10.33012/2025.20442">
 

A One-Stop Solution for Multiple COTS SDR Pain Points: Multi-Channel Software-Defined Precision RF Calibration Module for Advanced GNSS Research and Development Applications

Document Type

Conference Proceeding

Publication Date

9-2025

Abstract

Most commercial-off-the-shelf software defined radio peripherals such as USRP are primarily designed for communications system applications. When adapting these for satnav, it is often necessary to place a myriad of additional components between the antenna(s) and the USRP to yield a practical solution. This incurs significant additional cost, a maze of modules and interconnect cables occupying additional space, and an overall sub-optimal solution that is hard to replicate for multiple campaigns where the equipment needs to be broken down and re-installed. In this paper we describe a single software-defined RF module that solves this tedious problem. The module performs the following functions: active antenna powering and precision LNA current monitoring; adapting one or more antennas to multiple outputs - each tuned to any sub-band in the 1-2 GHz range for additional selectivity and interference rejection; precision up-stream sub-band power monitoring and logging - that supports intelligent downstream software-defined gain control to avoid non-linear operation in the presence of interference; spectral monitoring and logging; precision digital gain and phase control; and the ability to precisely calibrate pairs of adjacent channels in gain and phase for applications such as dual polarized antenna systems. The module, measuring just 5.7 x 3.75 x 0.8 inches, is conveniently powered using Power-over-Ethernet and features per-channel precision current and temperature sensing and monitoring to support advanced timing-critical applications. The module's internal low power embedded microcontroller continuously monitors and logs all measurements, time tagged, into a built-in SD card. All functionality can be accessed via a standard web browser, or via an API that supports third party integration. In addition, the module can be used in stand-alone mode where nothing is connected to its RF outputs - or in 'sentry mode' where it is placed between the antenna(s) and receiver(s) employed in critical infrastructure such as banks, financial hubs, power stations, datacenters, and satnav monitoring stations. In this use case the module functions very much like a 'security webcam' for GNSS, offering realtime spectral situational awareness and irrefutable proof-of-interference for historical record, pattern-of-life analysis, or legal purposes. Abstract © ION.

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© 2025 ION GNSS. All rights reserved.

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Source Publication

38th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2025)

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