Contactless ice thickness measurement device

• Problem

At present, measuring ice thickness on rivers and lakes is a time-consuming process using ice drilling and thickness measurement using a specialized measuring scale. This approach is impractical for large area survey and also makes it difficult to identify ice thickness reduction zones caused by water currents.

• Solution

A portable contactless ice thickness measurement device allows you to quickly and easily measure ice thickness. The advantage of this type of manual contactless measuring device is the ability to display ice thickness measurement data on the device display in real time as well as to store the survey data locally or to send to a remote server. Lightness of the device allows it to be used for mapping large areas of ice thickness using a drone or other unmanned platform.

• Purpose of technology

The purpose of the technology is to facilitate and speed up the process of obtaining ice thickness measurement data. The potential future goal is to fully automate the data collection process using: (a) stationary equipment; (b) equipment on board flying or moving platforms.

• Description of used technology in prototype

Contactless ice thickness measurement device uses EDI developed clocked comparator based ultra-wideband (UWB) pulse radar sensor technology. One of the most important components of this technology is the clocked comparator signal converter used in the radar receiver. The use of such a solution makes it possible to receive a periodically recurring signal below noise level, thereby improving the efficiency of the receiver and reducing the need for high radiated power. Therefore, the use of the clocked comparator contributes to energy efficiency, which is particularly relevant for use in mobile equipment. In addition, the receiver uses equivalent time(stroboscopic) signal conversion principle, allowing a recurring high-frequency signal to be transformed into a low-frequency equivalent time signal. The use of this operational principle reduces the cost of the equipment, since the more widely available and cheaper standard components can be used in the low-frequency equivalent time signal processing.

• Principle of operation

Principle of operation is based on short time radio pulse transmission in the environment. As radio pulses move into the environment, they are reflected from different layers of surface with different electrical and magnetic properties, in case of ice thickness measurement device: air-snow, snow-ice, ice-water. Part of electromagnetic pulse energy is reflected, but part of it propagates further, thereby enabling the measurement of multiple layer parameters. The receiver captures reflected pulses and transforms them into a digital signal. The received signal is analyzed by data-processing block which using implemented algorithms calculates snow and ice thickness.

• Properties

This technology does not require direct sensor contact with the measurement environment to determine the thickness of the snow and ice, so it is possible to design contactless measurement devices.

Technology used in combination with specialized signal processing techniques enhances receiver sensitivity [¹] The high sensitivity of the receiver enables the use of a lower power transmitter which reduces radiated power in the environment and also improves the energy efficiency of the device.

• Current results

At present EDI has developed a prototype of ice thickness measuring device which has been tested in real conditions on Lake Jugla and in Jelgava on river Lielupe. Under realistic conditions (winter 2019), a thin ice thickness measurement of 5 cm with an accuracy of ~ 1 cm was tested. Based on the feedback and suggestions from the potential users of the device, the hardware and software of the prototype was improved and experimental validation of thin ice measurement starting from 3 cm was carried out in laboratory conditions. This parameter has yet to be confirmed in real-world experiments, but so far there has not been adequate weather conditions (due to the warm winter) to conduct this test.