Yong-Hee Kim - Academia.edu (original) (raw)

Papers by Yong-Hee Kim

We study on the attractive interaction between two atomic clouds, which leads to Spontaneous Symm... more We study on the attractive interaction between two atomic clouds, which leads to Spontaneous Symmetric Breaking (SSB) of atomic populations in the parametrically modulated magneto- optical trap (MOT). The parametric modulation is performed by periodically changing the intensity of laser beam along the axis of the anti-Helmholtz coils. In this parametrically modulated system, the two atomic clouds vibrate along the

Cold atoms have been widely used for the studies of many-body physics and critical phenomena in p... more Cold atoms have been widely used for the studies of many-body physics and critical phenomena in particular. However, most of the work on critical phenomena focused on systems effectively close to thermal equilibrium. Here we show that cold atoms make it possible to reveal and explore, qualitatively and quantitatively, critical behavior far from thermal equilibrium. We study periodically modulated atomic

We experimentally demonstrate the reversal transition of the order in a parametrically driven col... more We experimentally demonstrate the reversal transition of the order in a parametrically driven cold atomic system which shows ideal mean-field symmetry-breaking transition, by the application of the pulsed additional bias-field opposite to the pre-existing order. The strength h0 and the duration deltat of pulse are the control parameters of the reversal transition. We obtain the phase boundary of the transition

We report a simple method for trap parameter measurement by realizing forced harmonic oscillation... more We report a simple method for trap parameter measurement by realizing forced harmonic oscillation in a magneto-optical trap (MOT). Through the resonance curve of the vibrational amplitude of the harmonic oscillation on the driving frequency of the laser intensity, we measured the damping coefficient and trap frequency of trapped atoms in the MOT under various conditions and compared them with

Journal of thoracic disease, 2016

The aims of this study were to stratify the risk of recurrence based on the Masaoka-Koga stage an... more The aims of this study were to stratify the risk of recurrence based on the Masaoka-Koga stage and World Health Organization (WHO) classification systems after R0-resection for thymic epithelial tumors (TETs). A retrospective analysis was conducted on 479 patients who underwent surgery between Jan 1994 and Feb 2014 for TETs. The study group comprised 251 males and 228 females, with a median age of 52 years (range, 15-84 years). Of the 479 patients, 406 (84.8%) patients underwent R0-resection. Recurrence after R0-resection occurred in 32 patients during a median follow-up of 53 months (range, 2-227 months). A multivariate analysis revealed that the preoperative treatment including chemotherapy (P=0.036), Masaoka-Koga stage (P=0.011) and the WHO classification (P=0.001) were predictors for recurrence after R0-resection. Patients were stratified into four risk groups using a potential model incorporating both the Masaoka-Koga stage and WHO classifications. Group 1 comprised WHO types A...

Journal of thoracic disease, 2016

Lung cancer patients with idiopathic pulmonary fibrosis (IPF) are at a high risk of requiring lun... more Lung cancer patients with idiopathic pulmonary fibrosis (IPF) are at a high risk of requiring lung resection. The optimal surgical strategy for these patients remains unclear. This study aimed to compare the clinical results of a sublobar resection versus a lobectomy or more extensive resection for lung cancer in patients with IPF. From January 1995 to December 2012, 80 patients with simultaneous non-small cell lung cancer and IPF were treated surgically at Asan Medical Center. Predictors of recurrence-free survival and overall survival were evaluated in the series. Lobectomy or more extensive resection of the lung (lobar resection group) was performed in 65 patients and sublobar resection (sublobar resection group) was carried out in 15 patients. The sublobar resection group showed fewer in-hospital mortalities than the lobar resection group (6.7% vs. 15.4%; P=0.68). For late mortality after lung resection, cancer-related deaths were not significantly different in incidence between...

