A coherent multiple input multiple output (MIMO) radar system that uses the principles of a frequency modulated continuous wave (FMCW) radar and a time domain multiplexing technique can use a special modulation scheme to enable the unambiguous location estimation as well as a velocity estimation and compensation in a short measurement time [1]. To use this modulation scheme a special calibration procedure is needed. This strategy shall be displayed here.

For MIMO radar systems orthogonal waveforms are required to distinguish between the different transmitted signals at the different receivers. A hardware cost efficient way is the use of time-multiplexing, where the transmitters are active sequentially after each other. In the presence of platform or target movement, the sampling theorem in the spatial domain (along track) might not be fulfilled anymore which causes problems in the azimuth focusing. In this paper an interlaced switching scheme for a FMCW MIMO radar is proposed to overcome this issue. To verify the proposed method measurements were performed.

This paper covers the implementation of a near-range FMCW radar within a joint European scientific program for force protection from IEDs or landmines. The radar is one of four sensors whose data are fused and evaluated to provide a threat classification of suspicious objects or persons on or nearby the road ahead of a patrol or transport vehicle. A fully functionally low-cost demonstrator system has been implemented and successfully tested. Results are given.

Traditionally well-known from communication applications, the multiple-input multiple-output principle (MIMO) has found its way into radar system theory in the last years. Different arrangements of transceivers equipped with orthogonal signals, lead to arrangements of virtual elements which is denoted as virtual array in the context of coherent MIMO approaches. In order to proof practical feasibility of ongoing theoretical considerations, experiments have been started and evaluated.

For arrays the placement of the single elements determines the angular resolution and the unambiguity interval. The width of the total array determines the resolution capabilities. The wider the elements are placed from each other, the more space in Fourier domain is covered by the measurement and the resolution in time domain will improve. On the other hand the density of the elements has an effect on the angular interval in which objects can be detected unambiguously. For objects within the unambiguous interval grating lobes will appear outside this area while objects outside result in grating lobes in the interval of interest. In this paper the properties of arrays regarding resolution and unambiguity interval will be discussed and methods for the suppression of ambiguous grating lobes are suggested. One approach to suppress the influence of the grating lobes lies in the evaluation of different frequency bands.