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Where Am I?

Humans have long been seeking answers to the question of "Where am I?" From early navigators to modern day users of GPS equipment, science has played a role in answering this question. This quest has many connections to the work at the Haystack Observatory: from celestial observations, to space weather effects on GPS, and VBLI studies of geodesy and the motions of the Earth's plates.

All of these are based on the propagation of electromagnetic waves and their interference.

Global Positioning System (GPS)

GPS relies heavily on the very precise timing of how long it takes for radio transmissions from satellites to travel to your GPS receiver. This timing is very dependent on the accuracy of the clocks on the satellites and receivers, the state of the atmosphere, and activity in the ionosphere. The exploration of GPS can include mapping projects, the study of electromagnetic wave propagation, and the analysis of the ionosphere (as performed by the Millstone Radar.)

Go to the GPS Page for links explaining how GPS works and a lesson plan that explores the operations of GPS units and their relationship to work that is being performed at Haystack.

(More can be learned about the ionosphere and the Millstone Radar at our Atmospheric Science Page.)

For more background information on location and GPS check out the NOVA-Online presentation Lost at Sea: The Search for Longitude. This site includes several Shockwave demonstrations that explain the difficulties in determining longitude as well provide an visual presentation about how GPS works. A Teacher's Guide is also presented as part of the NOVA site.

You may also read The Passage of Time for a brief history of man's attempts to tell time.

Very Long Baseline Interferometry (VLBI)

VLBI is a technique where several different radio telescopes can be combined to perform as if they were one, much larger, radio telescope. This technique allows for mapping of the universe with greater resolution and determining the positions on the Earth's plates with great accuracy. Look here in the future for lesson plans that will help you explore VLBI in your classroom!
18 January 2000