Precision positioning has never been more critical than it is today. From construction sites to land surveying projects, accurate location data determines the success of operations worth millions.

At the heart of modern positioning technology lies GNSS systems, but achieving the highest accuracy requires more than just satellite signals. This is where radio modems become essential.

A radio modem for GNSS serves as the vital communication link that transforms standard satellite positioning into high-precision surveying equipment. Understanding how these devices work and why they’re necessary can make the difference between centimetre-level accuracy and metre-level approximations.

This guide will explore everything you need to know about radio modems for GNSS.

What Is A Radio Modem?

A radio modem is a wireless communication device that transmits and receives digital data using radio frequency signals. Unlike traditional modems that rely on telephone lines or cable connections, radio modems use electromagnetic waves to transfer information across distances without physical connections.

Radio modems operate by converting digital data into radio signals that can travel through the air. These signals are then received by another radio modem, which converts them back into usable digital information.

Key characteristics of radio modems include:

• Frequency Range: Most operate within specific radio frequency bands, typically UHF (Ultra High Frequency)
• Power Output: Ranges from low-power units for short distances to high-power transmitters for extended coverage
• Data Rate: The speed at which information can be transmitted, measured in bits per second
• Range: Distance over which reliable communication can be maintained

What Is GNSS?

GNSS stands for Global Navigation Satellite System, a broad term encompassing all satellite-based navigation systems that provide positioning, navigation, and timing services globally. While many people are familiar with GPS (Global Positioning System), GNSS encompasses multiple satellite constellations that work together to provide enhanced coverage and accuracy.

The primary GNSS systems include:

• GPS (United States): The most widely known system with 24+ satellites
• GLONASS (Russia): Provides similar coverage to GPS
• Galileo (European Union): Europe’s independent navigation system
• BeiDou (China): China’s growing satellite constellation

GNSS works by measuring the time it takes for signals to travel from satellites to receivers on Earth. By calculating distances to multiple satellites simultaneously, receivers can determine their precise position through a process called trilateration.

Standard GNSS accuracy typically ranges from 3 to 10 metres under normal conditions.

However, various factors can affect this accuracy:

• Atmospheric conditions: Ionospheric and tropospheric delays
• Satellite geometry: The arrangement of visible satellites
• Multipath effects: Signals reflecting off buildings or terrain
• Clock errors: Slight timing differences between satellites and receivers

For surveying, construction, and other precision applications, this standard accuracy is insufficient. Professional applications often require centimetre or even millimetre-level precision, which is where GNSS techniques become necessary.

What Is A Radio Modem For GNSS?

A radio modem for GNSS is a specialised communication device that enables Real-Time Kinematic (RTK) positioning by transmitting correction data between GNSS receivers.
This technology transforms standard GNSS accuracy from metres to centimetres, making it suitable for professional surveying and construction applications.

RTK positioning works by establishing a reference station with a precisely known location. This base station continuously receives GNSS signals and calculates correction data by comparing observed satellite positions with their actual locations.

The radio modem then transmits these corrections to mobile receivers (rovers) in real-time.

The process involves several key steps:

1. Base Station Setup: A GNSS receiver is positioned at a surveyed reference point
2. Correction Calculation: The base station calculates positioning errors in real-time
3. Data Transmission: The radio modem broadcasts correction data to nearby rovers
4. Real-Time Processing: Mobile receivers apply corrections to achieve centimetre accuracy
5. Continuous Operation: The system provides ongoing corrections for moving receivers

Kolida S1 – Best Radio Modem For GNSS

The Kolida S1 stands out as an exceptional radio modem for GNSS applications, offering professional-grade performance at an accessible price point.

This IP67-rated device combines robust construction with advanced features specifically designed for demanding field conditions.

Technical Specifications

The Kolida S1 delivers impressive technical capabilities:

• Power Output: Up to 25 watts of transmission power, providing exceptional range and reliability even in challenging environments.
• Frequency Range: Wide tuning capability from 410 to 470 MHz, allowing compatibility with various regional frequency allocations and avoiding interference.
• Data Transmission: Optimised for high-volume data transfer, supporting all major GNSS constellation signals including GPS, GLONASS, Galileo, and BeiDou.
• Durability: IP67 classification ensures protection against dust ingress and water immersion, making it suitable for harsh outdoor conditions.

Key Features of the Kolida S1

• Wide Frequency Coverage: The 410-470 MHz range offers flexibility for various regional requirements and helps mitigate interference from other radio services.
• High Power Transmission: The 25-watt output power ensures reliable communication over extended distances, typically 10-20 kilometres, depending on terrain.
• Robust Design: Built to withstand challenging field conditions, the S1 maintains performance in extreme temperatures, moisture, and dusty environments.
• User-Friendly Operation: Simplified setup and operation procedures reduce training requirements and minimise the potential for user errors.

Advantages Over Competitors

The Kolida S1 offers several advantages:

• Reliability: Proven performance in diverse field conditions
• Ease of Use: Straightforward operation reduces training requirements
• Compatibility: Works with various GNSS receiver brands and models
• Support: Comprehensive technical support and documentation

Get Your Kolida S1 Today!

Ready to upgrade your GNSS capabilities with centimetre-level precision?

The Kolida S1 radio modem represents an excellent investment in professional-grade positioning technology that will transform your surveying and construction operations.

Afgen, South Africa’s trusted supplier of Kolida equipment, offers comprehensive support for your GNSS needs.

Don’t let positioning accuracy limit your project’s success.

Contact us directly for more information.