What is the difference between a Global Positioning System (GPS) and Visual Positioning System (VPS)

Both a Global Positioning System (GPS) and a Visual Positioning System (VPS) are examples of navigation technology. The former is owned and maintained by the United States Air Force, while the latter is a new technology for Google maps. Both of them operate in different ways for a slightly different approach to computer-assisted navigation.

GPS:

A GPS is enabled by a network of satellites orbiting the Earth at regular, spaced intervals. The original satellites began launching in the late 1970s, under a project called “Navstar.” The project became fully functional in 1995. Russia has a similar system, called Glonass, and the two systems both cover the full globe. Modern GPS systems take both satellite arrays into account for more accurate pinpointing. The full GPS system involves the satellites, ground radar stations, and receivers in a phone or other mobile device.

Explaining how the satellites actually work requires a bit of spacial mathematics. It’s easier to illustrate with an example:

Imagine a boat on the surface of the ocean, with no idea where it is. Now add a fixed green beacon on the ocean surface. If the boat has visual confirmation of the green beacon and knows where the beacon is, it now knows that it’s somewhere in a circular field around the beacon’s location. Now add a way to determine the exact distance from the beacon, for example, measuring 50 kilometers from it. This narrows the possible location to the perimeter of a circle 100 kilometers in diameter centered on the green beacon.

If you add a second beacon, colored red, and likewise the boat can see both, it’s now a question of measuring the distance to the red beacon as well. Once the boat has a distance measurement of both beacons, this narrows it down to just two points, which are where the two circles intersect. To eliminate one of the two points would require a third beacon and a measurement from it as well. There is only one point on a plain which has three fixed lengths relative to three other fixed points.

This is easy enough to understand, but the GPS system has to navigate on the surface of a sphere instead of a flat plane, so it requires a fourth satellite to pinpoint the user to a single point in 3D space. This is exactly the standard by which GPS systems operate, called a trilateration mechanism. To determine distance from the satellite, they use an onboard clock synchronized with time-keeping stations on Earth. Since the speed of light is a constant, a signal sent to a satellite and relayed back to Earth can be measured in microseconds, with the difference between the time intervals being relative to the distance the signal had to travel.

Shortcomings of the GPS standard

Global positioning is fine for the purpose of navigating by sea or air, or on the ground in open country. However, in the cities for general civilian use, GPS systems don’t take into account the presence of roads and obstacles in between. It isn’t as straightforward to navigate across downtown by being told to drive so many miles due straight west.

VPS:

The Visual Positioning System has a completely different method. Instead of satellites, it uses a visual camera image. It then has to compare local streets and find a matching frame of an image to tell where the camera is. Thereafter it can navigate through streets, telling the user to turn left, right, etc. It’s a blend of AI image recognition technology and augmented reality technology, blending symbols on the app screen with the real-life street images.

Google developed the VPS and introduced it at the Google I/O 2018 keynote. The technology would not have been possible without years of Google Maps being established. Google has been sending cars with cameras mounted on top to manually record every street and highway in the accessible world, building a mapped database which integrates with satellite data in Google Maps. Street View is a related technology, in which the user may navigate a virtual avatar along a street found on a map, with captured camera images recreating the experience of being there.

VPS is a logical progression from a globally connected network, exhaustive data, and new cloud storage accessibility. While other companies may eventually implement their own VPS versions and eventually necessitate a standard, so far Google’s VPS is the most fully implemented one.

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