• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.8
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• pp.1887-1894
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• 2010

This paper proposes a new switched-capacitor sigma-delta modulator for automotive radars. Developed modulator is used to perform high-resolution analog-to-digital conversion (ADC) of high frequency band signal in a radar system. It has supply voltage of 2.7V, and has body-effect compensated switch configuration with low voltage and low distortion. The modulator has been implemented in a $0.25{\mu}m$ double-poly and triple-metal standard CMOS process, and it has die area of $1.9{\times}1.5mm^{2}$. It showed better total harmonic distortion of 20dB than the conventional bootstrapped circuit at the supply voltage of 2.7V.

• ETRI Journal
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• v.43 no.4
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• pp.640-649
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• 2021

In this paper, an additional degree of freedom in phased multi-input multi-output (phased-MIMO) radar with any arbitrary desired covariance matrix is proposed using space-time codes. By using the proposed method, any desired transmit covariance matrix in MIMO radar (phased-MIMO radars) can be realized by employing fully correlated base waveforms such as phased-array radars and simply extending them to different time slots with predesigned phases and amplitudes. In the proposed method, the transmit covariance matrix depends on the base waveform and space-time codes. For simplicity, a base waveform can be selected arbitrarily (ie, all base waveforms can be fully correlated, similar to phased-array radars). Therefore, any desired covariance matrix can be achieved by using a very simple phased-array structure and space-time code in the transmitter. The main advantage of the proposed scheme is that it does not require diverse uncorrelated waveforms. This considerably reduces transmitter hardware and software complexity and cost. One the receiver side, multiple signals can be analyzed jointly in the time and space domains to improve the signal-to-interference-plus-noise ratio.

• Journal of the Korea Institute of Military Science and Technology
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• v.25 no.1
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• pp.23-29
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• 2022

As the application field of radar is expanded and the bandwidth increases, the number of radar sensors operating at the same frequency is continuously increasing. In this paper, we propose a method of analyzing interference when two pulse doppler radars are operated at the same frequency with different waveform which are designed independently. In addition, we show that even for a previously designed LFM waveforms, the interference can be suppressed without affecting the performance by changing the sign of the frequency slope by increasing/decreasing, or by modulating the pulses by the different codes. The interference suppression by different slopes is more effective for similar waveform and the suppression by the codes increases as the number of pulses increases. We expect this result can be extended to the cases where multiple radars are operated at the same frequency.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1998.06a
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• pp.718-721
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• 1998

• Ocean and Polar Research
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• v.34 no.4
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• pp.453-462
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• 2012

Ocean surface current data in Korea was collected using sets of High-Frequency Ocean Surface Radars (HFOSRs) with 25 radial sites in the frequency range of 5~43 MHz. Site selection and the correct installation of HFOSR are very important considerations in order to secure continuous and reliable results. The installation procedures of HFOSR are summarized as follows: 1. Survey area selection; 2. Investigation of ambient radio waves and installation environment; 3. Domestic license of radio station; 4. Installation of antenna and housing of electrical and communication devices. The current work describes the entire processes of HFOSR installation within Korea.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.474-477
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• 2005

In tactical theater, it is crucial to detect ground moving targets and to locate them precisely. This problem can be resolved by using SAR (Synthetic Aperture Radar) sensors providing GMTI (Ground Moving Target Indication) capability. In general, to implement a robust GMTI sensor is not simple because of the strong competitions between target signals and clutter signals on the ground, and low speed of moving targets. Contrary to the case that a delay canceller is mostly suitable for ground surveillance radars, DPCA (Displaced Phase Centered Antenna) or STAP (Space Time Adaptive Processing) techniques have been adapted for GMT! function of modem airborne radars. In this paper, anew scheme of DPCA using two passive antennas with vertical separation is proposed, which also provides good clutter cancellation performance. The proposed scheme enables us to scan straight ahead of the carrying platform that is impossible with typical DPCA configuration. Simulations using various conditions have been performed to validate the proposed scheme, and the results are acceptable.

• Journal of Advanced Marine Engineering and Technology
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• v.30 no.3
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• pp.444-448
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• 2006

In this paper, a frequency synthesizer for X-band FMCW radars is proposed. Some X-band FMCW radars have been used as a level sensor for tanker ship and the resolution of the level sensor may be mainly depend on linearity of frequency sweep. For a linear frequency sweep. the proposed synthesizer employs a phase-locked loop using prescalars and a high speed digital PLL chip. The measured results show that the linear frequency sweep range is from 10 GHz to 11 GHz and the output power of the synthesizer is minium 7 dBm. and the phase noise is about -80 dBc/Hz at 100 KHz offset from 11 GHz.

• IEMEK Journal of Embedded Systems and Applications
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• v.12 no.4
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• pp.223-229
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• 2017

An angle error is a factor obstructing to track accurate position in tracking radars. And the noise incurring the angle error can be divided as follows; thermal noise and glint. In general, Extended Kalman filter used in tracking radars is designed with considering thermal noise only. The Extended Klaman filter uses a fixed measurement error covariance when updating an estimate state by using ahead state and measurement. But, a noise power varies according to the range. Therefore we purposes the adaptive Kalman filter which changes the measurement noise covariance according to the range. In this paper, we compare the performance of the Extended Kalman filter and the proposed adaptive Kalman filter by considering KSLV-I (Korean Satellite Launch Vehicles).

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.10a
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• pp.258-259
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• 2018

The United States has deployed and operates a ballistic missile defense system to defend the homeland from ballistic missile attacks launched from direct and potential threats. The Missile Defense Agency has deployed the Aegis BMDs, Sea-based X-band radars(SBX), Ground-Based Interceptors(GBI), Early Warning Radars and THAADs. In addition, the Homeland Defense Radar-Hawaii(HDR-H) will be deployed in Hawaii. The HDR-H is expected to improve defensive ability to ballistic missile threats in the Asia-Pacific region.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.7
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• pp.1041-1048
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• 2012

We display important test information from radar, telemetry in real time for monitoring and control of guided missile flight test. Clearing test area is the most important thing for safety. Thus, we have to constantly monitor and control ships around the test area. Several maritime surveillance radars are deployed around the test area for that purpose. However, multiple points are displayed for the same target when using multiple surveillance radars and this confuses the test personnel during the mission. In this paper, we suggested a method to solve this problem by analyzing error factor of surveillance radar and comparing the correlation of each radar data.