The Korean journal of internal medicine, Jan 14, 2016

Approximately 30% of esophageal cancer (EC) patients cannot complete endoscopic ultrasonography (... more Approximately 30% of esophageal cancer (EC) patients cannot complete endoscopic ultrasonography (EUS) due to malignant stricture (EUS non-traversability). This study examines clinical implications of EUS non-traversability in patients with advanced locoregional squamous EC receiving preoperative chemoradiotherapy (CRT) followed by esophagectomy. We retrieved data on 89 consecutive patients with advanced locoregional squamous EC (stage II or III). Relevant clinical and tumor-specific parameters were reviewed retrospectively. Significant factors affecting survival was determined by Cox regression analysis. EUS non-traversable EC was observed in 26 of 89 patients (29.2%). Median serum albumin level (3.6 g/dL vs. 3.9 g/dL, p = 0.028), tumor length (6.0 cm vs. 4.0 cm, p = 0.002), and percentage of clinical stage III disease (65.4% vs. 38.1%, p = 0.019) were significantly different between the patients with EUS non-traversable and traversable EC, respectively. Patients with EUS non-traver...

Journal of thoracic disease, 2016

We aimed to assess graft patency in patients undergoing prosthetic graft interposition of the bra... more We aimed to assess graft patency in patients undergoing prosthetic graft interposition of the brachiocephalic veins (BCVs) or the superior vena cava (SVC) combined with resection of malignant tumours. A retrospective analysis was conducted on 16 patients who underwent prosthetic graft interposition of the BCVs or the SVC between 1998 and 2012. Among a total of 20 grafts in 16 patients (unilateral graft interposition in 12, bilateral graft interposition in 4), 8 grafts were occluded in 8 patients. Overall graft patency rate was 64.6%, 42.4% at the 2- and 5-year follow-up. Graft patency rate of the left BCV was significantly lower than that of the right BCV or the SVC (2-year patency, 38.1% vs. 81.8%, P=0.024). In univariate analysis, the superior anastomosis site [left BCV vs. right BCV; hazard ratio (HR) =2.312; 95% confidence interval (CI), 1.015-5.265; P=0.046], the inferior anastomosis site (right atrial appendage vs. SVC; HR =2.409; 95% CI, 1.124-5.161; P=0.024), and interruptio...

PloS one, 2015

Developments of non-viral carriers have headed toward reducing cytotoxicity, which results from t... more Developments of non-viral carriers have headed toward reducing cytotoxicity, which results from the use of conventional gene carriers, and enhancing gene delivery efficiency. Cys-(d-R9)-Cys repeated reducible poly(oligo-D-arginine) (rPOA) is one of the most efficient non-viral carriers for gene therapy; however, while its efficiency has been verified in the lung and brain, it is necessary to confirm its activity in each organ or tissue since there are differences of gene carrier susceptibility to among tissue types. We therefore tested the compatibility of rPOA in cardiac tissue by in vitro or in vivo experiments and confirmed its high transfection efficiency and low cytotoxicity. Moreover, substantial regenerative effects were observed following transfection with rPOA/pVEGF expression vector complexes (79% decreased infarct size) compared to polyethyleneimine (PEI) (34% decreased infarct size) in a rat myocardial infarction (MI) model. These findings suggest that rPOA efficiently e...

The Thoracic and cardiovascular surgeon, Jan 15, 2015

Objectives Curative resection is not indicated for non-small cell lung cancer (NSCLC) with pleura... more Objectives Curative resection is not indicated for non-small cell lung cancer (NSCLC) with pleural seeding, which is classified as stage IV (M1a) disease. However, some patients with a presumably resectable main tumor are diagnosed with localized pleural seeding during surgery. Methods A retrospective analysis was performed of 3,975 patients who underwent surgery for NSCLC from 2000 to 2011. Among these cases, 78 (2.0%) patients had unexpected pleural seeding detected during surgery. Exploration with pleural biopsy was performed in 42 of these patients (exploration-only group) and pulmonary resection, including for the main tumor, was performed in 36 cases (resection group; sublobar resection in 12, lobectomy in 21, and pneumonectomy in 3 patients). Survival and cancer progression rates were estimated using the Kaplan-Meier method. Cox proportional hazard regression was used to evaluate prognostic factors associated with survival. Results Adenocarcinoma was the predominant histologi...

