What is the accuracy of the axiom 7 internal gps with the axiom unit mounted on the console (not IN but on top of, without any obstruction from the sky) vs. an external gps antenna? What performance improvements might I expect with such an external antennae? (I need to be exactly on certain GPS coordinates for structure and fishing locations). Thanks
Welcome back to the Raymarine Forum Greg,
Q. What is the accuracy of the axiom 7 internal gps with the axiom unit mounted on the console (not IN but on top of, without any obstruction from the sky) vs. an external gps antenna?
A. The material which the mounting surface has been constructed from, as well as other electronics which have been installed within the mounting surface will all factor into the strength of the GPS signal received by the MFD's internal GPS receiver. For most installations, these are negligible. Accuracy is reported within the LightHouse 3 Satellites dialog and will be expressed in feet as well as an HDOP value. An unobstructed MFD's internal GPS receiver will typically be able to produce an HDOP of 1.0 or less (a lower number is better) and an accuracy of 8' or less. As indicated within the FAQ found
here, should a higher HDOP value be reported by the system, then you may want to consider interfacing an external GPS sensor to the system.