GPS Accuracy #

The most important function of any GPS device is accuracy. Over the years, PocketFinder has worked diligently with our manufacturing partners to bring reliable and accurate GPS devices to market.

Below is a review of what “Accuracy” means in GPS, how it’s determined, and what PocketFinder’s thresholds are.

THRESHOLDS

GPS — If the location received is determined to be within 50 meters of the device, this is considered accurate and will publish

WiFi & Cell ID — If the location received is determined to be within 75 meters of the device, this considered accurate and will publish

ACCURACY

GPS

GPS signals from satellites constantly rain down on the earth. As they rain down, these signals start bouncing off of buildings and any other physical structures (including bodies of water, cliffs, thick storm clouds, etc.) This bouncing off physical structures causes “interference”. It’s almost like each time the signal hits a physical structure it gets a checkmark to note interference occurred.

So, as your device gets hit with these GPS signals, it sends these signals to the servers and they look for the one with the least amount of “check marks”. Less check marks means less interference and thus better accuracy. But, essentially all GPS signals received have some interference. Likewise, that signal holds the GPS coordinate of the last “physical structure” it bounced off of before hitting your device.

So, this is why, even the most accurate location is still even just a foot off from where the device physically is. The GPS signal bounced off the ground a foot in front of the device before connecting with it.

The server, a learning machine, is able to read the level of interference and determine if this GPS coordinate can be considered within X meters of where the device physically is. If it is considered within range, then that GPS location will be published.

For the PF+ and Smart Tracker, if no good GPS signal is received they can try WiFi. For Wired Vehicle Trackers and the “Teen Driver”, if there is no good GPS, the device will not publish until it gets a valid GPS coordinate.

WiFi

WiFi accuracy is a little more simple. If all the GPS signals the device is receiving are “bad”, it will automatically switch to WiFi Touch and search for WiFi signals.

The device cannot communicate nor connect to WiFi. This is for security purposes regarding your device and privacy. But, nearly every WiFi signal has a public “tag” with its lat/ long coordinates and assigned address. These coordinates and address are assigned by the WiFi service provider.

As your device reads these “tags”, it is also seeing how “strong” this WiFi signal is. The stronger the signal, the closer the device is to the WiFi source; thus, the more accurate the location will be.

If the signal is considered strong enough and within range, the location on that signal’s “tag” will be used as the location of the device.

Cell ID

This location feature is rarely used by the PF+ and Smart Tracker because the locations received are rarely accurate.

In the event your device cannot obtain valid GPS or WiFi locations, it does have one last thing to try.

The device will use local cell towers to triangulate an approximate location. The trouble is, most cell towers are so spread out that the location information received is the equivalent of “somewhere within 2 miles of the cell towers”. This is not accurate enough to post/ ensure the safety of your loved one.

But, in the event you are within 75 meters of a cell tower and GPS and WiFi are not viable, then, triangulation can be accurate enough to publish.