T&A Survey’sTISA 2D is a simple, safe and clear way to receive data about the subsurface. The TISA 2D can be used in various shallow and deep underground applications where surface radar operation is not feasible. What makes TISA unique is it's primary reflection mode, where both antennas are located in a single tool inside the same borehole.
Reflection Mode What makes TISA 2D unique is its reflection mode of operation where both antennas are located in a single tool inside the same borehole. The transmitted pulses are reflected by a nearby object and detected by the receiver antenna. The depth of the antenna system and the measured pulse two-way travel time defines the 2D position of the detected object. Urban Environments The TISA 2D tool can be used in various shallow and deep underground applications where traditional surface radar cannot penetrate and is beyond their range. Dense urban environments present different challenges than open unobstructed areas where ground penetrating radar (GPR) is most often used. What if the buried object is under a concrete slab or under a building?
TISA 2D BHR has the ability to aid the search and the recovery of such targets. When there is a contrast of electromagnetic properties between the target and its surroundings, it is possible to isolate and precisely observe where the buried object is located.
Applications Given the working principle of GPR with its advantages and limitations, the most common applications of TISA 2D are listed below. This list is far from complete and any situation where subsurface structures exist with different electromagnetic properties to their surroundings pose a potential opportunity for the use of TISA 2D.
Data Processing Collected data is displayed, processed and interpreted using T&A’s property software TISAMap, providing unsurpassed accuracy and clarity of the results.
Transillumination mode measurements, with transmitting and receiving antennas in two different boreholes, extends the area of application.
TISAMap is the specifically designed software package to display, process and interpret radar data recorded with TISA 2D. Besides standard processing steps such as Dewow and AGC gain application, TISAMap allows to subdivide the recorded depth interval into user defined horizontal layers. This feature is especially useful for vertically recorded radar profiles which are often affected by changing soil conditions with depth. By insertion of several layers the user has the ability to apply individual processing parameters to the different soil layers (e.g. clayish vs. sandy layers).
Interactive hyperbola fitting allows the estimation of the ground velocity and hence the permittivity for each layer. Subsequently, a time-distance conversion can be applied to locate a detected object in space. TISAMap allows for an efficient and state of the art processing, interpretation and display of all your recorded borehole data.