Research on Absolute Distance Measurement

Low-cost remote distance and height sensing analog device for laboratory agriculture environments

“…The electronic measurement of distance [4] started to be using microwaves (radio frequencies) [9,10], sound waves (Doppler-based method) [11,12] and optical methods [13]. The optical-based methods can be further divided into longdistance concepts using lasers [14][15][16] and short distance concepts using infrared-light emitting diode (IR-LED based) light (up to 1 m). Many of long-distance (measurement of units and tens of meters) approaches employ partially optical-based signal processing (optical active elements, filters, etc.)…”

“…Many of long-distance (measurement of units and tens of meters) approaches employ partially optical-based signal processing (optical active elements, filters, etc.) [15,16] and interferometry of waves [15].…”

“…(a) The most precise measurement techniques require expensive devices like vector networks analyzer (VNA), spectrum analyzer, etc. [9,10,15,16]. The power consumption of these precise systems is very high.…”

“…(b) The size of full prototype (including various universal development boards) is enormous [17,18] for applications similar to the one discussed in this paper. (c) The majority of systems targets on direct measurement of frequency, time or time difference [9,11,12,[14][15][16]18]. (d) Concepts with average complexity use some digital embedded platform (development board solving complex signal processing) that increases costs [12,14,17,18], and also power consumption of such systems is quite high.…”

“…These systems require development of single-purpose software for digital signal processing or/and for performing the evaluation of an algorithm itself. (e) Methods fit for various ranges of distances, however, three groups can be distinguished: microwave [9,10] and IRbased [17][18][19] methods for short distances from millimeters up to one meter, ultrasound methods from centimeters to units of meters [11,12] and laser-based methods for long distances from meters up to kilometers [14][15][16]. (f) Nonlinear dependence of the sensed quantity on distance is standard for IR sensor-based systems [17][18][19].…”