Multiplexing GPS signals from two separate receivers?

psyklik · Occasional Visitor Joined: May 12, 2006 Posts: 5

What is the result of multiplexing GPS signals from two separate receivers, one w/ DGPS the other w/ WAAS? Question

~ psyklik

philpugh · Posted: Wed Oct 15, 2008 10:13 am Post subject:

How do you mean 'multiplexing'?

If they are both receivers then both will be providing a calculated fix - which will possibly be different. I don't see how most commercial applications would use this as they expect input from only one receiver. If it's a true DGPS receiver, that is receiving DGPS correction information from an external source (e.g. radio or Internet), then I would just stick with that as it should be more accurate.

If, however, you have a GPS receiver (WAAS or not) capable of using DGPS info AND a DGPS signal (i.e. the correction information - NOT the calculated position) then you "simply" plug it in and get more accurate information from the receiver.

If I misunderstood your question - I apologise - but if you could explain what you are trying to acheive then I'm sure the people here can help.

If you are consistently getting WAAS signals then your receiver will be more than accurate enough for consumer applications.
_________________
Phil

psyklik · Occasional Visitor Joined: May 12, 2006 Posts: 5

Phil,

In my case there are two separate GPS receivers aboard, a Garmin 76cx (WAAS), and a Garmin 230 Chartplotter receiving correction from a Raytheon D-Beacon RX. The 230 feeds my instrument system (as you recommend). I was just curious if anything could be gained from the WAAS side of the house?

Regards, Rich

philpugh · Posted: Wed Oct 15, 2008 5:43 pm Post subject:

Ok - that explains the two receivers!

I guess from an academic point of view it could be interesting to see the differences between the WAAS and DGPS systems. Does the Chart Plotter do tracklogs? It would make it simpler just comparing a list of points with Excel or similar.

Where do you sail and do you get good periods of WAAS reception?

Walking (and occasional sailing) in North UK doesn't lend itself to good WAAS reception unfortunately.
_________________
Phil

psyklik · Occasional Visitor Joined: May 12, 2006 Posts: 5

Phil,

Comparing the two track files sounds like a good project for next sailing season.

Our homeport is Noank. We sail priimarily on Eastern Long Island Sound, Fishers Island Sound and Block Island Sound primarily. Our local DGPS transmitter is approximately 50 nm to the southwest at Moriches, LI, NY.

Thanks for the feedback,

Rich

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