What is pilot survey? What are its advantages?

Follow the given link to know the meaning of pilot surveys.

https://www.meritnation.com/ask-answer/question/define-pilot-survey/academics/5898810

Follow the given link to know the advantages of pilot surveys.

https://www.meritnation.com/ask-answer/question/what-are-the-advantages-of-pilot-survey/economics/8998367