Surgical endoscopy, Jan 22, 2015

In patients with a mediastinal tumor, video-assisted thoracic surgery (VATS) is considered to be ... more In patients with a mediastinal tumor, video-assisted thoracic surgery (VATS) is considered to be associated with more postoperative advantages compared to open procedures. However, open procedures are still preferred in cases with large or malignant tumors. Therefore, in order to determine the appropriate surgical strategies for resection of teratomas, we here review our experience with such cases. Between January 2000 and February 2014, we experienced 132 patients diagnosed with mediastinal teratoma. By using data from a retrospective review of the patients' medical records, we compared the demographic characteristics, hospital stay duration, chest tube indwelling time, operative time, and mass size of the VATS group with those of the patients in the open group. Moreover, we also analyzed the postoperative complications and recurrence. Finally, based on our findings, we created a '∆V (volume of the mass-volume of the cyst in the mass)' capable of determining the appropr...

Computer Graphics and Imaging / 798: Signal Processing, Pattern Recognition and Applications, 2013

ABSTRACT In passive emitter location systems using the Time difference of arrival(TDOA) and Frequ... more ABSTRACT In passive emitter location systems using the Time difference of arrival(TDOA) and Frequency Difference of arrival(FDOA) measurements, the estimation performance varies with the geometric deployment and velocities of the sensors due to the high non-linearity of the TDOA/FDOA signal models, even when the estimation algorithm and the measurement error are not changed. To achieve a desired performance, finding appropriate deployment and velocities of the sensors is required. The problem is how to find them because there are too many cases of operating the emitter location systems. To cope with this problem, we derive an error ellipse to evaluate the estimation accuracy according to geometric deployment of the sensors based on the signal model in a 3-dimensional space (3-D) and various velocities. By using the derived error ellipse, analysis on the performance in the cases of several practical scenarios is carried out. The reliability of our evaluation method is confirmed by comparing to the performance evaluation based on the root-mean square error for the corresponding simulation results. Our analysis results on the various practical situations will be very helpful for operating the passive emitter location systems.

Although Spontaneous Symmetry Breaking (SSB) of atom clouds in parametrically driven Magneto-Opti... more Although Spontaneous Symmetry Breaking (SSB) of atom clouds in parametrically driven Magneto-Optical Trap (MOT) has been reported, the precise mechanism of SSB in atomic level is yet fully recognized. In this presentation, therefore, we explore the microscopic theory underlying the SSB phenomenon. Starting with the well-known process of change of variables followed by the method of averaging, we newly include

Nuclear Science and Engineering, 2003

The height-to-diameter (H/D) ratio of a lead-bismuth eutectic (LBE)-cooled accelerator-driven sys... more The height-to-diameter (H/D) ratio of a lead-bismuth eutectic (LBE)-cooled accelerator-driven system (ADS) has been evaluated in terms of the neutron multiplication, the coolant void worth, and the coolant velocity. For a model ADS, an optimization of the H/D ratio is performed with a Monte Carlo code both for the effective multiplication factor k{sub eff} and for the multiplication of the

Last decades of accomplishments in atomic physics are triggered by the invention of laser cooling... more Last decades of accomplishments in atomic physics are triggered by the invention of laser cooling and trapping technique of magneto optical trap. The studies on this trap revealed that there exist two kinds of forces therein so-called, Doppler and sub-Doppler force. We have found that with different detuning of trap laser between z axis and transverse axes, the normal sub-Doppler

