The Basics

All GPS tracking, whether offered through your smartphone, or a tablet, or our rugged Eagle 1 device, relies on the same satellite networks, operated for most GPS tracking in the U.S. by the U.S. government. GPS tracking requires several systems to work together to produce accurate location information.

There are several reasons that satellites in the sky might not be providing the best accuracy at any given time. 

While most of these issues are outside the control of Momentum IoT, there are features we are deploying to greatly improve accuracy, and solve for “blind spots” when we find them. Read on to see how Momentum is Tackling GPS Drops.

 

Satellites

 

Not Enough Satellites

GPS devices all use a number of satellites in orbit above Earth in order to make a determination on your estimated location.

A minimum of four (4) satellites are required to be in-line-of-sight in order to give the roughest estimation of location. Any number of satellites less than four will return an error message ‘GPS Coordinates Not Available’. The more satellites that can be seen and used to provide readings, the more triangulation points & references are obtained.

Our Eagle 1 device is capable of accuracy down to 2 meters. Of course, this depends on the satellite data it receives, and the strength of each signal.

GPS devices typically need to receive signals from at least 7 or 8 satellites to generate the most accurate locations. With fewer satellites contributing, the amount of uncertainty and inaccuracy increases.

Satellite position is also important. Generally, a set of satellites that are dispersed across a larger area of the sky will return a much more accurate and precise location.

 

Location and Device

 

GPS drift 

The GPS track deviates from the road. You may see that the route generally follows the shape of the road but with much less precision.

This can be caused by reflections and shadowing on an image.

 

Lost GPS signal 

If the GPS signal is lost and sometime later re-acquired the pre- and post-signal-loss points will be treated just like any other two points (although more time has elapsed between them) and connect them with a straight line.

 

Multipath Error

A ‘jumpy’ GPS track can cause your activity to report more distance than you actually traveled since each ‘zig’ and ‘zag’ of your GPS track has to be accounted for with a straight line connecting them.

This specific issue can be caused by having local obstructions that cause the GPS signal to bounce off of, which sends varying location details to your device. This can result in instability of your location.

 

Signal Obstruction

Buildings, trees, tunnels, mountains, clothing, and the human body can prevent GPS signals from the satellites reaching the receiver. In particular, parking in a multi-level garage or in a warehouse will cause signal obstruction.

Most of our Eagle 1 devices are mounted under dashboards or even under the hood in many vehicles. We are able to handle this with a strong built-in antenna. 

Ideally, the device should not rattle too much, as there is also an accelerometer in the device. Rattling can result in false signals.

Obviously, our device should NEVER be installed inside a fully-enclosed metal box. This can act as a Faraday Cage, which is an enclosure specifically designed to block electromagnetic signals.

 

How Momentum Tackles GPS Drops

 

A-GPS 

GPS uses the network of satellites to get your location, while A-GPS (Assisted GPS) uses the network of satellites along with information from the cell towers of your mobile operator to pinpoint your location. This added dimension makes A-GPS faster and more accurate. We use A-GPS.

 

Better Antennas

Our Eagle 1 device’s antenna has improved over time, to both reduce internal interference, and improve strength. Our antennas are soldered onto the device, rather than being glued as some GPS vendors do. This adds a bit of cost to our product, which is proudly Made in the U.S.A. But it also improves signal quality.

 

Better Network

Momentum was the first GPS Telematics provider to offer coverage throughout North America (including Mexico, Canada, and the United States) on the new LTE 4G Category-M network. This network was set aside specifically for machine communications. Because of the set-aside, the 4G network typically has a higher capacity in cities and high usage areas. Also, 4G networks utilize frequency bands below 6GHz. This longer signal wavelength enables a higher range of coverage. For more on this, go here.

 

Device Caching

Our Eagle 1 device has memory chips onboard. We are able to store a cache of GPS pings on-device, and in case the cellular backhaul drops intermittently, we can reconstruct a trip when cellular is restored by sending a compressed packet with all the info. This feature is undergoing continual development to improve accuracy.