How to Enhance GNSS Performance: the Advantages of Omnidirectional Antennas in Time to First Fix

Manufacturers face major challenges when designing and developing an asset tracker, including concerns such as performance, battery life, and accuracy. The antenna provides the “ears’ of the device playing a critical role in ensuring reliable data transmission for asset monitoring solutions by reliably listening for the satellite signals that determine positioning.

How to overcome modern-day asset tracking challenges
With the need for more compact designs for asset trackers, new solutions are needed. For many years the antenna option chosen for tracking solutions using GNSS (GPS, GLONASS, GALILEO, and BeiDou) has typically been patch antennas. These antennas provide good reception thanks to being Right Hand Circularly Polarized (RHCP), the same as the GNSS signals from the satellite transmitters. However, they must always be positioned facing upwards and flat to efficiently pick up the signals. This was fine in the past, but as we’ve started using trackers in more varied and unpredictable situations, where these patch antennas can run into issues. Think about a tracking device on a parcel that may be stacked upside down or sideways in transport. It’s not always going to be steady or pointing straight up.  The patch antenna’s advantage becomes a liability.

omnidirectional linearly polarized antennas: the 21st-century solution

Recent studies have proved that an omnidirectional, linearly polarized antenna like the Virtual Antenna® solution, provides optimal GNSS performance and signal reception addressing the challenges associated with diverse tracking device requirements as well as providing a small footprint. Virtual Antenna® components, such as the DUO mXTEND™, enable flexible mounting and orientation options ensuring an enhanced satellite reception regardless of the tracker’s orientation and position. An omnidirectional antenna can effectively receive signals from multiple satellites, facilitating a rapid fix, whereas traditional patch antennas require a distinct orientation to operate successfully.

A rapid fix is evaluated through a feature called Time to First Fix (TTFF), which measures the time required for a GPS navigation device to acquire satellite signals and navigation data and calculate a position solution. Fewer seconds means a faster connection. A faster connection means higher accuracy and lower power needed. The result is a more reliable positioning device and a lowered carbon footprint due to longer battery life.

Here you can see Virtual Antenna® solution TTFF in red and patch antennas TTFF in gray.

So, in unpredictable situations, like if a tracking device is moving around or blocked by buildings, the signal strength might drop a bit. But that minor reduction has little impact. What matters the most is how the antenna picks up signals from different directions. By using Virtual Antenna® components it doesn’t matter which way a device is pointing – it can pick up satellite signals no matter its position.

The patch antenna: delayed TTFF

But for the patch antenna, if it’s not pointing up at the sky it’s like trying to listen to a conversation in a noisy room – the signal it picks up isn’t as good or as accurate Or, for example, when the IoT device is on a vertical wall of a cargo container where the patch antenna is not pointing to the sky but to the horizon, the signals are weaker and TTFF is much delayed.

Final thoughts

To sum up, asset tracking has become more complex, and device sizes are becoming smaller in many applications. It is no longer good enough to have a solution that cannot respond easily to the random positions and orientations of tracking devices, linear polarized antenna boosters like the Virtual Antenna® solution ensure a better TTFF than patch antennas, and with better TTFF comes more efficient battery life and accuracy which are table stakes for the category in today’s market.