The GNSS-SRP FOUR is a high-performance, multi-channel Software-Defined Radio (SDR) platform designed for advanced GNSS signal processing as well as general-purpose SDR prototyping.

It enables applications such as:

  • Multi-antenna GNSS reception,
  • Scientific applications,
  • Advanced receiver implementations,
  • Signal capture.

The system integrates four fully coherent RF transceivers for both reception and transmission, enabling precise phase-aligned operation across all channels. This architecture makes it particularly suitable for multi-antenna systems, spatial processing, and coherent multi-channel experimentation.

GNSS-SRP FOUR v1.0 standalone diagram

Based on the AD9361 RF front-end, the platform covers:

  • Frequency range: 70 MHz to 6 GHz,
  • Channel bandwidth: 200 kHz to 56 MHz,
  • Baseband sampling: 12-bit resolution, up to 61.44 MSPS.

Each receive channel includes:

  • Integrated bias-T (up to 500 mA @ 5 V),
  • Low-noise, high-linearity LNA:
    • Gain: 20 dB,
    • Noise Figure: 0.5 dB,
    • P1dB: 0 dBm.
  • Electronically switchable LNA bypass.

This allows operation with both active and passive GNSS antennas.

On the transmit side, each channel incorporates a switchable RF power amplifier providing up to +15 dBm output power, enabling applications such as hardware-in-the-loop testing and RF scenario generation.

The system is clocked by an onboard ultra-stable OCXO:

  • Stability: ±20 ppb,
  • Phase noise: -117 dBc/Hz @ 10 Hz offset.

This ensures excellent coherence and phase stability across all channels and between multiple units.

At the digital processing level, the platform is powered by an AMD/Xilinx Kintex-7 FPGA (XC7K70T or XC7K160T) paired with 512 MB DDR3 memory.

The platform integrates high-speed connectivity:

  • USB 3.0,
  • SFP (1G / 10G Ethernet),
  • SATA interfaces.

The system is powered from an external 12–24 V DC supply, enabling both lab and field deployment.

The platform is designed as an open and extensible SDR system, supporting widely used frameworks and enabling custom waveform development and FPGA-based processing.

Key Features

RF and Signal Chain

  • 4 × fully coherent RX channels,
  • 4 × fully coherent TX channels,
  • Frequency range: 70 MHz to 6 GHz,
  • Channel bandwidth: 200 kHz to 56 MHz,
  • Baseband sampling: 12-bit resolution, up to 61.44 MSPS,
  • Phase-coherent architecture (shared LO and clocking).

Receiver Front-End

  • Integrated high-current bias-T per RX channel:
    • Up to 500 mA @ 5 V,
    • Hardware-enabled/disabled via microswitch.
  • Low-noise, high-linearity LNA per channel:
    • Gain: 20 dB,
    • Noise Figure: 0.5 dB,
    • P1dB: 0 dBm.
  • Electronically switchable LNA bypass.

Compatible with:

  • Active GNSS antennas,
  • Passive GNSS antennas

Transmitter Chain

  • 4 independent TX channels,
  • Integrated switchable RF booster amplifier per channel:
    • Gain: 15 dB,
    • Output P1dB: +17.5 dBm,
    • Noise Figure: 2.3 dB.
  • Maximum output power: up to +15 dBm.

Suitable for:

  • Hardware-in-the-loop simulation,
  • General-purpose RF signal generation.

Clocking and Synchronization

  • On-board high-stability OCXO:
    • Stability: ±20 ppb,
    • Phase noise: -117 dBc/Hz @ 10 Hz offset.
  • 1 × Reference input,
  • 3 × Reference outputs,
  • 1 PPS input and 1 PPS output.

Designed for multi-unit synchronization.

Scalability

  • Master–slave architecture supported,
  • Up to 3 slave units per master,
  • Up to 16 RX + 16 TX fully coherent channels,
  • FPGA-based phase alignment.

Digital Processing and Interfaces

FPGA

  • AMD/Xilinx Kintex-7 XC7K70T-2FBG484I,
  • Optional: XC7K160T-2FBG484I.

Memory

  • 512 MB DDR3.

High-speed interfaces

  • 2 × SATA 6 Gb/s:
    • Master port compatible with SSDs.
  • 1 × SFP cage:
    • Supports 1 GbE / 10 GbE,
    • Compatible with DAC.
  • USB 3.0:
    • High-speed host connection.
    • Suitable for standalone operation.

Development interfaces

  • JTAG (FPGA programming/debug),
  • UART (low-level diagnostics)

Software and Development Ecosystem

Compatible with:

Features:

  • Open-source host drivers (WaveMasters),
  • Open API for RF and synchronization control.

Supports:

  • Real-time streaming,
  • Custom processing pipelines,
  • Rapid prototyping.

Custom FPGA firmware (ROM) support:

  • Application-specific acceleration,
  • Proprietary processing,
  • Custom IP core integration.

Expandability

Compatible with:

Enables:

  • Multi-band GNSS reception,
  • Multi-frequency single-antenna setups,
  • Multi-antenna spatial processing.

Availability and Ordering

The GNSS-SRP FOUR is currently available for pre-order and reservation.

  • Expected delivery: Q3 2026.

Due to semiconductor supply variability, pricing may vary. Estimated range:

  • €3,500 – €4,000 per unit.

Reservations are open to secure early units.

For inquiries, please contact WaveMasters at info@wavemasters.es

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