Details about how Amazon's proposed delivery drones may work have been published by the US Patent Office.

According to the patent, the drones will be able to track the location of the person it is delivering to by pulling data from their smartphone.

The unmanned vehicles will also be able to talk to each other about weather and traffic conditions.

Amazon faces many regulatory hurdles before its plans can be turned into reality.

Amazon submitted its drone patent in September 2014, but the details are only now being published by the US Patent and Trademark Office, after it approved the ideas.

For many, Amazon's idea of delivery via drone was seen as pie-in-the-sky, but the details it provides in its patent application suggest that the firm is taking the idea seriously and working hard to overcome a variety of technical obstacles.

Winning patent approval does not mean that the final product will be exactly as described or that it will become reality.

Amazon is leading the effort to convince the US Federal Aviation Authority (FAA) to approve widespread commercial use of drones.

According to the plans, Amazon's drones will be able to update their routes in real-time. A mock-up delivery screen suggests that people will be able to choose from a variety of delivery options - from "bring it to me" to nominating their home, place of work or even "my boat" as places for packages to be dropped.

Last month car maker Audi said that it would be trying out package delivery to the boot of its cars with Amazon and DHL.

Using Audi's in-car communications system, Connect, DHL delivery drivers would track a customer's vehicle over a specified period of time and then use a digital access code to unlock the boot, the car maker said. This code would then expire as soon as the boot was shut.

Other details revealed include:

• Amazon will employ a variety of unmanned vehicles depending on the shape and weight of the product

• Flight sensors, radar, sonar, cameras and infrared sensors will be employed to ensure safe landing zones are found

• The unmanned vehicle would constantly monitor its path for humans or other animals and modify navigation to avoid such obstacles

Significant strides

Amazon's plans for drone delivery puts increasing pressure on the FAA to allow more US-based drone research and development.

It has been criticised for dragging its heels on regulation and losing the impetus on drone development which has gone to other countries, most notably the UK which will build a drone research centre in London.

This week the FAA did make significant strides towards relaxing its rules on drone use, giving the go-ahead for unmanned helicopters to be used for spraying crops in the US as well as announcing plans for testing news-gathering drones in urban areas in partnership with CNN.

It also said it would also test commercial drones that can fly beyond an operator's line of sight for inspecting railways.

Amazon had been testing its drone system in Canada where airspace regulations are more relaxed. but in March the FAA granted it permission to start testing in the US, although the drones can fly no higher than 400ft (122m) and must remain within the pilot's line of sight.