scholarly journals An approach of constant false alarm ratio for improved target tracking

2020 ◽  
Vol 70 (3) ◽  
pp. 17-23
Author(s):  
Zvonko Radosavljević ◽  
Dejan Ivković
Keyword(s):  
False Alarm ◽  
Tracking Error ◽  
Probability Of Detection ◽  
Interacting Multiple Model ◽  
Multiple Model ◽  
Moving Targets ◽  
False Alarm Ratio ◽  
Motion Models ◽  
Areas Of Interest

Each radar has the function of surveillance of certain areas of interest. In particular, the radar also has the function of tracking moving targets in that territory with some probability of detection, which depends on the type of detector. Constant false alarm ratio (CFAR) is a very commonly used detector. Changing the probability of target detection can directly affect the quality of tracking the moving targets. The paper presents the theoretical basis of the influence of CFAR detectors on the quality of tracking, as well as an approach to the selection of CFAR detectors, CATM CFAR, which enables better monitoring by the Interacting Multiple Model (IMM) algorithm with two motion models. Comparative analysis of CA and CATM algorithm realized by numerical simulations has shown that CATM CFAR gives less tracking error with proportionally the same computer resources.

The Application of IMM-PF in Airport Surface Moving Target Tracking

2014 ◽  
Vol 1056 ◽  
pp. 240-243
Author(s):  
Qian Chen ◽  
Bang Feng Wang ◽  
Shu Lin Liu
Keyword(s):  
Target Tracking ◽  
Moving Target ◽  
Interacting Multiple Model ◽  
Multiple Model ◽  
Moving Targets ◽  
Constant Acceleration ◽  
Moving Target Tracking ◽  
Motion Models ◽  
Ca Model ◽  
Cv Model

In order to improve the accuracy of surveillance for the airport surface moving targets, the interacting multiple model (IMM) algorithm, adopting three motion models including the constant velocity (CV) model, the constant acceleration (CA) model and the constant turning (CT) model, is combined with the particle filter (PF) algorithm. Besides, the airport map information is utilized to amend the measured data and the output estimates so as to further improve the accuracy of airport surface moving target tracking. Numerical simulations show that the improved algorithm described in this paper is more feasible and effective in tracking the airport surface moving targets.

The Influence of Weather Watch Type on the Quality of Tornado Warnings and its Implications for Future Forecasting Systems

2021 ◽  
Author(s):  
Makenzie J. Krocak ◽  
Harold E. Brooks
Keyword(s):  
False Alarm ◽  
Lead Time ◽  
Severe Weather ◽  
Probability Of Detection ◽  
False Alarm Ratio ◽  
Tornado Warnings ◽  
General Improvement ◽  
The Difference ◽  
Tornado Warning

AbstractWhile many studies have looked at the quality of forecast products, few have attempted to understand the relationship between them. We begin to consider whether or not such an influence exists by analyzing storm-based tornado warning product metrics with respect to whether they occurred within a severe weather watch and, if so, what type of watch they occurred within.The probability of detection, false alarm ratio, and lead time all show a general improvement with increasing watch severity. In fact, the probability of detection increased more as a function of watch-type severity than the change in probability of detection during the time period of analysis. False alarm ratio decreased as watch type increased in severity, but with a much smaller magnitude than the difference in probability of detection. Lead time also improved with an increase in watch-type severity. Warnings outside of any watch had a mean lead time of 5.5 minutes, while those inside of a particularly dangerous situation tornado watch had a mean lead time of 15.1 minutes. These results indicate that the existence and type of severe weather watch may have an influence on the quality of tornado warnings. However, it is impossible to separate the influence of weather watches from possible differences in warning strategy or differences in environmental characteristics that make it more or less challenging to warn for tornadoes. Future studies should attempt to disentangle these numerous influences to assess how much influence intermediate products have on downstream products.

scholarly journals Long-Term Performance Metrics for National Weather Service Tornado Warnings

2018 ◽  
Vol 33 (6) ◽  
pp. 1501-1511 ◽  
Author(s):  
Harold E. Brooks ◽  
James Correia
Keyword(s):  
False Alarm ◽  
Lead Time ◽  
Performance Metrics ◽  
Warning System ◽  
Probability Of Detection ◽  
False Alarms ◽  
National Weather Service ◽  
False Alarm Ratio ◽  
Tornado Warnings ◽  
Weather Service

