A high-resolution short-pulse radar for non-destructive investigations
An impulse radar, ImRa, is a radio-wave device, inteded for short-range detection of sub-surface objects or boundaries. ImRa consists of a control unit and an antenna unit. Different antennas for different purposed can be used.
The antenna unit is moved above the target area and it transmits continously short pulses to the ground and records the returning signals (echos). The control unit is based on a single-board computer. The measured radar image can be seen on a flat panel display as a two dimensional profile synchronized to the motion of the antenna unit or with a time scale.
The ImRa-system is portable and powered with rechargeable batteries. The radar can be used as a hand-held instrument in the field or mounted on a cart or vehicle for measurements indoors and outdoors. It is based on a single-board computer, which also can be used in heavy environmental conditions and at low temperatures. The measured data can be stored for archiving or post processing in the mass memory of the control unit.
The reflection of radio-waves from a target depends on the target geometry (size, shape and surface roughness) and on the target material difference compared with the surrounding material. The electrical properties of a material can be described with the relative dielectric constant. Looking at the dielectric constant values it can be concluded, that metallic objects should be seen always clearly, also dry objects in wet surrounding or vice versa should be seen and that the water content of a material has a major effect on its electrical properties.
The standard ImRa model is equipped with an antenna of 1 GHz frequency. This antenna is optimised for measuring distances up to 3 m with an accuracy of 1 - 15 cm depending on the material to be measured.
The 1 GHz antenna indicates e.g. the rot or decay in living trees and in power or telephone line poles, the thickness of snow and ice, the location of moisture faults, joists, pipes, cables etc. in concrete, wooden or other structures made of dielectric material.
Also antennas of other frequencies are available: an antenna of 1.5 GHz for more accurate applications and an antenna of 800 MHz for longer measuring distances.
Radar signal Processing (radar software):
Operating system: Linux
Real time dielectric constant calculations, distance in stead of time scale for homogenous material, adjustable scale
Real time colour intensity image display (radar profile)
Real time differential image display, (radar profile using a reference-image-technique)
Digital gain settings, echo stacking, software gain settings, image filters.
Scroll modes: synchronised with odometer wheel or time, adjustable scale.
"Oscilloscope" style display for gain settings and other calibration.
Data post processing: Data files are compatible with mathematical MATLAB-software (The Mathworks).
mRaLab image processing software:
Platform independent Java application
Multiple document user interface
Shows all data parameters used
Print and export file functions, opens original radar data and processed data files, saves processed data files
Several colour palettes, option to load new palettes
Flip horizontal/vertical, zoom in/out, quick contour, transparency and crop functions
Data processing filters: gain settings, vertical/ horizontal differential filters, data squaring, average subtraction, reference echo subtraction and reverse reference echo filter.
Horizontal / vertical smoothing and auto equalise filters.
CPU module PC/104 format, Linux operating system
Data storage: Local SSD or any USB media
Display: TFT, bright color LCD display.
Connectors: 2* USB, external SVGA, PS2 mouse, Ethernet 10/100, optional COM1, LPT1
Rechargeable 12V / 10Ah Li-Iron Phosphate battery (LFP), power: max 2.5A @ 12V.
Shielded antenna, type: two TEM-horn antennas, centre frequency 1.5 GHz, 1 GHz or 0.8 GHz
Maximum time difference 20ns
Scan rate: 100 scans/s
Odometer wheel (distance measuring wheel) and shielded measurement cable, length 5m
OTR: +25...-10°C, STR: +40...-40 °C
Control unit with battery pack: 40 cm*10 cm*28 cm, weight 7,2 kg. IP 65
1GHz antenna size 28*15*14cm, weight 2,5kg