GNSS vs. GPS explained: What Shop Owners Need to Know

Modern vehicle systems rely on satellite positioning technology that goes far beyond basic navigation. As advanced driver-assistance systems (ADAS) become standard in newer vehicles, forward-thinking shop owners are discovering profitable opportunities to expand their service offerings.

While GNSS systems are often confused with GPS systems, the two have starkly different capabilities. In this post, we’ll explain the differences between the two, why GNSS matters for ADAS systems, and what it means for shops. 

GNSS vs GPS: What's the difference

The first thing we need to talk about is the difference between GPS systems and GNSS systems. 

GPS stands for “Global Positioning System.” It's the American satellite navigation system developed by the U.S. military, and it was the first fully operational system when it launched in 1995.

GNSS stands for “Global Navigation Satellite System.” It's the comprehensive term that encompasses all global satellite positioning systems worldwide. GPS is just one system under the GNSS umbrella. The distinction matters significantly for precision automotive applications.

Why GNSS matters for ADAS

Modern vehicles use advanced driver-assistance systems (ADAS) to keep drivers safe. These systems need precise positioning data. That's where GNSS comes in.

Standard GPS typically has approximately 5 meter (16 feet) accuracy. If you’ve ever checked out a friend’s location on Google Maps, for example, you might see that they show up at a neighbor’s house even if you know they’re sitting in their living room.

While 16 feet is enough for basic navigation when drivers are trying to find their way to a friend’s house, it’s not enough accuracy for ADAS or autonomous driving features. When a car needs to know exactly which lane it's in, 5 meters isn't good enough.

For ADAS applications, GNSS provides the absolute position of the vehicle. It can tell exactly where a car is on the earth. Other sensors like cameras and radar only provide relative positioning.

GNSS systems around the world

Several countries operate their own satellite navigation systems:

• GPS (United States).
• GLONASS (Russia).
• Galileo (European Union).
• BeiDou (China).
• QZSS (Japan).

The best GNSS systems in today's vehicles can utilize multiple satellite systems, which can  facilitate better performance by reducing errors from signal reflections, improving availability, and boosting accuracy. 

GNSS and ADAS integration

GNSS is the key component for providing precise absolute positioning in ADAS systems. Modern vehicles need to be aware of their context and surroundings, similar to human drivers but even better.

Here's how GNSS supports ADAS functions:

Initialization

GNSS provides the initial global position that helps vehicle control systems start up efficiently. Without accurate starting location data, systems would need to search entire global databases to match what cameras and sensors are seeing—a process that uses excessive time and computing power.

Calibration

GNSS positions help calibrate other sensors to maintain their accuracy. Inertial sensors like accelerometers, gyroscopes, and wheel sensors accumulate biases over time, causing accuracy drift. Regular recalibration using GNSS helps correct these biases.

Cross-checking

GNSS serves as an independent verification system. If the GNSS position disagrees with other sensor data, it signals something might be wrong. This is crucial because GNSS uses entirely different data sources than other sensors.

Challenges for GNSS in vehicles

GNSS isn't perfect, and there are currently several challenges with the existing technology. While there is work in place to reduce how these challenges impact ADAS systems, it’s important to keep them in mind.

These challenges include the following. 

Urban environments

In cities with tall buildings, signals can bounce off structures creating "multipath signals" that take longer to reach receivers. These reflections can reduce system accuracy if not properly filtered out. 

Weather and tree coverage

Trees and heavy weather can weaken satellite signals, though they don’t block them completely. This "signal attenuation" affects the receiver's ability to compute accurate positions. This can cause signal weakening or loss. 

Signal interference

RF noise from vehicle electronics, unauthorized jammers, or signal spoofers can overpower GNSS signals. If this happens, the system may be blocked or struggle to work effectively. 

The future of GNSS for ADAS calibration

The evolution of GNSS technologies and their integration with ADAS is set to revolutionize the automotive industry in several key ways:

Enhanced sensor fusion

Future vehicles will combine GNSS data with inputs from different types of sensors (including LIDAR, radar, and sonar) in increasingly sophisticated ways. This integration will significantly improve positioning accuracy even when GNSS signals are weak or compromised. For calibration shops, this means needing tools that can handle this multi-sensor approach.

AI-powered positioning

Advanced AI and machine learning algorithms will process data from GNSS and a vehicle’s sensors, enabling ADAS systems to make smarter, real-time positioning decisions. Calibration procedures will need to adapt to these more intelligent systems.

Multi-constellation receivers as standard

New vehicles will soon use receivers that access signals from multiple satellite systems simultaneously. This improves positioning accuracy and reliability, especially in challenging environments like urban canyons or densely wooded areas.

High-integrity safety systems

New GNSS solutions with ISO-26262/ASIL-B certification will offer high-performance lane positioning for advanced driver assistance. These systems provide trustworthy and precise location data that's critical for safety.

Urban environment improvements

New GNSS receiver technology addresses more urban and city challenges by filtering out signal reflections from buildings, combating RF interference, and resisting signal spoofing attempts. Major manufacturers like General Motors are already working to extend hands-free driving to more highways and urban environments by improving GNSS accuracy in challenging conditions.

Integration with HD maps

High-precision GNSS combined with detailed HD maps will enable complex maneuvers beyond basic lane-keeping, allowing vehicles to safely navigate interchanges, exits, and merges. 

What this means for calibration shops is clear: GNSS expertise is becoming a non-negotiable requirement. As these technologies become standard in new vehicles, shops without the proper equipment and training will lose business to those who've prepared for the future.

What this means for your calibration shop

As a shop owner or technician adding ADAS calibrations to your services, understanding GNSS is critical. Here's why:

1. Higher accuracy requirements: Vehicle manufacturers demand more precise positioning for ADAS calibrations.
2. Expanded equipment needs: Calibration tools need to account for GNSS data, which may eventually result in new or updated equipment as the systems advance further.
3. Increased complexity: You're no longer just aligning a sensor—you're ensuring a complex, interconnected system works properly.
4. Better business opportunity: Shops with this specialized knowledge can charge premium rates for calibration services.

According to industry standards like ISO 26262-9, combining independent systems to implement redundancy creates safer vehicles and drivers, which is an immediate value add. Using high-accuracy GNSS systems creates a stronger safety case for vehicles, especially in challenging environments where other sensors struggle—like highways across deserts or snow-covered roads.

Confidently offer ADAS calibrations with Revv

Here at Revv, we understand the challenges shop owners face in keeping up with rapidly evolving ADAS technology. Our comprehensive calibration systems account for the complexities of modern GNSS requirements.

Our ADAS calibration solution provides everything you need to capitalize on this growing market opportunity—from equipment to training. We help you understand not just how to perform calibrations, but why they're critical for vehicle safety.

Contact us today to learn how Revv can help your shop offer ADAS calibration services to your customers.