Abstract Tornado warnings are one of the flagship products of the National Weather Service. We update the time series of various metrics of performance in order to provide baselines over the 1986–2016 period for lead time, probability of detection, false alarm ratio, and warning duration. We have used metrics (mean lead time for tornadoes warned in advance, fraction of tornadoes warned in advance) that work in a consistent way across the official changes in policy for warning issuance, as well as across points in time when unofficial changes took place. The mean lead time for tornadoes warned in advance was relatively constant from 1986 to 2011, while the fraction of tornadoes warned in advance increased through about 2006, and the false alarm ratio slowly decreased. The largest changes in performance take place in 2012 when the default warning duration decreased, and there is an apparent increased emphasis on reducing false alarms. As a result, the lead time, probability of detection, and false alarm ratio all decrease in 2012. Our analysis is based, in large part, on signal detection theory, which separates the quality of the warning system from the threshold for issuing warnings. Threshold changes lead to trade-offs between false alarms and missed detections. Such changes provide further evidence for changes in what the warning system as a whole considers important, as well as highlighting the limitations of measuring performance by looking at metrics independently.

Synthesis of an algorithm for increasing the detection range of signals from radio-electronic means by means of radio control based on the estimated-correlation-compensation processing of signals with an unknown shape and additive noise in the receiving channel

2021 ◽  
Author(s):  
А.А. Boldyrev ◽  
А.А. Buben’shikov ◽  
D.I. Boldyrev
Keyword(s):  
False Alarm ◽  
Rapid Development ◽  
Internal Noise ◽  
Probability Of Detection ◽  
Detection Range ◽  
Signal Noise ◽  
Radio Electronic ◽  
Wide Range ◽  
Technical Systems

In modern conditions of rapid development of telecommunication technologies radio engineering means of different function are used everywhere in all spheres of ability to live of the person. Thus organizational-technical systems of civil appointment and power departments use the wide nomenclature of radio-electronic means of various classes with a wide spectrum of parameters, kinds of radiations and operating modes. In turn, it causes formation of difficult electromagnetic conditions in administrative-industrial regions and their near environment. The primary goal of services of radio control in these conditions is control over correctness of use by organizational-technical systems of the allocated resource of a radiofrequency spectrum and the parameters radiating of radio-electronic means. One of the main difficulties with which means of radio control in the course of the analysis of electromagnetic conditions in the set territorial area face a considerable quantity of radiating radio-electronic means with various parameters in a wide range of the relation a signal/noise, and also presence of stirring influence of any hindrances is. These factors make rigid demands to indicators of quality of functioning of panoramic detectors-direction finders which make a basis of mobile and stationary means of radio control. One of the basic indicators of quality of panoramic detectors-direction finders of means of radio control is range of detection of the radio-electronic means, defined by the set level of sensitivity and demanded values of probabilities of detection and a false alarm. Authors in article result results of working out of algorithm of increase of range of detection of signals by means of radio control on the basis of an estimated-correlation-compensatory way of measurement and indemnification of average capacity of additive hindrances in the reception channel. By results of the researches spent in article it is shown that: the increase in average capacity of cumulative external inadvertent and deliberate hindrances for the set typical initial data leads in VHF a range to reduction of range of detection of radio-electronic means not less, than in 1,4 times from the demanded; at demanded value of probability of detection, for example, and probabilities of a false alarm, at relative level of external set of a hindrance the panoramic detectors-direction finder of means of radio control with the realised procedure of measurement and indemnification of average value of capacity (dispersion) of inadvertent, deliberate hindrances and internal noise allows to lower the requirement to the threshold relation a signal/(noise) (on pressure) more, than in 1,3 times that will allow to approach value of range of detection to a reference value.

Interacting Multiple Model LK Tracking

2014 ◽  
Vol 644-650 ◽  
pp. 1733-1736
Author(s):  
Hong Wang ◽  
Jia Deng
Keyword(s):  
Minimum Variance ◽  
Moving Object ◽  
Interacting Multiple Model ◽  
Multiple Model ◽  
Object State ◽  
Motion Models ◽  
Nonlinear Motion ◽  
Tracking Process ◽  
Feature Based ◽  
Object Features

The nonlinear motion state of object seriously affects the object tracking characteristics in complex motion scene. In this paper, we propose an interacting multiple model LK (IMM-LK) tracking algorithm to enhance the performance of tracking nonlinear moving object. LK tracking approach is based on the localized gradient obtaining stable optical-flow feature, based on LK, we build several motion models of the tracked object that interact with each other in the tracking process. The method extracts different model's object features, estimates the object state and calculates the matching rate of each model with the current motion model using theory of minimum variance. Combining with the optimal transfer matrix then we can track the nonlinear moving object. The proposed IMM-LK algorithm performs favorably against conventional LK tracking on the performance of tracking nonlinear moving object.

