Concept and realization of a low-cost multi-target simulator for CW and FMCW radar system calibration and testing

Abstract

We present the realization of an frequency-modulated continuous-wave radar target simulator, based on a modulated-reflector radar system. The simulator, designed for the 24 GHz frequency band, uses low-cost modulated-reflector nodes and is capable to simultaneously generate multiple targets in a real-time environment. The realization is based on a modular approach and thus provides a high scalability of the whole system. It is demonstrated that the concept is able to simulate multiple artificial targets, located at user-selectable ranges and even velocities, utilized within a completely static setup. The characterization of the developed hardware shows that the proposed concept allows to dynamically and precisely adjust the radar cross-section of each single target within a dynamic range of 50 dB. Additionally, the provided range-proportional target frequency bandwidth makes the system perfectly suitable for fast and reliable intermediate frequency-chain calibration of multi-channel radar systems. Within this paper we demonstrate the application of the concept for a linear sweeped frequency-modulated continuous-wave radar. The presented approach is applicable to any microwave-based measurement system using frequency differences between transmit- and receive signals for range- and velocity evaluation, such as (non-)linear sweeped as well as pure Doppler radar systems.

Flexible Direction-of-Arrival Simulation for Automotive Radar Target Simulators

“…The phase difference between the first and second RX antenna φ RX,2 (θ TE,n ) is calculated by (13). A Vandermonde matrix has a non-zero determinant if the values v n are distinct [19].…”

“…This means the approach enables the target simulator to generate as many targets with an individual DoA at the same time, as there are movable antennas. Another approach was presented in [13], where low-cost modulated reflectors have a fixed position and therefore simulate a fixed DoA. For an entire automotive scenario that might have a field of view of 60 • , this approach would require 30 target simulators for a resolution of 2 • .…”

“…Besides that, the restriction of a limited number of targets with individual DoA is resolved. The amount of required hardware is reduced significantly in comparison to a simulation environment that employs a target simulator for each simulated DoA [13]- [15]. The new concept is built on simple hardware and sophisticated signal processing, yielding a low-cost system.…”

Multitarget Simulator for Automotive Radar Sensors With Unknown Chirp-Sequence Modulation

“…Those systems realize the velocities of the targets by a frequency shift of the radar signal. A more flexible architecture, which is used for this target simulator as well, is a purely modulation-based simulator [8]- [11]. CS-FMCW radars allow the generation of ranges and velocities via modulation, since the evaluation of the time delay in the channel is measured indirectly via a frequency shift instead of measuring the time delay of the channel directly.…”

“…To determine the required frequency of the modulating signal, the knowledge of the modulation parameters of the radar is needed, namely the slope of the frequency ramp S and the ramp repetition frequency 1/T C . Compared to [8]- [10], where the modulation parameters were regarded as known, the presented target simulator is independent of a priori information, as the modulation parameters are estimated based on the first transmitted frequency ramps. In section II, the system concept is introduced, afterwards in section III the parameter estimation process is described.…”