure out which GPS signals have been diverted and filter them out, instead only using the reliable, direct-line signals.

Though the basic idea of doing this has been around for some time, Locata has only now been able to process the results in real time. (Source: newscientist.com)

It's likely any practical use will be confined to the military -- at least, at first. For example, it may be possible for ground forces to wear a modified helmet that allows them to accurately track their position when fighting in an unknown urban area.

Eventually, however, VRay could be marketed at home and business users. Although the size of the device wouldn't be practical for smartphones or handheld GPS systems, it could be integrated into a vehicle's infrastructure.

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