Automated Determination of the Average Air Temperature by Means of Sound Speed and Cross-Correlation Function at Precise Distance Measurement

U radu je izloženo automatizirano određivanje prosječne temperature zraka približno duž putanje svjetlosti pri preciznom mjerenju duljina elektrooptičkim daljinomjerima. Ta automatizacija određivanja prosječne temperature zasniva se na temelju fizikalnih saznanja da brzina zvuka u zraku ovisi o temperaturi zraka. Zato je trebalo izraditi instrumentarij koji će automatski izmjeriti vrijeme prolaza zvuka od prizme do elektroničkog daljinomjera. Iz izmjerenog vremena širenja zvuka i izmjerene duljine između prizme i elektrooptičkog daljinomjera (nekorigirane za utjecaj temperature) može se izračunati prosječna brzina zvuka, a zatim i prosječna temperatura zraka. U tu je svrhu prema originalnoj ideji razvijen i izrađen jednostavan i lagani instrumentarij, koji određuje vrijeme širenja zvuka pomoću kroskorelacijske funkcije. Tim instrumentarijem može se odrediti prosječna temperatura zraka približno duž putanje svjetlosti do 2 odnosno 3 km.The paper presents the automated determination of the average air temperature approximately along the light path in precise distance measurement with the electrooptical distance meters. This automation in determining the average temperature is based on the physical fact that the speed of the sound travelling in the air depends on the air temperature. It was therefore necessary to make the instruments that will measure the time of sound spreading from the prism to the electronic distance meter. From the measured time of the sound spreading and the measured distance between the prism and the electrooptical distance meter (not corrected for the temperature influence), the average speed of sound spreading can be calculated and then the average air temperature as well. For that purpose, a simple and light instrument has been made that determines the time of sound spreading by means of cross-correlation function. This instrument can determine an average air temperature approximately along the light path up to about 2 or 3 km

Automatic Determination of Deformations on Construction Objects with Test Loads

Na Geodetskom fakultetu Sveučilišta u Zagrebu automatizirano je određivanje deformacija građevinskih objekata u odnosu na neki pravac, pri raznim opterećenjima, elektroničkim teodolitom Leica (Kern) E2 i serijski priključenim laptopom. Da bi se dobila što veća točnost moguće je prema izboru fino vizirati 2 do 10 puta. Računalo automatski izbacuje grubo pogrešna mjerenja. Očitanje horizontalnog i vertikalnog kuta automatski ulazi u računalo i s duljinom izmjerenom do značke, unesenom prije početka mjerenja, računa se deformacija u odnosu na referentno mjerenje. Za probnih opterećenja poslije mjerenja u svakoj se fazi na ekranu mogu dobiti grafički prikazane razlike u deformaciji u horizontalnom i vertikalnom smjeru između različitih faza probnog opterećenja. U slučaju prevelike deformacije može se odmah prestati s povećanjem probnog opterećenja. Pri prvim probnim opažanjima u Kaštelima, kod ispitivanja promjena deformacija utovarno-istovarnog mola, pri promjeni probnih opterećenja, ta se metoda pokazala vrlo praktičnom. Postignuta standardno odstupanje određivanja pomaka na duljini 50 m s jednim finim viziranjem na mjernu značku je 0,2 mm, a s više finih viziranje može se očekivati i ispod 0,1 mm.The determination of deformation on construction objects referring to a certain line, when various load are involved has been made automatic at the Faculty of Geodesy, University of Zagreb by means of electronic theodolite Leica (Kern) E2 and on-line laptop. In order to achieve as high accuracy as possible, it is possible to perform fine pointing 2 to 10 times as selected. The reading of the horizontal and vertical angle enters automatically into the computer, and the deformation is computed with the distance measured to the target and entered before the measuring started, as related to the reference measurement. During the test loads it is possible to have graphically presented differences in deformation between various test loads phases displayed after the measurement in every phase. In case that the deformation is too large, one can immediately stop to increase the test load. During the first test observations in Kaštela, while testing the change of deformations on the pier for loading and unloading by applying the change of test loads, this method has proved as very practical. The standard deviation in determining the shift at the distance of 50 m with one fine pointing on to the target has reached 0.2 mm, and with more fine pointings, it can be expected to go below 0.1 mm