Examining sub-daily tornado warning performance and associated environmental characteristics

2021 ◽  
Author(s):  
Makenzie J. Krocak ◽  
Matthew D. Flournoy ◽  
Harold E. Brooks
Keyword(s):  
False Alarm ◽  
Probability Of Detection ◽  
Broad Sense ◽  
False Alarms ◽  
Environmental Characteristics ◽  
False Alarm Ratio ◽  
Intermediate Products ◽  
Tornado Warning ◽  
Operational Goal

AbstractIncreasing tornado warning skill in terms of the probability of detection and false alarm ratio remains an important operational goal. Although many studies have examined tornado warning performance in a broad sense, less focus has been placed on warning performance within sub-daily convective events. In this study, we use the NWS tornado verification database to examine tornado warning performance by order-of-tornado within each convective day. We combine this database with tornado reports to relate warning performance to environmental characteristics. On convective days with multiple tornadoes, the first tornado is warned significantly less often than the middle and last tornadoes. More favorable kinematic environmental characteristics, like increasing 0–1-km shear and storm-relative helicity, are associated with better warning performance related to the first tornado of the convective day. Thermodynamic and composite parameters are less correlated to warning performance. During tornadic events, over half of false alarms occur after the last tornado of the day decays, and false alarms are twice as likely to be issued during this time than before the first tornado forms. These results indicate that forecasters may be better “primed” (or more prepared) to issue warnings on middle and last tornadoes of the day, and must overcome a higher threshold to warn on the first tornado of the day. To overcome this challenge, using kinematic environmental characteristics and intermediate products on the watch-to-warning scale may help.

An Adaptive PID Controller Based on Bayesian Theory

2017 ◽  
Author(s):  
S. Andrew Gadsden
Keyword(s):  
Pid Controller ◽  
Tracking Error ◽  
Bayesian Theory ◽  
Operating Conditions ◽  
Interacting Multiple Model ◽  
Multiple Model ◽  
Likelihood Functions ◽  
Control Gain ◽  
Adaptive Control Strategy ◽  
Future Work

One of the most popular trajectory-tracking controllers used in industry is the PID controller. The PID controller utilizes three types of gains and the tracking error in order to provide a control gain to a system. The PID gains may be tuned manually or using a number of different techniques. Under most operating conditions, only one set of PID gains are used. However, techniques exist to compensate for dynamic systems such as gain scheduling or basic time-varying functions. In this paper, an adaptive PID controller is presented based on Bayesian theory. The interacting multiple model (IMM) method, which utilizes Bayes’ theorem and likelihood functions, is implemented on the PID controller to present an adaptive control strategy. The strategy is applied to a simulated electromechanical system, and the results of the proposed controller are compared with the standard PID method. Future work is also considered.

scholarly journals Verification of Tropical Cyclone Genesis Forecasts from Global Numerical Models: Comparisons between the North Atlantic and Eastern North Pacific Basins

2016 ◽  
Vol 31 (3) ◽  
pp. 947-955 ◽  
Author(s):  
Daniel J. Halperin ◽  
Henry E. Fuelberg ◽  
Robert E. Hart ◽  
Joshua H. Cossuth
Keyword(s):  
Tropical Cyclone ◽  
False Alarm ◽  
North Atlantic ◽  
North Pacific ◽  
Probability Of Detection ◽  
Early Years ◽  
Global Models ◽  
False Alarm Ratio ◽  
The North ◽  
The North Atlantic

Abstract Accurately forecasting tropical cyclone (TC) genesis is an important operational need, especially since the National Hurricane Center’s Tropical Weather Outlook product has been extended from 2 to 5 days. A previous study by the coauthors verified North Atlantic TC genesis forecasts from five global models out to 4 days during 2004–11. This study expands on the previous research by 1) verifying TC genesis forecasts over both the Atlantic and eastern North Pacific basins, 2) extending the forecast window to 5 days, and 3) updating the analysis period through 2014. Verification statistics are presented and compared between the two basins. Probability of detection and critical success indices generally are greater over the eastern North Pacific basin compared to the North Atlantic. There is a trade-off between models that exhibit a greater probability of detection and a greater false alarm ratio, and models that exhibit a smaller false alarm ratio and a smaller probability of detection. Results also reveal that the models preferentially miss TCs over the North Atlantic (eastern North Pacific) that have a relatively small radius of the outer closed isobar (radius of maximum wind) at the forecast genesis time. Overall, global models have become a more reliable source of TC genesis guidance during the past few years compared to the early years in the dataset.

