Low-Complexity Joint Range and Doppler FMCW Radar Algorithm Based on Number of Targets

Abstract

A low-complexity joint range and Doppler frequency-modulated continuous wave (FMCW) radar algorithm based on the number of targets is proposed in this paper. This paper introduces two low-complexity FMCW radar algorithms, that is, region of interest (ROI)-based and partial discrete Fourier transform (DFT)-based algorithms. We find the low-complexity condition of each algorithm by analyzing the complexity of these algorithms. From this analysis, it is found that the number of targets is an important factor in determining complexity. Based on this result, the proposed algorithm selects a low-complexity algorithm between two algorithms depending the estimated number of targets and thus achieves lower complexity compared two low-complexity algorithms introduced. The experimental results using real FMCW radar systems show that the proposed algorithm works well in a real environment. Moreover, central process unit time and count of float pointing are shown as a measure of complexity.clutter, there is no Doppler effect. Hence, two beat signals are the same except for noise term and thus the difference of two beat signals contains only noise term. On the other hand, in the case of moving target, there is Doppler effect due to the moving target and thus the difference of them contains the range information of moving target. However, this algorithm might miss the moving target with certain velocity because this algorithm fixedly employs two beat signals. In order to overcome this disadvantage, an FMCW radar algorithm has been proposed by randomly employing two beat signals in [14]. This algorithm effectively avoids missing a target with a certain velocity by randomly selecting two beat signals every frame. In addition, this algorithm performs an angle detection algorithm only if there is a moving target. Therefore, this algorithm reduces the overall complexity. However, this algorithm has still a disadvantage in that it does not detect the velocity of the target. This is because the difference between the two beat signals is used to reduce the complexity of the moving target detection process and in this process, information necessary for the velocity detection of the target is lost.Meanwhile, in [15][16][17][18], low-complexity detection algorithms for FMCW radar have been proposed which intend to reduce the number of FFTs compared to a full-dimension FFT-based FMCW radar algorithm. These algorithms determine a region of interest (ROI), thus reducing the number of inputs in the FFTs for Doppler estimation. However, there is still unnecessary computational complexity in these algorithms, although the complexity is reduced. The number of range bins used as the input in FFTs for Doppler estimation depends on the number of targets. In this algorithm, all chirp signals are used in an FFT to determine the range bins in which peaks exist. However, there is a disadvantage in that the number of range bins calculated in the first FFT for range estimation is too large compared to the number of range bins used as inputs in the FFT fo...

An Inclusive Survey of Contactless Wireless Sensing: A Technology Used for Remotely Monitoring Vital Signs Has the Potential to Combating COVID-19

“…Since the signals used in an FMCW-radar are sinusoidal, the FT is typically used to estimate parameters such as range, angle, and velocity. Depending on the number of parameters that need to be detected, the FT dimensions are adjusted accordingly [16]. For instance, to detect range and velocity a two-dimensional (2D) FT is required while a fourdimensional (4D) FT is needed to estimate range, velocity, azimuth, and elevation.…”

“…A base station s the aggregation of sensor network data onto a PC or computer platform. Any MICAz mote can function as a station when it is connected to a standard PC interface ateway board [16]. Our platform includes the MIB520 ay board which provides a serial/USB interface for both ramming and data communications.…”

“…The application provided has simply purpose to collect temperature and luminosity values red by sensors. Deployed network's map is illustrated in nodes which are close to the base station (15,16) have a higher percentage of transmitted packets that the ones that are far away. However, mote «4» which is also close to the base has a lower percentage.…”

An Elaborated Signal Model for Simultaneous Range and Vector Velocity Estimation in FMCW Radar

“…For correct use of the method of two-dimensional Fourier transform [ 19 , 20 , 21 ] and an unambiguous estimate of the velocity vector of a radar target, it is necessary that the phase change Φ V ( kT c ), calculated on the local time interval [0 ≤ t L ≤ T c ], does not exceed the value π. This requirement determines that the point θ belongs to the three-dimensional subspace Θ ( 3) 2 of the measured parameters { V R , V TR , R 2 } in the relation Equation (34).…”

“…The second method of simultaneous estimation of target speed and range is based on the use of two-dimensional (2D) Fourier transform [ 20 , 21 , 22 ]. It is easy to show that the dynamic range of measured velocities and distances using this method is proportional to the sampling rate f s of the analog IF signal: where R max and δR —maximum range and range resolution respectively, c —speed of light, V R max —maximum radial component of target velocity, f D max —Doppler frequency shift, that corresponds to maximum velocity V R max , and f 0 —the initial frequency of the radiated chirp radio signal.…”