Portable High Resolution LFM-CW Radar Sensor in Millimeter-Wave Band
ABSTRACT This paper presents a portable radar sensor developed in the Universidad Politecnica de Madrid. The system transmits a Linear Frequency Modulated Continuous Wave (LFM-CW) with two-antenna configuration for transmission and reception. The radar transmits at millimeter-wave band with a maximum bandwidth of 2 GHz and a transmitted power of 1 W. The system is modular, compact and lightweight. The sensor allows range intervals tuning and sampling the received signals with a constant rate. By this, it is particularly attractive for portable applications. Finally, the system performance has been tested in a traffic surveillance experiment.
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- "An INS unit is used to measure the aircraft motion. The MINISARA  from the Universidad Politécnica de Madrid is a portable SAR system with a center frequency of 34 GHz and a bandwidth of 2 GHz. The system is small (24 × 16 × 9 cm) and lightweight (2.5 kg). "
ABSTRACT: Small low-cost high-resolution synthetic aperture radar (SAR) systems are made possible by using a linear frequency-modulated continuous-wave (LFM-CW) signal. SAR processing assumes that the sensor is moving in a straight line at a constant speed, but in actuality, an unmanned aerial vehicle (UAV) or airplane will often significantly deviate from this ideal. This nonideal motion can seriously degrade the SAR image quality. In a continuous-wave system, this motion happens during the radar pulse, which means that existing motion compensation techniques that approximate the position as constant over a pulse are limited for LFM-CW SAR. Small aircraft and UAVs are particularly susceptible to atmospheric turbulence, making the need for motion compensation even greater for SARs operating on these platforms. In this paper, the LFM-CW SAR signal model is presented, and processing algorithms are discussed. The effects of nonideal motion on the SAR signal are derived, and new methods for motion correction are developed, which correct for motion during the pulse. These new motion correction algorithms are verified with simulated data and with actual data collected using the Brigham Young University muSAR system.IEEE Transactions on Geoscience and Remote Sensing 11/2008; DOI:10.1109/TGRS.2008.921958 · 3.51 Impact Factor
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ABSTRACT: This paper presents an experimental Synthetic Aperture Radar (SAR) system that is under development in the Universidad PolitÃƒÂ©cnica de Madrid. The system uses Linear Frequency Modulated Continuous Wave (LFM-CW) radar with a two antenna configuration for transmission and reception. The radar operates in the millimeter-wave band with a maximum transmitted bandwidth of 2 GHz. The proposed system is being developed for Unmanned Aerial Vehicle (UAV) operation. Motion errors in UAV operation can be critical. Therefore, this paper proposes a method for focusing SAR images with movement errors larger than the resolution cell. Typically, this problem is solved using two processing steps: first, coarse motion compensation based on the information provided by an Inertial Measuring Unit (IMU); and second, fine motion compensation for the residual errors within the resolution cell based on the received raw data. The proposed technique tries to focus the image without using data of an IMU. The method is based on a combination of the well known Phase Gradient Autofocus (PGA) for SAR imagery and typical algorithms for translational motion compensation on Inverse SAR (ISAR). This paper shows the first real experiments for obtaining high resolution SAR images using a car as a mobile platform for our radar.Sensors 05/2008; 8(5). DOI:10.3390/s8053384 · 2.05 Impact Factor
Conference Paper: Analysis of ISAR images of a helicopter by a facet model[Show abstract] [Hide abstract]
ABSTRACT: A triangular facet model of targets is proposed to generate ISAR images. Targets are composed of solid objects which are modeled by triangular facets. It is shown that the facets have an equivalent point-scatterer whose radar cross section and position depend on the shape of the triangle, the frequency and the angle of incidence. It is developed a shadowing algorithm to detect the facets which actually have influence on the signal received by the radar. This model is applied to study the ISAR images of a helicopter with two different transmitted signals, a rectangular pulse waveform and a linear frequency modulated waveform to identify the main features of the ISAR images for future classification purposes.Radar, 2008 International Conference on; 10/2008