SurePath unboxing

[Jtim3032]

@MattP @disland Sorry guys I am so busy right now that I can't always follow the BOS threads. Sure-Path is currently fine for collecting GPS co-ordinate data for use in an approved homologation (survey) program such as Emmanuel Lion's "Water Ski Homologation". After marking the entrance gates, Sure-Path can indicate how far off "ideal" any buoy is, but the actual official homologation has to be done within software that also compares the buoy's distance from various adjacent buoys (axials and diagonals). So think of Sure-Path as an approved replacement for the Total Station traditionally used for surveying buoy positions.

 

James

[Jtim3032]

@Horton yes, yes, yes....I need to have an FAQs page on the web site. There is already a "Troubleshooting and FAQs" but this needs expanding to a general questions page where the details of the technology can be explained better. A lot of stuff can be answered by going back to the IWWF Rules which changed quite a lot this year in regard to boat deviations.

 

For the nerds...the official deviation figures in the "Tournament Mode" summary screen are "the average of the two highest deviation readings towards the skier in a range from 10 metres before the buoy to 10 metres after the buoy". However, this 20 metre range is a little large and the resultant figure can mislead a driver who might get a reading of say +10cm for buoy one when in actual fact he offsided the skier when the skier was actually at the buoy. He could do this for instance by being -10cm "at the buoy" but +10cm at 9 metres after the buoy.

 

Thus at the request of some very senior drivers, I added "Training Mode". This gives the boat's deviation at the first reading taken after the boat is at the guide buoy and therefore gives the driver a better picture of what he is actually doing to the skier. The numbers however cannot be used in tournament as they are not calculated strictly according to the Rule.

 

Some background...the 20 metre range was introduced to stop a driver weaving his way down the course to help the skier even whilst staying within the 20cm tolerance. The 20 metre range catches the maximum deviation towards the skier and you fail the cumulatives very quickly indeed, usually by buoy 2. The rule does this very well but as previously explained, does not really say what is happening to the skier.

 

Going forward, as we collect and analyse "big data", we will get a much better picture of how the rule should be worded in order to stop undesirable driving whilst still giving a good picture of how the skier is being affected.

 

For driver development, it won't be long before we can offer drivers on demand analytics of their driving, either over a tournament, during a day or over longer periods of time. Things like deviation distributions at each buoy for a given rope length and boat speed will be available as well as cool things like how the boat moved predominantly at/after each buoy.

 

James

[Jtim3032]

@MattP the problems with using Sure-Path to give co-ordinates for ZO are twofold:

 

1: The Sure-Path co-ordinates are not accurate with respect to absolute position, rather they are only super accurate with respect to the base antenna position, and the base position is only plotted typically to within 10 metres (because it doesn't need to be). Therefore, entering SP co-ordinates into ZO could give wildly wrong results.

2. ZO itself is only accurate to +/- 2 metres in ideal conditions (so called Differential GPS or DGPS) and therefore, even if the co-ordinates from Sure-Path were accurate in an "absolute" sense, ZO readings could still be up to 2 metres away from that position. Anyone who has watched a GPS "scatter plot" live will know that this variance occurs over quite short periods of time (ie one or two minutes) and so no two passes will be the same in terms of course start timing. I have been in the boat many times when the driver and TC map the course at the start of competition and when they do a return pass to check, the result seems wrong by a metre or so. This is not because they mapped the course wrong, rather it is inherent in the technology.

 

James

[Jtim3032]

@klindy @Stevie Boy yes data collected by Sure-Path and similar systems will almost certainly be used in some sort of monitoring program, even if only for internationally ranked drivers. One thing however that has been markedly missing until now is a proper privacy policy that ensures that drivers know how and when the data is collected, stored and the purposes to which it will be used. You may have heard of the GDPR regulations which already exist in Europe. Maybe other (con)federations need to publish something similar.

 

James

[paul]

Can this be run at a site without cell phone signal - ie 900mhz radio or something similar? Does the base have the computing power or does it have to be sent to the web?

[Jtim3032]

@paul it is possible to use radio modems for the link between base and rover albeit we don't usually recommend it on reliability grounds. It also adds a lot to the cost. All the real computing power is in the GPS onboard chips and the rover phone. The online server is just a relay station and does not do any processing as such. For lakes with no cell coverage, we are working on getting a WiFi system together which we know will work. We are not far off that now. WiFi has all sorts of advantages also for transmission of video from boat to shore for judging purposes. Keep an eye on the website for progress on this.

 

James