Google began Wednesday letting businesses target mobile ads based on how close smartphone users might be to shops or what they might be craving at certain times of day.

Google began upgrading its AdWords service with "enhanced campaigns" for advertisers trying to better connect with people accessing the Internet on the move with smartphones or tablet computers."People are constantly connected and moving from one device to another to communicate, shop and stay entertained," Google senior vice president of engineering Sridhar Ramaswamy said in a blog post."Enhanced campaigns help you reach people with the right ads, based on their context like location, time of day and device type."For example, a breakfast cafe interested in reaching people searching for "coffee" on smartphones could arrange to bid higher for people within close distance and less for queries made after noon.

AdWords uses a bidding process to determine which advertisements are posted along with results for specified query terms. Modern smartphones and tablets are built with location-sensing technology that users can activate.Ads shown to smartphone users could be customized with one-touch calling options or map directions, while the same merchant would provide a shopping website link to people browsing online from a desktop computer.AdWords also lets merchants track how often ads lead to telephone calls.The upgrade comes as modern lifestyles increasingly revolve around staying connected to the Internet with smartphones or tablet computers.