• Journal of Advanced Navigation Technology
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• v.25 no.5
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• pp.426-432
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• 2021

Continuous wave (CW) Doppler radar has the advantage of being able to solve the privacy problem unlike camera and obtains signals in a non-contact manner. Therefore, this paper proposes a human activity recognition (HAR) system using CW Doppler radar, and presents the hardware design and implementation results for acceleration. CW Doppler radar measures signals for continuous operation of human. In order to obtain a single motion spectrogram from continuous signals, an algorithm for counting the number of movements is proposed. In addition, in order to minimize the computational complexity and memory usage, binarized neural network (BNN) was used to classify human motions, and the accuracy of 94% was shown. To accelerate the complex operations of BNN, the FPGA-based BNN accelerator was designed and implemented. The proposed HAR system was implemented using 7,673 logics, 12,105 registers, 10,211 combinational ALUTs, and 18.7 Kb of block memory. As a result of performance evaluation, the operation speed was improved by 99.97% compared to the software implementation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.12
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• pp.2905-2910
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• 2015

CW Radar Sensors can be categorized into Single and Dual by its IF output type. Dual IF type is used for detecting the direction of moving objects. However, Dual IF type has more complicated circuitry than Single IF type and higher cost due to more parts required. In this paper, we propose an algorithm for Single IF type CW radar sensors to detect the direction of moving objects. It performs FFT on signals created at IF output when an object moves and determines approach, stop and recede according to amplitude variations. In order to verify the algorithm, a function generator is used to create a virtual signal and confirmed that it accurately detects the directions according to amplitude variations.

• Journal of Sensor Science and Technology
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• v.12 no.4
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• pp.185-190
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• 2003

Recently, sensors which use the infrared light, supersonic waves, and electromagnetic waves have been used for many applications to detect information of the object. For these sensors, the accompanying system which utilizes the sensor should be systematically developed. In this paper, a general microwave radar sensor system is briefly described, and then basic applications of a CW doppler radar sensor system are introduced. For the CW doppler radar sensor applications, a highly-stable, low-cost Dielectric Resonator Oscillator (DRO) has also been designed and implemented, which can be used for commercial microwave sensor systems. The implemented DRO has output power of +5.33 dBm at 12.67 GHz and phase noise of -108.5 dBc/Hz at the 100 kHz offset frequency.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.5
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• pp.460-470
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• 2009

In this paper, we described the implementation of the X-Band continuous-wave doppler radar for muzzle velocity measurement. The radar is consisted of microwave transceiver, signal processor, power board, and the measuring program was developed for the operating and field test. The operating frequency of doppler radar is able to set ${\pm}3\;MHz$ with 5 channel from the center frequency, and the output power is 25 dBm. The minimum receiving power is -117 dBm. The radar would obtain the doppler frequency from the artillery, and calculate accurate velocity point and then estimate muzzle velocity. The performance test for this radar was done with 155 mm at barrel and tripod mounted, and also compared the performance with the reference radar. As a result, the performance of the our new radar is equal with the reference one.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.999-1001
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• 2015

CW Doppler radar is capable of giving the relative velocity of an object using the Doppler effect. When detecting more than an object, frequency domain analysis is needed using CW Doppler radar and FFT. Even though the number of objects and velocities can be obtained within the frequency domain, there is a disadvantage that it is difficult to assess information on approach or deviation of an object. When detecting more than an object using FFT, this study suggests an algorithm for efficiently assessing information about approach or deviation of objects within the frequency domain. The proposed algorithm divides sections into real and imaginary numbers in the frequency domain, and then determines deviation if the total sum of the amplitudes of each frequency is on the left side and approach if the total sum of the amplitudes is on the right side.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.9
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• pp.1840-1846
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• 2011

It is necessary to estimate the Doppler spectrum for each range cell for the extraction of useful information from the return echoes in radar systems used for the remote sensing purpose such as detection of moving targets and weather surveillance. The signal amplitude in the beat frequency band is the important parameter in the detection and tracking of targets. However, strong clutter echoes do exist in most radar operation environments and the system phase noise spreads both the clutter and signal echoes of the target. In this paper, the effects of this system phase noise are analyzed concerning the clutter and the signal beat spectrum. It is shown that the separation capability of adjacent beat signal depends on the degree of spread in the clutter and beat signal caused by the radar system phase noise

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.11
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• pp.949-958
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• 2016

This paper presents the new development result of the multi-band, the multi-mode SDR(Software Defined Radar) platform. The SDR hardware platform is implemented by using the reconfigurable multi-band RF transceiver and antenna modules of S, X, and K-bands, and a programmable signal processing module. The SDR software platform is implemented by using the multi-mode waveform generation of CW, Pulse, FMCW, and LFM Chirp as well as the adaptable algorithm library of signal processing and open API software modules. Through the integrated test of the SDR platform, the operational performance was verified in real-time. Also, through the field-application test, the ground target and air-vehicle drone target were successfully detected and their test results were presented.

• Journal of Advanced Navigation Technology
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• v.26 no.4
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• pp.211-218
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• 2022

Continuous wave (CW) radar has the advantage of reliability and accuracy compared to other sensors such as camera and lidar. In addition, binarized neural network (BNN) has a characteristic that dramatically reduces memory usage and complexity compared to other deep learning networks. Therefore, this paper proposes binarized neural network based human identification and motion classification system using CW radar. After receiving a signal from CW radar, a spectrogram is generated through a short-time Fourier transform (STFT). Based on this spectrogram, we propose an algorithm that detects whether a person approaches a radar. Also, we designed an optimized BNN model that can support the accuracy of 90.0% for human identification and 98.3% for motion classification. In order to accelerate BNN operation, we designed BNN hardware accelerator on field programmable gate array (FPGA). The accelerator was implemented with 1,030 logics, 836 registers, and 334.904 Kbit block memory, and it was confirmed that the real-time operation was possible with a total calculation time of 6 ms from inference to transferring result.

• Journal of Satellite, Information and Communications
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• v.12 no.1
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• pp.34-37
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• 2017

This letter presents the signal processing of a CW radar (Continuous Wave or Doppler radar) sensor which enables the radar to detect the multiple targets' approaching and retreating using both I and Q channels. The proposed algorithm utilizes the phase change of the Quadrature signal, which occurs when targets move back and forth from the radar. The verification is carried out with the board containing a commercially available MMIC chip and an MCU by analyzing the received data from MMIC. Also the proposed algorithm is downloaded to MCU and the approaching and retreating movement is confirmed. The CW frequency is 24.125 GHz and the transmitter output power used is 7.2 dBm. Detectable distance is about 12 m.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.9
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• pp.1856-1863
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• 2012

Two separate antennas are usually adopted in high performance radar systems to achieve the high degree of isolation since the transmission and reception of signals cannot be separated in time. However, even though two spatially separated antennas are installed in the system, strong signals from a transmission antenna can cause the serious interference problem in a receiving antenna. These strong interference signals from the transmission antenna can cause serious problems in detection and analysis of much weaker echo signals which are reflected by small targets. Also the increased level of background noise power due to interference can cause the serious degradation of the system performance. Therefore, in this paper, the proper cancellation method is suggested and results are shown and analyzed for removal of strong interference and background noise power.