I've noticed a discrepancy when auto posting to GPSS and from there to GPSTC using GPSResults in the distance and hour.
GPSResults had a default filter setting I had mine set to 1knt but everytime I auto sent my results it reverts back to a 5knt minimum don't know wether other GPS software is the same but it makes a big difference.
My last session I did in distance 68.92km with the filter set at 1 knt when I auto sent the data to GPSS it was recorded at 61.37km and my hour went from 19.40 to 18.97.
I uploaded the file to KA72 site and it gave me a distance of 69.26km Vando checked the file on Real Speed and it showed 69.45km.
When I'm out on the water floating around waiting for a gust doesn't this count as sailing?
Maybe we should all use the same program to upload times to GPSTC like KA72? this way if someone sails over 100km in a day they are not going to lose 10-15km out of their session if they happen to drop below a given filter setting.
Don't know wether the same happens with GPSaction replay or Real Speed when auto posting but it's food for thought.

Let Manfred know and I am sure he will fix it pronto.

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yoyo said...

Let Manfred know and I am sure he will fix it pronto.

This was Manfred's response on GPSS

"Hi Meta, this may be due to the filter settings you used. Before uploading the results the default values are used for all computations and after sending your individual settings are restored. For the distance and the hour for examples a minimum speed of 5 knots applies (minimum of 5 sats etc.), so if you have reduced some of these values in your Filter Settings you may get different results as comared to those that are sent..."

So i gather that GPSS has a minimum value of 5knts then

I think you can easy do under 5kts slogging.

I seem to remember a few months ago somebody else noticing a distance discrepancy due to min speed settings, only I think this was the other way round. Some thing about the software assuming the speed continued at the last recorded speed for the whole unrecorded period.
This led to greater distances being calculated for higher min speed settings.
I guess this is probably when using doppler.

Any body else remember this????

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choco said...

Maybe we should all use the same program to upload times to GPSTC like KA72?

KA72 has a bit to go before it could become the default, one issue I have is when I forget to trun off my gps before driving home. Maybe Dylan can add the code to detect and delete this. If not I will still ocasionally have to delete data in Realspeed before posting

As for the minimum speed I think if you are on the water then movement should count. That said 2 hours moving at 2 knots is unlikely to hugely inflate someones distance travelled (unless they did nothing else). I will check some of my posts against KA72 to see how they compare.

I also use GPSR but when i want to see distance filter must be OFF
(also that happens with 1 hour)
For all other parameters filter is ON
Try it and check with KA72

also my filter looks like:
minimum speed: 3KT
max acce: 3msec
max hdop: 5
min satelites: 5
alpha radius: 50m

any suggestions to change something?

www.seabreeze.com.au/forums/topic.asp?TOPIC_ID=61207&SearchTerms=minspeed

Its still a problem as far as I know. Would be nice if we were all using the same GPS settings and program filters.

SO PLEASE SUGGEST ME WHAT I NEED TO ENTER

default filter is:

minimum speed: 3KT
max acce: 3msec
max hdop: 5
min satelites: 5
alpha radius: 50m

and what you suggest to put in:

minimum speed: ? KT
max acce: ? msec
max hdop: ?
min satelites: ?
alpha radius: ? m

and, btw, I also agree that beeing on the water and driving in 1 or 2 knots, waiting
for gust or wind was stoped MUST BE, and IT COUNTS in distance
why not ? distance is distance, no speed here is matter, isn't it?

As far as the team challenge goes, we don't force any filter values.

It's up to the sailor to post the most accurate figures they have available, however they arrive at them.

If the sailor believes that the most accurate figures are with a min speed of 0, then post that. If they believe that it's with a min speed of 5, or even 10 knots, then post that.


Personally I feel that 5 knots might be a bit high, but that's just me.

I use realspeed and occasionally gpsar, with filters set to norm

the only difference I do to norm is I have the min speed on the gps set to zero so it records everything, that way when you do chugg or swim it's all there.

I'd suggest checking your gps filters first

ok, and let me know about alpha radius ?

For the GTC, an Alpha is a 50m maximum deviation from the start and finish points, it's not the radius of the turn.
Total length not more than 500m.

I find it useful to check for greater deviations, ie 60 & 70m, this will tell you if you're going too wide.

thanx