What Is a Software-Defined GNSS Receiver? Architecture, Benefits, and Use Cases
Locus Lock develops high-performance, computationally efficient software-defined GNSS receivers for aerospace, defense, and autonomous systems. Built on decades of research, our technology combines advanced signal processing algorithms, flexible software architecture, and general-purpose computing hardware to deliver precise, resilient positioning in challenging operating environments.
1. What Is a Software-Defined GNSS Receiver?
A software-defined GNSS receiver (SDR) is a satellite navigation receiver that implements its core signal processing functions in software rather than relying on dedicated, fixed-function GNSS receiver hardware. These functions include satellite signal acquisition, tracking, navigation data decoding, measurement generation, and position, velocity, and time (PVT) estimation.
Locus Lock's Leo200 GNSS SDR implements this concept with three components:
| Component | Role | What it does |
|---|---|---|
| RFx · RF Front End | Signal Capture | Receives, downconverts, and digitizes GNSS signals, then outputs raw RF samples for processing |
| PpRx · Software | Signal Processing | Processes raw RF samples to perform satellite signal acquisition, tracking, measurement generation, and PVT estimation |
| General Purpose Compute | Signal Processing | Runs PpRx in real time, often alongside downstream applications such as additional navigators, path planning, guidance, and control |
Together, these components provide a complete, turn-key GNSS receiver solution.
2. Why Use a Software-Defined GNSS Receiver?
Flexibility
A primary advantage of a software-defined GNSS receiver is its flexibility. Rather than requiring applications to conform to the interfaces and capabilities of a fixed-function receiver, a software-defined architecture is easily configured and adapted to meet application-specific requirements.
Leo200's software-defined architecture provides flexibility across several areas:
| Flexibility feature | How it works |
|---|---|
| Seamless system integration | Customizable PpRx software interfaces enable integration with existing flight computers, navigation systems, and downstream applications. |
| Flexible RF inputs | The underlying PpRx software can support a range of RF front-ends and digitized sample formats, including different sampling rates, quantization schemes, and bit-packing formats. |
| Mission-specific configuration | Receiver parameters can be configured for specific operating conditions at runtime, including vehicle dynamics, GNSS signal selection, initialization, and external sensor aiding. |
This flexibility allows engineering teams to readily integrate advanced GNSS capabilities into existing platforms and tailor receiver behavior to their requirements.
High Performance and Continuous Improvement
Modern general-purpose processors enable high-performance GNSS signal processing entirely in software.
In Leo200, all GNSS processing downstream of RF sampling and quantization is performed by the PpRx software. The highly optimized signal-processing stack within PpRx enables real-time operation on low-SWaP (size, weight, and power) computing platforms.
Futhermore, receiver capabilities are not fixed at the time of deployment.
As Locus Lock develops new features, expands signal support, and implements improved signal-processing algorithms, these advancements can be rapidly delivered through software updates without requiring hardware replacement.
This adaptability is particularly valuable in contested RF environments, where evolving jamming and spoofing threats may require new signal-processing techniques and countermeasures.
Low-Cost Development and Deployment
Software-defined GNSS receivers can reduce costs throughout the development and production lifecycle by minimizing specialized hardware requirements and simplifying system integration.
Integration and Development
Leo200 provides a ready-to-use combination of PpRx software, RFx hardware, and general-purpose compute, allowing engineering teams to rapidly evaluate capabilities without developing their own receiver architecture.
For applications requiring additional customization, software-based receiver functionality can be changed without the cost, time, and effort associated with developing new GNSS receiver hardware.
Production and Deployment
Conventional receivers typically rely on dedicated hardware for GNSS signal processing. In contrast, the PpRx software can run onboard general-purpose compute already available on many embedded platforms, simplifying system architectures and reducing production hardware costs.
3. Get Started with Software-Defined GNSS
Locus Lock's Leo200 provides a straightforward path from initial evaluation to deployment. Explore Leo200 and purchase directly through our website, or contact our team to discuss your application and integration requirements.
