Solix Internal GPS Accuracy Question

[bobcoy]

Sly, I was looking at the HDOP numbers. The internal is better on some. Bob

[bobcoy]

I have not looked at the strength screen in some time, but I know my external(GPS HS) showed the Glonass birds. I will try to get out tomorrow morning if I can (gonna be 95 so it will have to be early) to make sure I can still see GLONASS. Might be a bug. I still have not loaded the latest in my Solix G1. Bob

[bobcoy]

Over 80 at 9 am. Maybe tomorrow. I hope someone with a G2 and hs takes a look at their GPS screen, that should let you know if your hs is good or not. Bob

[SLYDoggie]

Over 80 at 9 am. Maybe tomorrow. I hope someone with a G2 and hs takes a look at their GPS screen, that should let you know if your hs is good or not. Bob

Hey there Bob. I did some additional testing with today comparing the Solix Internal GPS with the external AS GPS HS. I had never paid any attention to the HDOP ratings and you are exactly right. Although the Solix internal GPS has lower signal strength from the satellites, the HDOP numbers are consistently lower than the AS GPS HS. This morning while I was out trolling, the Solix internal GPS ranged from .59 to .81 while the AS GPS HS ranged from .82 to 1.05. Every time I checked it, the Solix Internal GPS was around .2 better than the AS GPS HS.

These were all with the GLONASS turned on although it has no impact on the AS GPS HS.

[Mike2718]

Hey there Bob. I did some additional testing with today comparing the Solix Internal GPS with the external AS GPS HS. I had never paid any attention to the HDOP ratings and you are exactly right. Although the Solix internal GPS has lower signal strength from the satellites, the HDOP numbers are consistently lower than the AS GPS HS. This morning while I was out trolling, the Solix internal GPS ranged from .59 to .81 while the AS GPS HS ranged from .82 to 1.05. Every time I checked it, the Solix Internal GPS was around .2 better than the AS GPS HS.

These were all with the GLONASS turned on although it has no impact on the AS GPS HS.

You can't get "too caught up" in the HDOP. It is NOT a measure of distance. It is a mathematical equation based on different factors to ESTIMATE the degree of precision. The "true" measure of the accuracy is to mark a waypoint that you can go back to that exact location without having to use a gps, then "tell" your unit to take you to that spot and see how close it will get you to it. I have mentioned before that I have a handheld gps unit that is 23 or 24 years old that will take me back to the very 1st waypoint on that unit within a couple of feet almost every single time. When the government stopped "scrambling" the signal back in the 90s, that helped the accuracy more than anything. You have to remember every gps unit receives the EXACT same information from all the satellites. You can have a very low HDOP but have a weak signal or be in an obstructed area that affects your signal and your unit could potentially be "way off." I have found all my gps units to be accurate within 3' almost every time. The point is that gps units are extremely accurate.

[bobcoy]

HDOP is a number that can tell you if you have a good fix or not. .2 difference is not a big deal but if it is close to 1(+or-) I have learned to rely on a good fix. If I don't get close to 1 I am looking for a reason(blockage of some kind) WAAS enters into the equation, but I don't know if it is counted within the HDOP equation or not. I don't want to do the calculations so I rely on HDOP to tell me good or not so good.

[electritek]

This thread has blown me away with technology. Thank you all very much!