scholarly journals Characteristics of Tornado Events and Warnings in the Southeastern United States

2019 ◽  
Vol 34 (4) ◽  
pp. 1017-1034 ◽  
Author(s):  
Alexandra K. Anderson-Frey ◽  
Yvette P. Richardson ◽  
Andrew R. Dean ◽  
Richard L. Thompson ◽  
Bryan T. Smith
Keyword(s):  
United States ◽  
False Alarm ◽  
Southeastern United States ◽  
Probability Of Detection ◽  
High Shear ◽  
Related Literature ◽  
False Alarm Ratio ◽  
Tornado Warnings ◽  
Tornado Warning

Abstract The southeastern United States has become a prime area of focus in tornado-related literature due, in part, to the abundance of tornadoes occurring in high-shear low-CAPE (HSLC) environments. Through this analysis of 4133 tornado events and 16 429 tornado warnings in the southeastern United States, we find that tornadoes in the Southeast do indeed have, on average, higher shear and lower CAPE than tornadoes elsewhere in the contiguous United States (CONUS). We also examine tornado warning skill in the form of probability of detection (POD; percent of tornadoes receiving warning prior to tornado occurrence) and false alarm ratio (FAR; percent of tornado warnings for which no corresponding tornado is detected), and find that, on average, POD is better and FAR is worse for tornadoes in the Southeast than for the CONUS as a whole. These measures of warning skill remain consistent even when we consider only HSLC tornadoes. The Southeast also has nearly double the CONUS percentage of deadly tornadoes, with the highest percentage of these deadly tornadoes occurring during the spring, the winter, and around local sunset. On average, however, the tornadoes with the lowest POD also tend to be those that are weakest and least likely to be deadly; for the most part, the most dangerous storms are indeed being successfully warned.

scholarly journals PERBANDINGAN TEKNIK WARM DAN COLD START PADA MODEL WRF-3DVAR ASIMILASI DATA RADAR PADA PREDIKSI HUJAN LEBAT DI WILAYAH SURABAYA DAN SEKITARNYA

2020 ◽  
Vol 21 (1) ◽  
pp. 13-21
Author(s):  
Nayla Alvina Rahma ◽  
Jaka Anugrah Ivanda Paski
Keyword(s):  
False Alarm ◽  
Cold Start ◽  
Probability Of Detection ◽  
False Alarm Ratio ◽  
Warm Start ◽  
Constant Altitude ◽  
Position Indicator

Penelitian ini bertujuan untuk mengetahui perbedaan hasil prediksi hujan WRF-3DVAR asimilasi data radar dengan menggunakan teknik warm start (spin-up 12 jam) dan cold start (tanpa spin-up). Kejadian hujan yang dianalisis adalah kejadian hujan lebat tanggal 19-20 Januari 2019 di wilayah Surabaya dan sekitarnya. Data yang digunakan untuk simulasi adalah data Global Forescast System (GFS) dan data reflektivitas radar cuaca BMKG Surabaya produk Constant Altitude Plan Position Indicator (CAPPI). Analisis dilakukan dengan membandingan kondisi awal model pada parameter suhu dan kelembaban udara untuk mengetahui efek dari metode asimilasi data. Uji keandalan model dilakukan dengan melakukan verifikasi dikotomi (hujan/tidak hujan) hasil luaran model WRF dengan data hujan di 4 titik pengamatan, yaitu di Stasiun meteorologi Juanda, Stasiun meteorologi Perak, Stasiun Klimatologi Karangploso, dan Stasiun Geofisika Tretes. Hasil menunjukkan bahwa asimilasi data radar dengan mode cold start mempunyai hasil yang lebih baik dibandingkan dengan warm start, yang ditandai dengan lebih tingginya nilai Probability of Detection (POD) dan lebih rendahnya False Alarm Ratio (FAR). Asimilasi data dengan menggunakan mode cold start memiliki performa yang lebih baik dalam mendeteksi curah hujan per jam dengan ambang batas >1 mm dan >5 mm, sedangkan curah hujan >10 mm per jam lebih baik diprediksi menggunakan mode warm start.

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