Integrating Geoid Model?

Are there any plans to integrate a geoid model? We use HTV2.0. Right now I’m just taking ellispoidal against a geoid average per site since geoids generally don’t have a significant shift sub-kilometer but it would be nice to be able to get real-time orthometric readings.

That would be a nice addition, I think I asked about this quite awhile ago.

Just remember that all the hard work is being done on a tiny computer that draws @200mAh. At some point it makes sense to hand tasks off to another device. I use MapIt GIS on an android tablet where I have control over the output spheroid and projection and can choose the geiod model from EGM96 (1deg x 1 deg) down to IGN RAF09 (1.5’ x 2.0’). MapIt connects via bluetooth to both reach and my Trupulse 360 rangefinder. I don’t have any links with MapIt, just note that it has a very good price for a very capable piece of software and has NO subscription to gradually chew into your bank balance.


Hi Simon,

What is the expected XYZ accuracy from your experience using combination of Emlid Reach RS + Trupulse 360 rangefinder?

Thank you.

Not very good I am afraid.

Reach IS cm accurate with a good fix. But tying your reach position to the Trupulse can introduce ferrous metal into the area.

It is the angle that presents the problem. When calibrated well, in an area with no magnetic interference you can expect +/- 1 degree which is +/- 1m at 60m or +/- 10 m at 600m. BUT BUT BUT little things can throw off the bearing without you realising it and therefore I would say more like +/- 5 degrees occasionally.

The issue is the lack of redundancy so you may or may not be good.

The solution ( yes there is one) is to shoot any remote spot from different positions the laser distance accuracy of +/- 0.5m (typical) does not suffer from big variability.

So two shots 30 degrees apart should deliver the same target point. If they don’t it is likely bearing error and you can use the intersection of the two ranges to confirm the true position (trilateration).

I have re-surveyed an archery fieldcourse which wasinitially mapped by a trupulse where the declination figure had not been correctly applied in the laser. Because there was no redundancy in the measurement the 10 degree offset was not picked up.

In practise if I am going to shoot and position remote objects I will a) ensure declination figure is correct b) ensure the worksite is compatible with collecting magnetic bearings (concrete is riddled with ferrous metal) c) pick 2 points 100m apart and shoot from 1 to the other, both ways. If the resulting bearings are not +/-1 degree ( so that can be 2 degrees different I.e a-b 271. b-a 89’ withexpected bearing being 270-90.) then I will recalibrate. If it still don’t work I will modify my plan to trilaterate.

Mapit happily pulls the Reach and Trupulse together.

So to sum up
The Trupulse 360 gives you a great sense of power.
But must be used with caution and be proved to deliver on site in the field each time you go out.

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