Most surveyors are well-acquainted with the various models and features of GNSS receivers—but have you ever wondered what's hidden inside that compact and rugged housing? Despite differences in shape or manufacturer, most GNSS RTK receivers share a common internal architecture designed to ensure optimal performance in signal tracking, processing, and power management.

In today's blog, let's take a closer look at the internal structure of a GNSS receiver and explore each key component inside.

1. Upper Housing

The upper shell forms the outermost protection for the receiver. Typically built from reinforced plastic, it offers durability against physical impact and environmental conditions. It's also often designed with antenna placement and signal transmission in mind, keeping GNSS signal loss to a minimum.

Functions:

• Provides structural integrity

• Shields internal components from water, dust, and shock

• Allows for GNSS signal transparency when using non-metallic materials

2. GNSS Antenna

At the heart of every receiver is the GNSS antenna, responsible for capturing signals from multiple satellite constellations. Depending on the receiver's application, it may use a geodetic or helical antenna to optimize signal quality and consistency.

Functions:

• Receives GNSS signals (L1/L2/L5, etc.) from satellites

• Supports multi-constellation, multi-frequency tracking

• Crucial for positioning precision and signal stability

3. Shielding Cover/Antenna Bracket

Placed directly under the antenna, the shielding cover is a metal layer that isolates the antenna from potential electromagnetic interference (EMI) caused by internal electronic components.

Functions:

• Reduces signal distortion caused by board-level EMI

• Helps maintain GNSS signal integrity

4. Mainboard (Motherboard)

The mainboard is the receiver's brain. It houses the GNSS engine, processing unit, communication modules (radio, Bluetooth, Wi-Fi, 4G), and IMU module. It executes positioning algorithms, processes correction data, and controls all system operations.

Functions:

• GNSS signal decoding and real-time processing

• Integration with communication and sensor modules

• Power and memory management

5. Battery

Most RTK receivers are equipped with internal rechargeable batteries that provide long-lasting field operation. Battery design focuses on capacity, energy efficiency, and safe thermal performance.

Functions:

• Provides power to all components

• Includes power management circuits for safety and efficiency

6. Front Panel

The front panel is the user's direct interface with the receiver, which is normally on the lower shell. It typically includes status LEDs, function buttons, and sometimes a screen for easy configuration and operation.

Functions:

• Displays working status (power, satellite, radio, Bluetooth, etc.)

• Allows quick start, stop, or mode switching

• Improves usability in the field

7. Lower Housing

The lower shell completes the enclosure and often integrates both the mounting system and external interface connectors. Like the upper housing, it ensures durability and protection, while in some models it also plays a role in heat dissipation. Commonly made of high-strength materials like magnesium or aluminum alloy, it is designed to endure harsh outdoor conditions.

Functions:

• Structural support and protection

• Heat conduction and waterproof sealing

• Interfaces for tripod or pole mounting

• External connectors like SIM card slot, USB port, radio antenna port, and power interface

Although different GNSS receivers may vary in design, features, or branding, their internal architecture remains largely consistent and purpose-driven. From the GNSS antenna at the top to the mainboard and power system inside, each component plays a critical role in delivering stable, centimeter-level positioning in real-world field conditions.

Understanding these components not only helps you choose the right receiver for your work but also gives insight into how positioning technology achieves such impressive accuracy in challenging environments.