Understanding dual-band GNSS

As positioning-based services continue to grow, GNSS technology has come a long way. It’s no longer just about GPS – we now have multiple global systems like GLONASS, BeiDou, Galileo, and regional ones like QZSS and NavIC. Each of these systems sends signals on different frequency bands, and today’s receivers can use these multiple bands for more accurate positioning.

Dual-band GNSS means that a receiver can track signals from satellites on two different frequency bands. A common combination is L1 + L2 or L1 + L5. L1 + L2, which is widely used in surveying and geodesy, while L1 + L5 is becoming a popular choice for industries that require high performance. Thanks to the advanced design of the L5 signal, a dual-band GNSS (L1 + L5) receiver provides more accurate and robust performance compared to a single-band receiver.

Why choose dual-band GNSS?

• Better accuracy
  The L5 signal is designed to be more accurate than L1. In clear environments, a single-band GNSS might give you an accuracy of around 2 to 5 meters, but dual-band GNSS can get that down to as good as one meter.
• Better in multipath environments
  L5 signals are typically less affected by multipath interference, which happens when signals bounce off buildings and other structures. If you’re in an area with lots of signal reflections, like an urban environment, dual-band GNSS will perform better.
• Better at handling atmospheric errors
  By using two signals from different frequencies, dual-band GNSS helps migrate errors caused by factors like ionospheric delays – a major source of GNSS errors.
• Resistance to jamming
  If the L1 signal is jammed, a dual-band GNSS receiver can continue to function using the L5 band. This makes the system more reliable in situations where signal jamming is a concern.

Is dual-band L1 + L5 always the best option for your application?

Not always. While dual-band receivers offer better accuracy and resilience, there are a few things to consider.

1. Antenna requirements
   Dual-band GNSS receivers need an antenna that supports both frequency bands. These antennas tend to be larger and thicker than those used for single-band receivers, so this could be a factor if you have space limitations.
2. Power consumption
   Dual-band GNSS uses two bands (L1 and L5), which means it uses more power. This isn’t an issue for devices with a stable power source, but for battery-powered devices, this extra power usage might be a concern.
3. Cost and effort
   Dual-band GNSS is more expensive, both in terms of the receiver module and the antenna. Plus, designing a dual-band system can be more complex, which can add to the cost.

When should you choose L1 + L5 dual-band GNSS?

• If you need higher accuracy and better performance in challenging environments
• If you want a system that can keep working even if one frequency gets jammed
• If you’re okay with a larger antenna, higher power consumption, and a higher price tag

When should you stick with L1 single-band GNSS?

• If you’re working with smaller devices where space is limited
• If you’re trying to keep costs down (L1 single-band GNSS is much more affordable)
• If power consumption is important (ideal for battery-powered devices like wearables or asset trackers)

How to choose the right GNSS receiver

In the end, it depends on what you need for your specific application. If you need high accuracy or better performance in tough environments, dual-band GNSS is the way to go. But for smaller, more cost-effective devices where battery life matters, a single-band L1 receiver might be the best option.

It’s all about balancing performance, power usage, and cost based on what your application requires.