نوع مقاله : یادداشت تحقیقاتی

نویسندگان

1 دانشجوی دکتری، پژوهشگاه فضایی ایران، تهران، ایران .

2 دانش آموخته دکتری، پژوهشگاه فضایی ایران، تهران، ایران

3 استادیار، پژوهشگاه فضایی ایران، تهران، ایران

چکیده

خطای ناوبری در کاربرد رادار با دهانة مصنوعی (سار) منجر به خطای فاز سیگنال بازگشتی و کاهش کیفیت تصویر سار می‌شود. از این میان، خطای فاز مرتبه‌های صفر و یک بر کیفیت تصویر اثری ندارد، اما خطای فاز مرتبه‌های دوم و بالاتر بسیار حائز اهمیت است. بخش عمدة خطای فاز مرتبه‌های دوم و بالاتر ناشی از خطاهای زاویة اولیه، بایاس سنسورهای اینرسی و رفتار تصادفی این سنسورها است. به منظور فائق آمدن بر این مشکل از سیستم‌های ناوبری تلفیقی INS/GPS استفاده می‌شود. از طرفی، وجود گسستگی در خروجی سیستم‌های ناوبری تلفیقی منجر به کاهش شدید کیفیت تصویر سار می‌شود. در این مقاله، اثر رویکردهای مختلف بخش ناوبری بر پاسخ ضربة سمت مورد بررسی قرار گرفته و اهمیت استفاده از الگوریتم‌های ویژه برای تلفیق داده‌های INS و GPS نشان داده شده است. سپس، با توجه به رفتار خطای ناوبری، الگوریتم پیشنهادی برای ناوبری در سار ارائه شده و مزیت آن در پاسخ ضربه سمت و کیفیت تصویربرداری به نمایش در آمده است.

کلیدواژه‌ها

عنوان مقاله [English]

Challenges of Inertial and Integrated Navigation Systems in Synthetic Aperture Radar Application

نویسندگان [English]

  • Vahid Cheraghi Mahmudabadi 1
  • Hadi Makarem 2
  • Majid Hatam 3

1 Ph.D. Student. Iranian Space Research Center. Tehran.Iran .

2 Ph.D. Iranian Space Research Center. Tehran.Iran .

3 Assistant Professor .Iranian Space Research Center. Tehran.Iran

چکیده [English]

Navigation errors in synthetic aperture radar (SAR) applications lead to phase errors in SAR echo signal and image quality degradation. Among different phase errors, zero and first order errors have no effect on image quality, while second and higher order terms are very important. The majority of second and higher order phase errors are due to initial alignment errors, and bias and random errors of inertial sensors. Integrated INS/GPS navigation systems are used for solving this problem. However, discontinuities in integrated navigation data lead to severe SAR image quality degradation. In this paper, the effect of different navigation approaches on SAR azimuth impulse response was studied and the importance of specially-designed algorithms to integrate INS and GPS was illustrated. Then, the proposed algorithm for navigation in SAR application was presented according to navigation errors behavior, and its benefit in azimuth impulse response, and imaging quality was illustrated. ‌‌

کلیدواژه‌ها [English]

  • Synthetic Aperture Radar
  • Inertial Navigation System
  • Integrated Navigation System
  • Azimuth Impulse Response
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