In Korea, an accelerator-driven system (ADS) called HYPER (Hybrid Power Extraction Reactor) is be... more In Korea, an accelerator-driven system (ADS) called HYPER (Hybrid Power Extraction Reactor) is being studied for the transmutation of the radioactive wastes. HYPER is a 1 000 MWth lead- bismuth eutectic (LBE)-cooled ADS. In this paper, the neutronic design characteristics of HYPER are described and its transmutation performances are assessed for an equilibrium cycle. The core is loaded with a

In the passive emitter localization using instantaneous TDOA (time difference of arrival) and FDO... more In the passive emitter localization using instantaneous TDOA (time difference of arrival) and FDOA (frequency difference of arrival) measurements, the estimation accuracy can be improved by collecting additional measurements. To achieve this goal, it is required to increase the number of the sensors. However, in electronic warfare environment, a large number of sensors cause the loss of military strength due to high probability of intercept. Also, the additional processes should be considered such as the data link and the clock synchronization between the sensors. Hence, in this paper, the passive localization of a stationary emitter is presented by using the successive TDOA and FDOA measurements from two moving sensors. In this case, since an independent pair of sensors is added in the data set at every instant of measurement, each pair of sensors does not share the common reference sensor. Therefore, the QCLS (quadratic correction least squares) methods cannot be applied, in which...

The emitter geolocation method using the time difference of arrival (TDOA) and the frequency diff... more The emitter geolocation method using the time difference of arrival (TDOA) and the frequency difference of arrival (FDOA) has more accurate performance comparing to the single TDOA or FDOA based method. The estimation performance varies with the sensor paring strategies, the deployment and velocities of the sensors. Therefore, to establish effective strategy on the electronic warfare system, it is required to analyze the relation between the estimation accuracy and the operational condition of sensors. However, in the conventional non-iterative method, the restriction of the deployment of sensors and the reference sensor exists. Therefore, we derive the emitter geolocation method based on a Gauss-Newton method which is available to apply to any various sensor pairs and the deployment and velocities of the sensors. In addition, simulation results are included to compare the performance of geolocation method according to the used measurements: the combined TDOA/FDOA, TDOA, and FDOA. A...

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We study on the attractive interaction between two atomic clouds, which leads to Spontaneous Symm... more We study on the attractive interaction between two atomic clouds, which leads to Spontaneous Symmetric Breaking (SSB) of atomic populations in the parametrically modulated magneto- optical trap (MOT). The parametric modulation is performed by periodically changing the intensity of laser beam along the axis of the anti-Helmholtz coils. In this parametrically modulated system, the two atomic clouds vibrate along the

Cold atoms have been widely used for the studies of many-body physics and critical phenomena in p... more Cold atoms have been widely used for the studies of many-body physics and critical phenomena in particular. However, most of the work on critical phenomena focused on systems effectively close to thermal equilibrium. Here we show that cold atoms make it possible to reveal and explore, qualitatively and quantitatively, critical behavior far from thermal equilibrium. We study periodically modulated atomic

We experimentally demonstrate the reversal transition of the order in a parametrically driven col... more We experimentally demonstrate the reversal transition of the order in a parametrically driven cold atomic system which shows ideal mean-field symmetry-breaking transition, by the application of the pulsed additional bias-field opposite to the pre-existing order. The strength h0 and the duration deltat of pulse are the control parameters of the reversal transition. We obtain the phase boundary of the transition

We report a simple method for trap parameter measurement by realizing forced harmonic oscillation... more We report a simple method for trap parameter measurement by realizing forced harmonic oscillation in a magneto-optical trap (MOT). Through the resonance curve of the vibrational amplitude of the harmonic oscillation on the driving frequency of the laser intensity, we measured the damping coefficient and trap frequency of trapped atoms in the MOT under various conditions and compared them with

