Practical results of EDM-Height traversing

Abstract

The theory of EDM-height traversing is summarized and the necessary formulae are given. A practical test executed in Australia is discussed in detail, and the results of investigations in other countries are reviewed. In the Australian Test; a standard deviation for 1 km of reciprocal EDM-height traversing of ±4.3 mm was achieved. It is found that EDM-height traversing fulfils easily the specifications for third-order levelling and that it should replace geodetic levelling in many cases on economical grounds.

Staff errors in and the adjustment of ordinary levelling runs

“…Another powerful alternative for the measurement of small or large height differences is EDM-height traversing, where the scale and humidity errors can be reduced to 1 ppm or better and where the refraction errors are reduced because the lines of sight are parallel to the ground rather than horizontal. This method has been discussed elsewhere (Rueger 1995a(Rueger 1995bRueger & Brunner 19811982 and can be recommended as an effective replacement of (geodetic) levelling in many applications.…”

Precise height determination using simultaneous-reciprocal trigonometric levelling

“…5. Connecting surveys [14], [15] CONNNECTING SURVEYS Frequently, because benchmarks are located on walls, it is not feasible to set up the instrument over the bench mark. Furthermore, the accurate measurements of instrument height above ground marks are difficult.…”

“…By the development of total stations the investigation of precise trigonometric levelling methods have been considerably increased as an alternative technique related to the conventional geometric levelling [1], [2], [5], [8], [9], [11][12][13][14][15][16]. In the studies mentioned above, distance measurements and zenith angle observations are performed with separate instruments and reciprocal trigonometric levelling method is investigated.…”

Determination of Geoid Heights by GPS and Precise Trigonometric Levelling

“…In length of sight shorter than 500 metres, one may accept that the effect of deviation of verticle on height is negligibly small. So, the raw height differences from reciprocal trigonometric levelling will lead to the same value as GL [13], [14], [17]. In this regard, in this study PTL measurements are made with 100-150m average lengths of sight and no corrections have been made in the measured zenith angles due to deviations of vertical.…”

“…The first alternative method that might be used in such regions is the PTL. PTL method is more flexible than GL and reaches the GL accuracy by making the zenith angle measurements carefully, simultaneously and reciprocally using a special equipments and by selecting the length of sight shorter than 500m [2], [9], [13], [14], [15], [16], [17].…”