استخراج سطوح بهینه مدولاسیون عرض پالس در فرستنده سوئیچینگ لورن جهت سامانه موقعیت‌یاب زمین‌پایه

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشگاه صنعتی مالک اشتر

2 دانشگاه جامع امام حسن (ع)

3 دانشگاه جامع امام حسین (ع)

چکیده

یکی از مهم‌ترین بخش‌های سامانه لورن، مولد سیگنال ارسالی است که نقش آن تولید پالس‌های با توان بالا و شکل موج استاندارد است و برای ساخت آن روش‌های متعددی وجود دارد. یکی از این روش­ها استفاده از تقویت­کننده­های سوئیچنگ مبتنی بر مدولاسیون عرض پالس(PWM) است. در این مقاله اصلاح ‌تقویت‌کننده‌های PWM ساده به تقویت‌کننده‌های PWM چندسطحی (با تعداد سطوح بهینه) جهت به‌کارگیری در فرستنده‌های لورن مورد توجه است. به همین‌ منظور برای ایجاد توان MW1 از سه تا یازده سطحPWM  با استفاده از 16 بلوک تقویت­کننده کلاس D با ثابت نگه‌داشتن تعداد المان‌های قدرت و در نظر گرفتن شرایط و ملاحظات پیاده‌سازی سخت‌افزاری شبیه‌سازی شده است. بر اساس نتایج شبیه­سازی­ها در بهترین حالت (11 سطحی) حداکثر خطای عبور از صفر در نیم سیکل چهارم تا دوازدهم ns6/16و پهنای باند آن kHz5 است. همچنین MMSE و حداکثر خطای نقاط اوج در هشت نیم سیکل اوّل
به ترتیب 009/0 و 0221/0 است که استانداردهای موردنیاز را تأمین می­کند.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Extraction of Optimum PWM Levels in LORAN Switching Transmitter for Ground-Based Positioning System

نویسندگان [English]

  • A. Khorrami 1
  • A. Afifi 1
  • M. H. Ghezel Ayagh 2
  • A. Amin 3
1 Malek Ashtar University of Technology
2 emam hossein university
3 Imam Hossein University
چکیده [English]

Long-Range-Navigation (LORAN) pulse generator is an essential part of ground-based Local Positioning System (LPS) that provide a specific standard waveform. There are several solutions for design and implementation of the pulse generator. Switching amplifiers using Pulse-Width-Modulation (PWM) technique is one of the solutions that can be used for this purpose. In this paper, the simple PWMwas modified to a multi-level PWM and its optimum levels are extracted to provide a high power LORAN transmitter.  Multi-level PWM provides essential standards of LORAN pulse waveform. In order to provide a transmitter with 1MW power, three- to- eleven levels of PWM using 16 Class D amplifiers has been considered. At constant conditions, such as power and number of amplifier modules, the requirements and specifications of transmitter have been simulated. Simulation results show that in the best case, using eleven levels for PWM,the maximum zero crossing error in the 4th to 12th half-cycle is 16.6 ns and the bandwidth of provided pulse is 5 kHz. Moreover, MMSE and maximum error of peak points in the first eight half-cycles are 0.009 and 0.021 respectively, which are appropriate standards of a LORAN transmitter.

کلیدواژه‌ها [English]

  • Local Positioning System (LPS)
  • Multi-level PWM
  • LORAN Signal
  • Navigation
  • Class-D Amplifier
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