Journal of thoracic disease, 2016

The aims of this study were to stratify the risk of recurrence based on the Masaoka-Koga stage an... more The aims of this study were to stratify the risk of recurrence based on the Masaoka-Koga stage and World Health Organization (WHO) classification systems after R0-resection for thymic epithelial tumors (TETs). A retrospective analysis was conducted on 479 patients who underwent surgery between Jan 1994 and Feb 2014 for TETs. The study group comprised 251 males and 228 females, with a median age of 52 years (range, 15-84 years). Of the 479 patients, 406 (84.8%) patients underwent R0-resection. Recurrence after R0-resection occurred in 32 patients during a median follow-up of 53 months (range, 2-227 months). A multivariate analysis revealed that the preoperative treatment including chemotherapy (P=0.036), Masaoka-Koga stage (P=0.011) and the WHO classification (P=0.001) were predictors for recurrence after R0-resection. Patients were stratified into four risk groups using a potential model incorporating both the Masaoka-Koga stage and WHO classifications. Group 1 comprised WHO types A...

Journal of thoracic disease, 2016

Lung cancer patients with idiopathic pulmonary fibrosis (IPF) are at a high risk of requiring lun... more Lung cancer patients with idiopathic pulmonary fibrosis (IPF) are at a high risk of requiring lung resection. The optimal surgical strategy for these patients remains unclear. This study aimed to compare the clinical results of a sublobar resection versus a lobectomy or more extensive resection for lung cancer in patients with IPF. From January 1995 to December 2012, 80 patients with simultaneous non-small cell lung cancer and IPF were treated surgically at Asan Medical Center. Predictors of recurrence-free survival and overall survival were evaluated in the series. Lobectomy or more extensive resection of the lung (lobar resection group) was performed in 65 patients and sublobar resection (sublobar resection group) was carried out in 15 patients. The sublobar resection group showed fewer in-hospital mortalities than the lobar resection group (6.7% vs. 15.4%; P=0.68). For late mortality after lung resection, cancer-related deaths were not significantly different in incidence between...

The Korean journal of internal medicine, Jan 14, 2016

Approximately 30% of esophageal cancer (EC) patients cannot complete endoscopic ultrasonography (... more Approximately 30% of esophageal cancer (EC) patients cannot complete endoscopic ultrasonography (EUS) due to malignant stricture (EUS non-traversability). This study examines clinical implications of EUS non-traversability in patients with advanced locoregional squamous EC receiving preoperative chemoradiotherapy (CRT) followed by esophagectomy. We retrieved data on 89 consecutive patients with advanced locoregional squamous EC (stage II or III). Relevant clinical and tumor-specific parameters were reviewed retrospectively. Significant factors affecting survival was determined by Cox regression analysis. EUS non-traversable EC was observed in 26 of 89 patients (29.2%). Median serum albumin level (3.6 g/dL vs. 3.9 g/dL, p = 0.028), tumor length (6.0 cm vs. 4.0 cm, p = 0.002), and percentage of clinical stage III disease (65.4% vs. 38.1%, p = 0.019) were significantly different between the patients with EUS non-traversable and traversable EC, respectively. Patients with EUS non-traver...

Journal of thoracic disease, 2016

We aimed to assess graft patency in patients undergoing prosthetic graft interposition of the bra... more We aimed to assess graft patency in patients undergoing prosthetic graft interposition of the brachiocephalic veins (BCVs) or the superior vena cava (SVC) combined with resection of malignant tumours. A retrospective analysis was conducted on 16 patients who underwent prosthetic graft interposition of the BCVs or the SVC between 1998 and 2012. Among a total of 20 grafts in 16 patients (unilateral graft interposition in 12, bilateral graft interposition in 4), 8 grafts were occluded in 8 patients. Overall graft patency rate was 64.6%, 42.4% at the 2- and 5-year follow-up. Graft patency rate of the left BCV was significantly lower than that of the right BCV or the SVC (2-year patency, 38.1% vs. 81.8%, P=0.024). In univariate analysis, the superior anastomosis site [left BCV vs. right BCV; hazard ratio (HR) =2.312; 95% confidence interval (CI), 1.015-5.265; P=0.046], the inferior anastomosis site (right atrial appendage vs. SVC; HR =2.409; 95% CI, 1.124-5.161; P=0.024), and interruptio...

