Software Defined Radar (SDR) Basics

This page will define the basics of Software Defined Radar (SDR). We’ll go over a block diagram of a typical SDR system and explain the function of each module. We’ll also explore the advantages of using a software-defined architecture for radar applications.

What is Radar?

The term RADAR stands for RAdio Detection And Ranging. It’s primarily used to detect an object’s location, direction, and velocity.

What is Software Defined Radar?

A radar system whose internal modules can be configured via software is known as a software-defined radar. This approach leverages the flexibility and adaptability of software-defined radio (SDR) architectures.

Software Defined Radar Block Diagram

Here’s a look at the typical architecture of a software-defined radar system:

Figure 1: Software Defined Radar Block Diagram

As the diagram illustrates, the system is comprised of the following key modules:

1. RF/Microwave Section

This section handles the radio frequency signals and consists of several crucial components:

• Signal Conditioning Modules: These modules contain multiple channels and are responsible for processing analog signals.
• Up Converters (DUCs): Digital Up Converters translate baseband signals to higher RF frequencies for transmission.
• Down Converters (DDCs): Digital Down Converters translate received RF signals down to baseband for processing. For a detailed comparison, refer to resources discussing DUC vs DDC implementations.
• Local Oscillators: These are highly stable oscillators responsible for providing precise synchronization between the DUCs, DDCs, DACs, and ADCs within the system.
• Active Phased Array Antenna: This antenna array allows for flexible beam steering and control, enabling simultaneous transmission and reception of multiple radio signals.

2. IF/Baseband Section

This section focuses on the intermediate frequency (IF) and baseband signals:

• High Sample ADCs and DACs: These components are critical for converting between the analog and digital domains. They are chosen to support the wide bandwidths required by modern radar systems.
• ADCs (Analog-to-Digital Converters): ADCs convert the down-converted received data from analog to digital, preparing it for processing by the radar processor.
• DACs (Digital-to-Analog Converters): DACs convert the processed digital radar data back to analog, providing the necessary input for the up-converters before transmission. High sample rate ADCs/DACs can be used for direct sampling transmitter and direct sampling receiver designs.

3. Radar Processor and Data Storage Modules

• Radar Processor: Complex signal processing algorithms are developed and implemented on the processor used in the software-defined radar. This is where the “brains” of the radar reside, and where the data is interpreted to extract useful information.
• Data Storage Modules: These modules handle the storage of results and raw data according to user-defined requirements.

Advantages of Software Defined Radar Architecture

Using a software-defined approach for radar offers several key benefits:

• Rapid Prototyping and Testing: Software-configurable modules enable engineers to quickly prototype, test, and validate advanced radar systems using common hardware platforms. This significantly accelerates the development cycle.
• Leveraging SDR Ecosystem: SDR architectures benefit from the widespread availability of software-defined radio modules. This reduces development time and cost by allowing for easy integration of pre-built, readily available components.
• Wideband Signal Analysis: SDR allows for the analysis of radio signals with very wide bandwidths, enabling advanced radar techniques and improved performance.