An airborne radar for three dimensional imaging and observation - technical realisation and status of ARTINO

Fraunhofer FHR

ABSTRACT Over the past years, the range of small unmanned arial vehicles (UAV) has increased steadily, and with it the interest to adopt them in earth observation, reconnaissance, monitoring, and surveillance missions by imaging systems. This paper presents the concept and status of a 3D imaging radar suitable for small UAVs. ARTINO combines a real aperture, realized by a linear array of nadir pointing antennas, and a synthetic aperture, which is spanned by the moving airplane. In consequence of the restricted payload the radar uses frequency modulated continuous wave (FMCW) technique with direct down-conversion in Ka band. Hence, the power consumption of the radar and the size of the antennas are reduced. In comparison to the standard complex and cost intensive phased array technique, it requires only a moderate number of antennas and microwave components. The scope of this paper is to present an overview of the front-end architecture, design, and realization status.

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    ABSTRACT: Based on the general geometric model of multi-baseline Synthetic Aperture Radar Tomography (TomoSAR), the three-dimensional (3-D) sampling criteria, the analytic expression of the 3-D Point Spread Function (PSF) and the 3-D resolution are derived in the 3-D wavenumber domain in this paper. Considering the relationship between the observation geometry and the size of illuminated scenario, a 3-D Range Migration Algorithm with Elevation Digital Spotlighting (RMA-EDS) is proposed. With this algorithm 3-D images of the area of interest can be directly and accurately reconstructed in the 3-D space avoiding the complex operations of 3-D geometric correction. Finally, theoretical analyses and simulation results are presented to demonstrate the shift-varying property of the 3-D PSF and the spatial-varying property of the 3-D resolution and to demonstrate the validity of the 3-D RMA-EDS.
    Science in China Series F Information Sciences 01/2009; 52:100-114. · 0.66 Impact Factor
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    ABSTRACT: This paper presents a three-dimensional (3D) range migration algorithm (RMA) suitable for downward-looking 3D-SAR with single-transmitting and multiple-receiving linear array antennas (STMR-LAA). As the round-trip range equation in 3D-SAR with STMR-LAA is a dual square root, the signal spectrum in 3D wavenumber domain contains nonlinear phase terms besides constant and linear phase terms. In this paper, the approximate expression of the signal spectrum is derived by expanding the implicit phase term to its Taylor series. Then the constant and nonlinear phase terms are calculated and compensated by multiplying the wavenumber filters. Finally, a 3D wavenumber mapping is proposed to make the signal evenly sampled in 3D wavenumber domain. Some simulating results are presented to validate the correctness of the analysis and the feasibility of the algorithm. In addition, the required accuracy on the platform position is analyzed at the end of the paper.