At RFbeam we specialize in developing high-performance firmware for radar sensors. Collaborating closely with our hardware team we deliver radar modules tailored to our customers’ needs. In our broad portfolio of low-cost digital radar sensors, the requirement for high performance often meets the need for low cost and low power consumption. In these cases, microcontrollers are used because they can be precisely matched to the required memory capacity and computing power of an application. Our platform of choice for these tasks is the versatile STM32 family of microcontrollers.
Why STM32 Microcontrollers?
The STM32 family of microcontrollers from STMicroelectronics offers a wide range of devices that cater to different performance and power requirements. They are based on Arm Cortex-M cores, providing a good balance between processing power and energy efficiency. Additionally, the rich ecosystem of development tools and libraries makes them an excellent choice for complex projects like radar signal processing on microcontrollers.
Signal Processing Algorithms
The core of our software is the signal processing algorithms that extract meaningful information from the raw radar data. Our team brings years of experience and deep expertise in radar signal processing. Some of the techniques we employ include:
- Filtering: We use various filtering techniques to remove noise and unwanted signals.
- Fast Fourier Transform (FFT): FFT is a crucial algorithm for converting time-domain signals into frequency-domain signals, enabling us to analyze the velocity and range of targets.
- Constant False Alarm Rate (CFAR): CFAR algorithms help us detect targets in varying noise conditions, improving the reliability of our sensors. We choose between different CFAR algorithms depending on the application.
- Tracking: To enhance the reliability of target detections, we employ target tracking over multiple frames. This technique helps in maintaining consistent and accurate target information over time.
Memory Efficiency
Radar signal processing can be memory-intensive, but microcontrollers typically have limited RAM and flash storage. Here’s how we tackle this challenge:
- In-Place Operations: We design our algorithms to perform operations in-place, reusing memory buffers whenever possible.
- Efficient Data Structures: We choose data structures that are memory-efficient and tailored to our specific use cases.
- Direct Memory Transmission: We have developed our own protocol that can transmit sensor data directly from the memory location where it is calculated. This eliminates the need for intermediate buffering, further reducing memory usage and latency.
Low Power Design
Power consumption is a critical factor for radar sensor modules especially if they are low-cost. These modules are often used in battery-operated or remotely deployed devices. Here are some techniques we use to minimize power consumption:
- Power Modes: STM32 microcontrollers offer multiple power modes. We make use of these modes to put the device into a low-power state whenever possible.
- Efficient Algorithms: Our software is designed to perform the necessary computations in the least amount of time, allowing the device to spend more time in low-power modes.
Protocol for Stage-Wise Data Access
One of the standout features of our radar sensor software is our protocol that allows customers to read out computational results at each stage of the target-finding algorithm. This unique capability provides several advantages:
- Transparency: Customers can gain insights into the intermediate steps of the signal processing pipeline, from raw ADC data to tracked targets.
- Debugging and Validation: This feature is invaluable for debugging and validating the performance of the algorithm at each stage, ensuring accuracy and reliability.
- Customization: By accessing intermediate data, customers can tailor the algorithm to their specific needs, enhancing the flexibility of our solutions.
Tailored to Our Customers’ Needs
At RFbeam, we often customize our software to meet the specific needs of our customers. Whether it’s particularly low power consumption, special security requirements, or other specifications we can deliver. For a customer’s safety-critical application we have successfully delivered software compliant with Safety Integrity Level (SIL) standards. SIL is a measure of the reliability and safety of a system. Achieving SIL compliance ensures that our radar sensor software meets stringent safety requirements.
Conclusion
Radar software development on microcontrollers is a challenging but rewarding endeavor. At RFbeam we pride ourselves on our ability to deliver high-performance, low-power solutions tailored to our clients’ needs. Our expertise and experience in radar signal processing enables us to provide reliable and innovative radar sensor solutions. Take a look at our standard products https://rfbeam.ch/products/ or ask for a customized solution https://rfbeam.ch/support/ that fits your application.
