GNSS-SRP is a high-performance, modular GNSS RF front-end designed as a Software-Defined Radio peripheral for advanced GNSS signal processing applications. It enables the real-time reception and transmission of multiple GNSS bands, providing a flexible and powerful platform for both research and professional system development.

The GNSS-SRP is not just a general-purpose SDR. It is a platform specifically engineered to solve the most demanding challenges in GNSS and coherent multi-channel RF systems, while retaining full flexibility for broader SDR applications.

GNSS-SRP FOUR v1.0 block diagram

True Phase-Coherent Architecture (Out-of-the-Box)

Unlike conventional SDR platforms, all RX and TX channels are natively phase-coherent, sharing clocking and synchronization infrastructure. This eliminates the need for complex external synchronization setups and enables immediate deployment.

Integrated High-Power GNSS Front-End

Each receive channel includes:

  • A high-current bias-T (up to 500 mA @ 5 V),
  • A low-noise, high-linearity LNA.

This removes the need for external RF front-end hardware and allows direct connection to:

  • Active GNSS antennas (including multi-band, high-current designs),
  • Passive antennas with optimized noise performance.

Native Multi-Band GNSS Capability

The platform is designed to seamlessly operate with dedicated accessory modules enabling:

  • Simultaneous multi-band reception (L1 / L2 / L5 / E5 / E6),
  • Single-antenna or multi-antenna configurations.

This level of integration significantly reduces system complexity compared to traditional SDR setups requiring external frequency converters.

Scalable to Large Coherent Arrays

The GNSS-SRP supports multi-unit synchronization, allowing expansion up to:

  • 16 fully coherent RX channels,
  • 16 fully coherent TX channels.

A built-in FPGA-based phase alignment procedure ensures deterministic and repeatable calibration across all channels.

High RF Output Power for Real-World Testing

With up to +15 dBm per TX channel, the platform enables:

  • GNSS signal replay and scenario generation,
  • Hardware-in-the-loop validation,
  • Controlled interference and robustness testing.

No external RF amplification is required for most lab and field test scenarios.

Optimized for High-Throughput Data Workflows

Integrated high-speed interfaces allow efficient data handling:

  • SATA (6 Gb/s) for direct high-rate recording and playback using SSDs,
  • 10 GbE via SFP for real-time streaming and distributed processing.

Open and Developer-Oriented Platform

The GNSS-SRP FOUR is built with openness and flexibility as core principles:

  • Compatible with GNSS-SDR, GNU Radio, and MATLAB,
  • Open-source host drivers and open API,
  • Full access to RF control, synchronization, and streaming,
  • Custom FPGA firmware (ROM) support available.

This makes it ideal for:

  • Research and development,
  • Rapid prototyping,
  • Custom waveform and algorithm implementation.

Designed for GNSS — Not Adapted to It

While many SDR platforms can be adapted to GNSS applications, the GNSS-SRP is designed from the ground up for:

  • Multi-band GNSS reception,
  • Multi-antenna coherent processing.

This results in a more compact, integrated, and reliable solution, reducing both development time and system complexity.

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