All known GPS speedometers use an external GPS antenna when in communication with a GPS. However, there are many problems with using an external GPS antenna. It is often difficult and sensitive to route the antenna wiring throughout the vessel or vehicle, as well as the susceptibility of this antenna to damage from exposure to the environment. An external GPS antenna and the associated wiring require expensive environmentally sealed and resistant coatings and materials, plus the basic costs of a separate enclosure unit of the antenna itself increase the costs of such a speedometer system. Additional costs and complexity rise since the external antenna requires an internal battery (power source) to retain location information for quick TTFF (Time To First Fix) as typically required of a GPS. When this battery ultimately dies, approximately 3 years after installation, the external antenna ceases to provide quick TTFF.
Currently, all GPS speedometer indication instruments (gauge type indicators) require external antennas for acquiring a GPS signal.
Thus there is a need for a GPS speedometer that overcomes the above listed and other disadvantages.