مدل‌های پیش‌بینی داپلر اتمسفری در گیرنده GPS-RO برای ردگیری حلقه‌باز

نوع مقاله: مقالة‌ تحقیقی‌ (پژوهشی‌)

نویسندگان

1 پژوهشکدة ارتباطات و فناوری اطلاعات، پژوهشگاه ارتباطات و فناوری اطلاعات

2 پژوهشکدة برق و فناوری اطلاعات، سازمان پژوهشهای علمی و صنعتی ایران

چکیده

در این مقاله، ابتدا نهفتگی رادیویی و اهمیت ردگیری سیگنال برای گیرنده‌های GPS-RO شرح داده می‌شود. سپس ردگیری حلقه‌باز به عنوان ابزار توانمند و جایگزین ردگیری‌ حلقه‌بسته، برای دریافت سیگنال‌های متفرقشده GPS، گذرنده از تروپوسفر پایین، معرفی می‌شود. ‌در تحقق ردگیری حلقه‌باز با نرخ پایین، اهمیت مدل‌ داپلر مطرح می‌شود. در این مقاله به سه روش مهم در پیاده سازی مدل داپلر اتمسفری که هم اکنون عملیاتی شده‌اند، پرداخته می‌شود. ابتدا روش سوکولوفسکی، که از روش‌های اولیه و مهم بوده و در گیرنده ROSA به کار می‌رود، تبیین می‌شود. سپس روش سی. اُ. آو که در گیرنده مهم BlackJack تعبیه شده است، مطرح شده و در ادامه روش کریستنسن بیان می‌شود که در گیرنده GRAS عملیاتی شده است. نحوه اعمال ورودی‌های هندسی و اتمسفری در این روش‌ها و دقت آنها بررسی خواهد شد. سپس با بهره‌گیری از دانش به‌دست آمده از نقاط قوت و ضعفاین مدل‌ها، یک مدل ترکیبی برای گیرنده GPS-RO ایرانی به همراه الگوریتم پیاده‌سازی آن مطرح می‌گردد.
 

کلیدواژه‌ها


عنوان مقاله [English]

Atmospheric Doppler Modelling for Open Loop Tracking in GPS-RO Receivers

نویسندگان [English]

  • L. Mohammadi 1
  • Sh. Amiri 2
  • Gh. Mohammadkhani 2
1 Department of Institute for Communication Technology, ICT Research Institute
2 Department of Institute of Electrical and Information Technology, Iranian Research Organization for Science and Technology (IROST)
چکیده [English]

One of the main challenges of the Open-Loop Signal Tracking method in GPS-RO space receivers, is Doppler prediction. Almost in all satellite communication systems, accurate carrier phase tracking under difficult conditions is depend on Doppler prediction accuracy. Obviously, there are several methods for producing a predicted Doppler model, and one of the earliest is Sokolovskiy. In this paper, we are analyzing the typical and operational atmospheric Doppler prediction models for the Open-Loop Signal Tracking of radio occultation, in satellite communications. A summary and comparison between these methods will be concluded in the end of this paper. finally we propose a prediction method can be used in national GPS-RO payloads for predicting atmospheric doppler based on combination of Sokolovsky and C.O. Ao methods.
 

کلیدواژه‌ها [English]

  • Radio occultation
  • Open loop tracking
  • Atmospheric doppler

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