In frequency modulated continuous wave sensor systems for object distance measurement, use of the fast Fourier transformation for frequency estimation is widely adopted because of its comparably low execution time and available implementations. Inherent resolution restrictions make modern state-space based frequency estimators a viable alternative to this approach. Estimation of the correct model order, crucial to accurate distance measurement when used in a setup with an unknown number of targets, may be avoided by using active transponders. In this paper, application of a state-space frequency estimator is investigated with the use of measurement data in a system with an a priori known number of active targets. Evaluation results are analyzed and compared to performance of the Fourier transformation.
This contribution describes the components necessary for measurement of the three-dimensional local position of objects with high accuracy and high measurement rate. The methodology is based on the FMCW (frequency modulated continuous wave) technology in state of the art technology described as sensor system. A high speed real-time network collects data and transfers it to a master processing unit (MPU) where 3-D position data is calculated. It is described how to measure and how to process position data for a local, wide area measurement system. Results are shown for a series of static measurements and an outdoor Motocross race.
In this paper a novel local position measurement (LPM) technology is presented. The LPM system operates in the 5GHz ISM band and consists of lightweight transponders of which the 3-D position is measured, and base stations located around the measurement field. Transponder and base stations operate similar to conventional radar systems and consist of RF electronics as well as signal processing elements. The RF-part in the transponders is the key element for the position measurement system. The measurement accuracy of the LPM system is in the range of some centimeters despite a high measurement rate of 1000 measurements per second.