Models of the Earth's space debris and meteoroid environment need to be validated against measurement data such as the particle size, velocity and impact angle distributions. In particular the characteristics of the micron-sized particle regime is fairly unknown. Based on the requirement to measure the trajectory of fast micron-sized particles in space, a highly sensitive breadboard model of a particle trajectory analyser was developed. Basic requirements and considerations are outlined and the overall system design is described, which is based on the results of a numerical simulation of different configurations of the instrument. Some details of the optical, mechanical and electrical design of the instrument are given. A description of the test method is provided, which was developed for the characterisation of the breadboard model's performance. The general performance and calibration testing approach is outlined.