Continuous navigation is crucial for small drones when flying a pre-planned route or during autonomous flight. In scenarios where a global positioning system (GPS) signal is unavailable, drift in the onboard sensors causes the inertial navigation system (INS) to quickly deviate from the planned route. This paper proposes a radar-aided navigation method for small drones which is able to estimate the horizontal velocity and height of the platform independently from GPS. The method is based on an omnidirectional radar system and takes advantage of multi-look processing to increase estimation precision. Simulations and experiments verify that an omnidirectional radar can be used to successfully estimate the velocity and course of a small drone platform.@en

In this paper, a wire detection algorithm is proposed for synthetic aperture radar (SAR) images. The algorithm is specifically designed for SAR images generated from an agile, drone-mounted, omnidirectional radar array to be used for the detection of improvised explosive devices (IEDs). A multistage approach consisting of denoising, constant false alarm rate (CFAR) thresholding, feature extraction, and automated detection using the Radon transform, is proposed and applied to a set of SAR images with multiple aspect angles. At each detection step, the look-angles of individual pixels are used to remove false alarms, and improve detection accuracy. The algorithm is tested using measured data and provides an acceptable detection performance on straight wire segments even in the presence of a strong background clutter. @en

In The Netherlands a demonstration small SAR instrument mission is prepared under the ESA Prodex program. Its launch is expected in 2017. The overall objective of this project is to demonstrate an alternative means to systematically assess the structural health of large volumes of infrastructure (built environment), in order to avoid hazardous situations. The assessment is based on an X-band interferometric Synthetic Aperture Radar with high resolution in the order of 2 meter. The radar system will be using the FMCW principle and will be realized within stringent Size, Weight and Power (SWAP) requirements in order to allow future missions of this type to be flown on small satellites. These future missions will possibly exploit the full FMCW capability in a formation flying sensor suite. The current demonstrator will consist of one platform with the instrument operating in Interrupted FMCW mode. This back-up mode is foreseen also for the future missions, in order to keep imaging capability in case one of the instruments in the formation has a serious malfunction. The paper describes the mission goal, the radar instrument and its performance.@en