Mr Newton-Price finishes his questioning. Mr Mousley calls an expert witness, a professor with 50 years of experience in navigation systems and 26 years in GPS navigation.
The professor tells the court about GPS. He says it is a navigation and positioning system, operated by the US government.
He says it involves 32 satellites, of which at any point on the surface of the planet, a person is visible by around nine of those.
He tells a court that a phone acts as a GPS receiver, collecting a signal from those satellites. He says there is a "remarkable" calculations made, which can then mark that device's position.
He says the Global Navigation Satellite System (GNSS) can be disrupted by tall buildings in cities, as well as being in someone's pocket or a wooded area. He adds that if there are issues with the GNSS, the phone's location could also be found using Wifi Positioning and Cell Sighting.
The expert says that he agrees with the defence's "scepticism" over the Google Fitness App data.
But he describes Hampshire Constabulary's use of cloud data in the Lucy McHugh investigation as "groundbreaking" and "very exciting".
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