Is my Sat Nav broken? -- Royal Observatory, Greenwich, London, UK
N 51° 28.673 W 000° 00.088
30U E 708215 N 5707233
One of five historical markers around the Prime Meridian in the garden of the Royal Observatory at Greenwich
Waymark Code: WMT42A
Location: London, United Kingdom
Date Posted: 09/21/2016
Views: 4
Five interpretive signs discussing the history and significance of invisible lines on the Earth are arranged neatly perpendicular to the Prime Meridian. This sign, the fifth of five, explains why your GPS/Sat Nav does not read 0 00.000 at the Prime Meridian.
The sign reads as follows:
"IS MY SAT NAV BROKEN?
Does your Sat Nav tell you that you are standing at precisely longitude 0°?
The current system used for satellite navigation and phones and other devices takes into account later data on the Earth’s slightly irregular shape. Because of this, there is a small difference between the Prime Meridian and the satellite meridian: the latter is about 100m further east.
Angles are measured in degrees, which are divided into smaller units called arc minutes and arc seconds. When you stand on the line your east-west position as longitude 0° 0’ 0”.
To find out more please visit [web address]"
Type of Historic Marker: Interpretive sign
Historical Marker Issuing Authority: Royal Museums Greenwich
Age/Event Date: 01/01/1984
Related Website: [Web Link]
Give your Rating: 
|
Visit Instructions:
Please submit your visiting log with a picture of the object and include some interesting information about your visit.