In assistive technology The simplest and the most affordable navigation and available tools are trained dogs and the white cane. Although these tools are very popular, they cannot provide the blind with all information and features for safe mobility, which are available to people with sight. Then came radar technology. Most are quite expensive but recently, a new low- cost radar technology developed by a team at King Abdullah University of Science and Technology (KAUST) and VTT Technical Research Center might just prove to be the answer. The radar is said to provide detailed information about the size, distance and speed of moving objects. However, for close-range applications, the transmitted radio waves must have short wavelengths to pick up as much detail as possible about its immediate environment. Such sensors could help visually impaired people by translating radar reflections into useful information.
"Current radar modules are large and bulky. They also lose out on key details because they operate using long radio wavelengths," said Seifallah Jardak, who worked on the project under the supervision of Sajid Ahmed and Mohamed-Slim Alouini from KAUST and along with Tero Kiuru and Mikko Metso from VTT. "We wanted to develop a low-power, portable radar. Colleagues at VTT brought the necessary experience in millimetre-wave and hardware design, while I focused on the signal processing side and developed modular radar software."
According to KAUST, an early prototype performed a single scan every two seconds, making it difficult to acquire enough input data. Jardak optimised the signal processing modules and improved the performance to eight scans per second, providing better real-time monitoring.
The device design incorporates a frequency-modulated continuous wave (FMCW) radar, which produces continuous pulses of millimetre-wavelength radio waves that have a frequency that varies during each pulse. The small wavelength means that the time taken for pulses to reach an object and reflect back are calculated accurately.
"To limit the size of our system, we chose an operating frequency of 24GHz. This enabled us to reduce the size of the microstrip antenna," said Jardak. "Our design also has one transmitting and two receiving antennae, meaning it can better estimate the angular location of a target."
The device fits into a 10cm box, weighs less than 150g and is powered by a 5V battery. Initial trials suggest the device is capable of target detection, speed estimation and tracking at ranges of up to 12m.
"Our prototype may also be useful for unmanned robotic and quadcopter applications where a collision avoidance system is required," said Jardak.