PloS one, 2015

Developments of non-viral carriers have headed toward reducing cytotoxicity, which results from t... more Developments of non-viral carriers have headed toward reducing cytotoxicity, which results from the use of conventional gene carriers, and enhancing gene delivery efficiency. Cys-(d-R9)-Cys repeated reducible poly(oligo-D-arginine) (rPOA) is one of the most efficient non-viral carriers for gene therapy; however, while its efficiency has been verified in the lung and brain, it is necessary to confirm its activity in each organ or tissue since there are differences of gene carrier susceptibility to among tissue types. We therefore tested the compatibility of rPOA in cardiac tissue by in vitro or in vivo experiments and confirmed its high transfection efficiency and low cytotoxicity. Moreover, substantial regenerative effects were observed following transfection with rPOA/pVEGF expression vector complexes (79% decreased infarct size) compared to polyethyleneimine (PEI) (34% decreased infarct size) in a rat myocardial infarction (MI) model. These findings suggest that rPOA efficiently e...

The Thoracic and cardiovascular surgeon, Jan 15, 2015

Objectives Curative resection is not indicated for non-small cell lung cancer (NSCLC) with pleura... more Objectives Curative resection is not indicated for non-small cell lung cancer (NSCLC) with pleural seeding, which is classified as stage IV (M1a) disease. However, some patients with a presumably resectable main tumor are diagnosed with localized pleural seeding during surgery. Methods A retrospective analysis was performed of 3,975 patients who underwent surgery for NSCLC from 2000 to 2011. Among these cases, 78 (2.0%) patients had unexpected pleural seeding detected during surgery. Exploration with pleural biopsy was performed in 42 of these patients (exploration-only group) and pulmonary resection, including for the main tumor, was performed in 36 cases (resection group; sublobar resection in 12, lobectomy in 21, and pneumonectomy in 3 patients). Survival and cancer progression rates were estimated using the Kaplan-Meier method. Cox proportional hazard regression was used to evaluate prognostic factors associated with survival. Results Adenocarcinoma was the predominant histologi...

Surgical endoscopy, Jan 22, 2015

In patients with a mediastinal tumor, video-assisted thoracic surgery (VATS) is considered to be ... more In patients with a mediastinal tumor, video-assisted thoracic surgery (VATS) is considered to be associated with more postoperative advantages compared to open procedures. However, open procedures are still preferred in cases with large or malignant tumors. Therefore, in order to determine the appropriate surgical strategies for resection of teratomas, we here review our experience with such cases. Between January 2000 and February 2014, we experienced 132 patients diagnosed with mediastinal teratoma. By using data from a retrospective review of the patients' medical records, we compared the demographic characteristics, hospital stay duration, chest tube indwelling time, operative time, and mass size of the VATS group with those of the patients in the open group. Moreover, we also analyzed the postoperative complications and recurrence. Finally, based on our findings, we created a '∆V (volume of the mass-volume of the cyst in the mass)' capable of determining the appropr...

Computer Graphics and Imaging / 798: Signal Processing, Pattern Recognition and Applications, 2013

ABSTRACT In passive emitter location systems using the Time difference of arrival(TDOA) and Frequ... more ABSTRACT In passive emitter location systems using the Time difference of arrival(TDOA) and Frequency Difference of arrival(FDOA) measurements, the estimation performance varies with the geometric deployment and velocities of the sensors due to the high non-linearity of the TDOA/FDOA signal models, even when the estimation algorithm and the measurement error are not changed. To achieve a desired performance, finding appropriate deployment and velocities of the sensors is required. The problem is how to find them because there are too many cases of operating the emitter location systems. To cope with this problem, we derive an error ellipse to evaluate the estimation accuracy according to geometric deployment of the sensors based on the signal model in a 3-dimensional space (3-D) and various velocities. By using the derived error ellipse, analysis on the performance in the cases of several practical scenarios is carried out. The reliability of our evaluation method is confirmed by comparing to the performance evaluation based on the root-mean square error for the corresponding simulation results. Our analysis results on the various practical situations will be very helpful for operating the passive emitter location systems.

