Understanding Navigation

[Bricoop]

Figured I'd start a new thread, rather than clog up the Dakar 2017 post. Based on the translation, it sounds like Coma is going to make finding the WPs more difficult. In the past, when you were ~800m from a WP you would receive a directional arrow to help you find the WP. This year it sounds like you won't be notified until you are within 300m. The difference being you no longer have those directional arrows after notification. I assume the graded roads will have WPs on the road, but in the dunes it sounds like there has been issues with top teams finding WPs. Is anyone familiar with how close to a WP a vehicle needs to be to a WP to trigger crossing it?

Because I work better with illustrations, here's how I would use this technique in a real race. This is just based on my research and what I've read from many of you guys.

Co-dog indicates a WP is coming up. We cruise through and get a beep at 2 locations (unclear how this works exactly if it is a sustained beep or one every time you enter the 300m radius of the WP). Based on that we can identify how far we traveled within the notification circle. No indication we hit the WP so we've got to turn around to find it, mind you each of these 300m circles is an area of ~22acres, not small! So what do we do? We go to the location of the second beep. Based on our original heading of 100 degrees, we'd now be heading @ 280 degrees after we turn around. Based on this chart, the co-dof would know I need to head 54.14 degrees off my current route. Have the driver pin it for 300m at a heading of 334.14. If that doesn't work, go back to that second beep and adjust 54.14 degrees the other way other way for 300m at a heading of 225.86(or from the first beep at 154.14 degrees).

Distance traveled - Degrees off route
50 - 57.10
100 - 56.50
150 - 55.51
200 - 54.14
250 - 52.39
300 - 50.28
350 - 47.82
400 - 45.03
450 - 41.92
500 - 38.53
550 - 34.86

Like before, green is original route, yellow dots indicate notification points and purple is after we've turned around with our revised heading.

There are a lot of variables that can affect this such as sensitivity of the GPS, ability to measure distance between notifications and the ability to mark and return to specific locations.

How do you guys think the pros will solve the new challenge?

 

[TJERGENSEN]

The sonora rally had the same 300 m 1st alert and then you had to be within 50 m to get the actual W.P.. it is very important to get you're bearing when you get the W.P. both driver and co dodd need to be on same heading. if you loose that landmark you must go back to last known intersection (roadbook). you cant do it with math. because 100 yds at the beginning can ne a mile at the w.p.

 

[TJERGENSEN]

The pros won't have any problems with it. they can stay on a heading . it's the hobbyists that will be lost all night. also there is a botton you can push at anytime and an arrow pops up leading you to the next w.p. it is like a 1 hour penalty for pushing it.

 

[Bricoop]

Good info, thanks @TJERGENSEN Did you run the Sonora Rally? If so, how difficult was it to find the 50m circle after hitting the 300m circle?

 

[TJERGENSEN]

yes we did Sonora rally . It is not that hard to hit the 50 m because a direction arrow comes up at 300 m on the rally comp computer showing which way to go to the w.p. only if a big dune is in the way does it get hard to hit the actual w.p.
It is like being lost and then found every few minutes for a whole day.

 

[Bricoop]

yes we did Sonora rally . It is not that hard to hit the 50 m because a direction arrow comes up at 300 m on the rally comp computer showing which way to go to the w.p. only if a big dune is in the way does it get hard to hit the actual w.p.
It is like being lost and then found every few minutes for a whole day.

I see, my suggestion is under a format where there is no arrow when you hit the 300m ring, which is how I interpreted Coma's translated text.

 

[TJERGENSEN]

Im pretty sure dakar uses a similar computer, i think it is called a tripy. tells you heading, tells you when youre speeding, and has the 2 rings.

 

[Bricoop]

Im pretty sure dakar uses a similar computer, i think it is called a tripy. tells you heading, tells you when youre speeding, and has the 2 rings.

Up until this year, Coma announced some changes a couple weeks ago, in French.

 

[Hog Wild]

Im pretty sure dakar uses a similar computer, i think it is called a tripy. tells you heading, tells you when youre speeding, and has the 2 rings.

Tripy is used in the team support vehicles, not the competition vehicles. It shows maps and the path from bivouac to bivouac.

The race vehicles use the Unik 2 GPS + Sentinel unit (moto and auto versions). Autos usually have two of these, while bikes have only one. Details are here:
ERTF - Accueil

All competitors also have the Iritrack (newer version), which provides sat phone communications to the race org, and alerts the org if the vehicle experiences a severe impact or is upside down. It also provides live tracking to the race org so they know where everyone is.

There's also odometers, heading repeaters (digital readout), and other stuff.

The primary things for navigation are the roadbook, odometer, and digital compass heading.

 

[GEO_DXB]

Tripy was used this year at Dubai International Rally and we found it hardly ever useful. Its probably good for support vehicles, but it is too slow for race cars. In our car we had a fair bit of issues with navigation under pressure with it. The unit tends to freeze at WP and for a while needs to "look" for new direction and can easily show you different things within a few secons. Most participants complained about it in this or other way.


For us the usual ERTF solutions - UNIK and Sentinel are way easier to use. With 2 GPS screens of UNIK you can also pretty much disregard the terratrip as you still have most of the measurements coming directly from a GPS, very comfy.

 

[TJERGENSEN]

Looks like the unik is just like the procomp unit we used at Sonora . it has the circle and the arrow. does the timing, and has the pass alert.