Determining a Technique for Transmitting Measuring Data on the Spatial Positioning of the Piercing Head in Small-Size Installations During Controlled Soil Piercing

Abstract

For laying of underground utility systems in urban conditions by the method of horizontally directed soil piercing, small-sized units are designed. Such units should have measurement systems for determining the spatial position of the piercing head. In known systems, the surface layer of the soil is used as a data transmission line for transmitting measurement information. This method of transmitting information signals in urban conditions is not very acceptable. Ground-based objects reflect electromagnetic radiation of the head transmitter which leads to distortion of the directional diagram of the emitter and complicates the reliable reception of measurement information. It was proposed to use an autonomous measuring system with an operating frequency of 5 GHz based on Wi-Fi technologies and an unconventional method of transmitting measurement information using hollow steel bars in the piercing unit itself. This transmission line has periodic discontinuities because of the bar design. These discontinuities accumulate as the piercing head advances. For the basic vibration type Н 11 , more accurate analytical expressions were obtained for calculating the power transfer coefficient of the measurement signal in such non-uniform lines. It was shown that inhomogeneity of the transmission line in comparison with its surface resistance does not significantly affect the transmission coefficient. For example, damping in the line increased by 1.2 dB with the maximum length of inhomogeneity of 5 mm and the total length of jointed bars of 50 m. It has been theoretically proven that the range of soil piercing with reliable signal reception can be up to 50 meters. The proposed method for transmitting information signals makes it possible to reduce the transmitter power, ensure noise immunity of the measuring system, and reliable reception of the measuring information throughout the entire piercing path