What does it do? 

ke_search_premium is a TYPO3 extension which extends ke_search with a number of additional features:

• Custom ranking: values to push results by a fixed value
• Boost keywords: push results by keywords
• Distance based: Search around a location (city, zip), including Google Maps integration
• Did you mean: Suggest correct spellings (only in german)
• Autocomplete: Suggest search terms while typing (based on searches of other users)
• Synonyms: Define synonyms for search terms
• In-word-search: Find search strings inside words
• Remote indexer: Import search results from another TYPO3 website. This feature makes it possible to search two or more TYPO3 websites using one search form.
• Headless: Serve search results via JSON, e.g. for a Progressive Web App
• Sphinx: Faster searching (with very large indexes) with Sphinx (needs additional server setup)