Amazon is planning to build giant towers full of products ready to be shipped to customers by autonomous drones.

A patent application filed by the e-commerce giant reveals how the towers, potentially some eight stories tall, would be stocked up by delivery truck. Order placed by local customers will then be packaged up, fitted to a drone and sent to their garden. Here, using techniques already demonstrated by Amazon, the package will be dropped off and the drone then returns to the fulfilment tower recharge and restock.

Amazon outlines problems with today's fulfilment centres, stating they "are typically large-volume single-floor warehouse buildings used to temporarily store items prior to shipment to customers.

"Often, due to their large footprint, these buildings are located on the outskirts of cities where space is available to accommodate these large buildings. These locations are not convenience for deliveries into cities where an ever-increasing number of people live."

This, Amazon says, has led to the "growing need and desire to locate fulfilment centres within cities, such as in downtown districts and densely populated parts of the cities". The patent was published on 22 June by the US Patent and Trademark Office.

Amazon has been working hard on making drone deliveries a reality for several years, and in December 2016 began a limited service, called Prime Air, in rural Cambridgeshire. The drones, which fly at an altitude of 400ft (120m) and are guided by GPS, can carry packages weighing up to five pounds (2.25kg); Amazon says this accounts for the majority of orders placed by customers. Orders arrive in less than 30 minutes. An Amazon video shows a package arriving 13 minutes after the order was placed.

Amazon drone delivery centre
Amazon Patent explains how warehouse towers would supply city centre delivery dronesAmazon via US Patent & Trademark office

In May this year, an Amazon patent revealed how the company is working on ways to parachute deliveries from drones into a customer's garden, negating the need to land and takeover, which takes time and uses up precious battery power.

Amazon still faces many regulatory hurdles before it can turn its Prime Air trial into a real-world service, but the regular updates and constant progress - as well as some slick marketing videos - show the company is confident about making drone deliveries a reality.