@ Bushwalker8,

Please do not confuse the GPSMAP 66s/st or your GPSMAP 66i capabilities with the GPSMAP 66sr. As you stated, your GPSMAP 66i 'Multi-GNSS' only uses GPS + Galileo. This is still an advantage, as twice as many SV's are always better. But these devices only use the L1 Band.

The GPSMAP 66sr (and GPSMAP 65) 'Multi-GNSS' capabilities include using FIVE GNSS constellations simultaneously. Those are GPS + GLONASS + Galileo + NavIC + QZSS. Further, these devices use both Li and L5 bands for GPS and Galileo (GLONASS does not support additinoal bands for civilian use). This allows for real time atmospheric correction and multi-path rejection. It is my understanding that these devices do not support WAAS or EGNOS because their own on-board corrections provide better results.

The 66sr also supports RINEX logging, so you may want to investigate further the capabilities of a true 'Multi-GNSS' + 'Multi-Band' receiver!

Quote Originally Posted by Bushwalker8 View Post

And if you really think the device only needs 4 or 5 satellites for a fix there is a serious disconnect with the accuracy discussion, you may want to play with the charts here to understand the relationship between the number of satellites and DOP: [Only registered and activated users can see links. ]
Apples and Oranges.

We both know that three satellite signals provides the receiver with two possible location solutions when using a fourth satellite clock signal exclusively for the purpose of synchronizing the other signals. In this scenario, one solution is usually very near the Earths surface while the other is either far below or high above the Earths surface, and the GPSr can 'guess' the position near the surface is the correct location. Adding one more satellite signal (total of five now) allows the receiver to verify which of the two previous solutions is the true location, and 'guessing' is no longer necessary.

I never suggested that accuracy would not improve when more than five satellite signals were available.

And I never suggested the Garmin consumer grade devices would provide accuracy identical to survey grade equipment.

However, the new Garmin 'Multi-Band' devices are a significant step forward in consumer grade satellite positioning technology.