Thread: Humminbird GPS In-Depth...

I learned a little more today...

I just got off the phone with some GPS Specialist that I know. One being the Resident GPS Expert at Humminbird to get the answers which you requested and end without a shadow of any doubt why I can track 17 Satellites with my Humminbird GR-50 Receiver.

All 3 Experts I talked with explained the US GPS Constellation is not symmetrical or spaced equally. Some satellites are in clusters or small groups, as you can see in the image below but still all help in locating position. They also stated that the advertised constellation is 24 satellites but right now there are from 31-32 active satellites in orbit that can be used to calculate your position. So Yes you can track over 12 satellites at certain periods of time in the current consumer US Constellation.

The reason for clusters or groups of satellites is because older satellites are being upgraded with new satellites and both the old and new satellites are both functioning at present time with accurate data to help in locating your position. They also stated that there are actually 3 WAAS Satellites orbiting right now. 2 (like advertised) are maintaining the intended track and a 3rd is in and out of service but can be displayed and provide position location as it becomes in service.

With consumer electronics the maximum allowable displayed trackable satellites are 18 but more can be tracked that are coming above the horizon or falling off the horizon but not displayed. If you look at the image below the light gray satellites are being tracked but the data is not being used at the present time to help establish position because they are outside the useable threshold Humminbird uses to help locate position. Other words until they reach a threshold that will help improve the accuracy that data is not figured in to calculate location but still being represented and tracked. When they reach that level they can add benefit to locating position then they will be represented in black.



The benefit to being able to track additional satellites is to increases the response to acquire position and it allows the GPS to maintain a higher level of accuracy as it can start tracking a satellite earlier as it rises above the horizon and hold on to it longer before it leaves the horizon. Having open channels allows for improved GPS performance.

I also was informed the Current Galileo Project by the European Union is not being used and only 2 Satellites are currently orbiting earth and the accurate track of these satellites are not valuable yet to improve GPS in locating your position. Glonass Project maintained by Russia is orbiting and can become available for civilian use in the near future but as of date none of the Glonass Constellation is being used in position location for Humminbird.

The Standard GPS Receiver from Humminbird is not only providing more as standard equipment but is prepared for expansion when new opportunities arise as more and more Position Satellites are added to the current Constellations and the use of other Constellations become developed.

Hope this helps you learn more about how your Humminbird GPS Performs.

Dear Tom,


Thank you for contacting Garmin Marine Support.


There is no advantage to having more satellites, all that is needed is 4 satellites to connect to get 3-D GPS tracking.


Thank you for contacting Garmin and have a nice weekend.


Sincerely,


James Frazier