In Global Navigation Satellite System (GNSS) positioning. observation precisions are frequently impacted by the site-specific unmodeled errors. especially for the code observations that are widely used by smart phones and vehicles in urban environments. The site-specific unmodeled errors mainly refer to the multipath and other space loss caused by the signal propagation (e. https://www.trendingcustomes.shop/product-category/multi-charm-wooden-keychain/