5 tips to enhance position accuracy in standard precision GNSS receivers

Position accuracy is a key performance metric in many IoT applications, from asset tracking and telematics to consumer wearables and smart mobility. Yet, many developers struggle to reach the level of accuracy they see in GNSS receiver datasheets. This blog outlines practical steps for optimizing positioning performance with u-blox standard precision GNSS (SPG) products and highlights how the SPG 5.30 firmware features introduce new capabilities to standard precision GNSS. 

Understanding the challenge

If you are working on IoT devices for aftermarket telematics, asset tracking, or other applications, you are likely aware of the accuracy gap between theory and reality. While typical GNSS receivers advertise 1–2 meters average position accuracy, users often see 2–5 meters average with occasional outliers reaching 20 meters or more.

What is behind GNSS accuracy issues in IoT?

GNSS receiver performance issues are typically due to system design and configuration rather than the receiver itself. In most scenarios, improved accuracy can be achieved with optimizations while staying within the SPG product family, without the necessity to upgrade to high precision GNSS (HPG) solutions.

Why high-precision mostly isn’t the right choice for IoT

Switching to HPG might seem like the obvious answer. But for many IoT applications, it’s simply not feasible:

• Signal constraints: Many devices have limited sky visibility and use small integrated antennas with signals that are insufficient for HPG receivers.
   
• Power consumption: HPG receivers typically consume 3–5 times more power than SPG solutions, making them unsuitable for small battery-operated devices.
   
• Higher cost: Beyond hardware, HPG often requires subscription-based correction services.  

For developers who need a better balance of power, cost, and accuracy, here is how to get more out of u-blox SPG receivers.

Tips to maximize SPG accuracy 

1. Optimize RF design

Good signal quality starts with good RF design. Here’s what matters:

• Signal level is crucial: Ensure sufficient antenna gain and matching to avoid weak or distorted signals.
   
• Avoid RF interference: Co-located radios (e.g., cellular, Wi-Fi) can degrade GNSS accuracy. Choose modules with integrated RF filters or design your own robust filtering stage.
   
• Prevent LNA saturation: Too strong a signal can be just as harmful as too weak a signal. Avoid overdriving your front-end by adding a filter in front of it.

🔧 Tool tip: Use u-center 2 to monitor RF interference signal levels and AGC (automatic gain control) variance for real-time debugging and optimization of your board design. 

📚 More on this topic: Technical webinar on RF interference

2. Tune receiver configuration

The default settings of your GNSS receiver are good, but not always optimal for your specific application. Here is what you can adjust: 

• Enable more constellations: Adding more constellations like Galileo or BeiDou improves geometry and accuracy 
  📖 Read more: GPS accuracy with four GNSS constellations
   
• Enable SBAS signals: Satellite-Based Augmentation System (SBAS) improves accuracy by mitigating ionospheric errors. However, these signals are more difficult to acquire. Using an A-GNSS service is an alternative way to cope with ionospheric errors.
   
• Enable the weak signal compensation feature: Improve performance under weak signal conditions. 
  📖 Read more: Closing the accuracy gap
   
• Tune input and output filters: Adjust the balance between accuracy and fix availability depending on your priorities. Default u-blox settings typically prioritize availability. Input and output filters are especially useful in reducing the number of outliers, for instance when exiting a tunnel.

3. Leverage AssistNow

u-blox’s AssistNow services provide data to speed up time-to-first-fix (TTFF) and improve accuracy: 

• Predictive Orbits: Great for fast fixes, but slightly less precise than ephemeris from the satellites.  
   
• Live Orbits: Offers the best performance, including ephemeris and auxiliary data for mitigation of ionospheric errors, and consequently, enhanced accuracy. 

🚀 AssistNow services can be tested using u-center 2. No registration for the service is required when using an evaluation kit (EVK).  

📖 Read more: AssistNow 
 

4. Consider a different SPG receiver 

If you are still not reaching your accuracy targets, consider choosing a more advanced SPG model:

• Dual-band (L1/L5): Excellent in urban canyons or environments with multipath interference.
   
• Dead Reckoning (DR): Suitable for vehicles (cars, bikes, e-scooters) only where GNSS signals are not too obstructed.

Explore options: Dual-band GPS & Dead Reckoning 
 

5. Use RTCM corrections

For applications that can support some correction data input, RTCM (code-phase corrections) can increase accuracy to the sub-meter level in good signal conditions.

Summary: Better accuracy is within reach

You don’t need to switch to high-precision GNSS to improve your device’s positioning accuracy. You can significantly narrow the gap between your field results and data sheet specifications by:

• Improving RF design
• Tuning configuration parameters
• Using AssistNow services
• Selecting the right SPG receiver
• Using RTCM corrections

At u-blox, we are committed to helping you get the most out of your GNSS solution. With SPG 5.30 and new features like RTCM support and lifetime access to AssistNow Live Orbits on MAX-M10N and UBX-M10150-KB, we are making it easier than ever to achieve reliable, accurate positioning.  

🛠️ Are you ready to test the latest SPG firmware? Try the EVK-M102 with u-center 2 and see the difference.