Although Spontaneous Symmetry Breaking (SSB) of atom clouds in parametrically driven Magneto-Opti... more Although Spontaneous Symmetry Breaking (SSB) of atom clouds in parametrically driven Magneto-Optical Trap (MOT) has been reported, the precise mechanism of SSB in atomic level is yet fully recognized. In this presentation, therefore, we explore the microscopic theory underlying the SSB phenomenon. Starting with the well-known process of change of variables followed by the method of averaging, we newly include

Nuclear Science and Engineering, 2003

The height-to-diameter (H/D) ratio of a lead-bismuth eutectic (LBE)-cooled accelerator-driven sys... more The height-to-diameter (H/D) ratio of a lead-bismuth eutectic (LBE)-cooled accelerator-driven system (ADS) has been evaluated in terms of the neutron multiplication, the coolant void worth, and the coolant velocity. For a model ADS, an optimization of the H/D ratio is performed with a Monte Carlo code both for the effective multiplication factor k{sub eff} and for the multiplication of the

Last decades of accomplishments in atomic physics are triggered by the invention of laser cooling... more Last decades of accomplishments in atomic physics are triggered by the invention of laser cooling and trapping technique of magneto optical trap. The studies on this trap revealed that there exist two kinds of forces therein so-called, Doppler and sub-Doppler force. We have found that with different detuning of trap laser between z axis and transverse axes, the normal sub-Doppler

In Korea, an accelerator-driven system (ADS) called HYPER (Hybrid Power Extraction Reactor) is be... more In Korea, an accelerator-driven system (ADS) called HYPER (Hybrid Power Extraction Reactor) is being studied for the transmutation of the radioactive wastes. HYPER is a 1 000 MWth lead- bismuth eutectic (LBE)-cooled ADS. In this paper, the neutronic design characteristics of HYPER are described and its transmutation performances are assessed for an equilibrium cycle. The core is loaded with a

In the passive emitter localization using instantaneous TDOA (time difference of arrival) and FDO... more In the passive emitter localization using instantaneous TDOA (time difference of arrival) and FDOA (frequency difference of arrival) measurements, the estimation accuracy can be improved by collecting additional measurements. To achieve this goal, it is required to increase the number of the sensors. However, in electronic warfare environment, a large number of sensors cause the loss of military strength due to high probability of intercept. Also, the additional processes should be considered such as the data link and the clock synchronization between the sensors. Hence, in this paper, the passive localization of a stationary emitter is presented by using the successive TDOA and FDOA measurements from two moving sensors. In this case, since an independent pair of sensors is added in the data set at every instant of measurement, each pair of sensors does not share the common reference sensor. Therefore, the QCLS (quadratic correction least squares) methods cannot be applied, in which...

The emitter geolocation method using the time difference of arrival (TDOA) and the frequency diff... more The emitter geolocation method using the time difference of arrival (TDOA) and the frequency difference of arrival (FDOA) has more accurate performance comparing to the single TDOA or FDOA based method. The estimation performance varies with the sensor paring strategies, the deployment and velocities of the sensors. Therefore, to establish effective strategy on the electronic warfare system, it is required to analyze the relation between the estimation accuracy and the operational condition of sensors. However, in the conventional non-iterative method, the restriction of the deployment of sensors and the reference sensor exists. Therefore, we derive the emitter geolocation method based on a Gauss-Newton method which is available to apply to any various sensor pairs and the deployment and velocities of the sensors. In addition, simulation results are included to compare the performance of geolocation method according to the used measurements: the combined TDOA/FDOA, TDOA, and FDOA. A...

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