30 Apr Tilt Capabilities of the GNSS Receivers

The recent development in the GNSS technology has brought about a new capability of GNSS receivers to collect data in a tilt position. Some of the receivers are “good” enough to capture data even at a tilt angle of 30 degrees. Looking back at the principle guidelines of good surveying practic i.e. when running a traverse, the acute angle between the traverse legs should not be less than 30 degrees whereas the obtuse angle should not be more than 120 degrees. However, these were measures put in place to help have a strong network on points, increase accuracy, and understand the distribution of errors using the error ellipses.

The same good old surveying principles are mirrored in the GNSS technology and referred to as Dilution of Precision (DOP) classified as position, horizontal, vertical, and Geometric. The point is that the satellites should be well distributed in the sky to give a better accurate position in precision. Data collection/picking corner buildings are always not easy with the GNSS receivers, maybe because the building is blocking the satellites and probably the multipath effect prolonging the convergence of the satellite signals hence a float solution. Indeed, afloat solution isn’t a bad result, however, it doesn’t meet the precautionary checks for a precise solution. In my opinion, in such a case you can as well use a handheld receiver with a 1-meter accuracy to pick the corner building.

The question, therefore is, to what degree should the tilt technology be used? Imagine the distribution of the satellites at a 60 degrees tilt? I still advocate for the use of the offset method.