## 7 Further Improvements  
The results described in the article were obtained, in fact, by a working prototype, not by a market-level system. After the completion of the tests, a plan for improving the system was developed, taking into account all the identified shortcomings of the methodology and technology. Figure 14: Results of modeling the sensitivity of the created UAV-TEM system based on the obtained data: a model geological environment for which the 3D direct problem was solved: (**a**) 3D-view; (**b**) in plan; plots of absolute magnitude of EMF changes along survey lines 3 and 7 at the time delay of 80 \(\mu\)s (**c,d**) and 150 \(\mu\)s (**e,f**) for an object at a depth of 30 m (**c,e**) and 100 m (**d,f**). First, the measuring system should be lightened to improve the UAV weight to payload ratio from 1:1 to 2:1. This will lead to a much faster stabilization of the measurement system after stopping or turning the UAV, and greatly reduce the problem of data loss after turns, and during deceleration or acceleration. After that, a suitable distance will be determined by which the route missions should be extended outside the study area. It is important that after reducing the weight of the measuring system by 1.5-2 kg, a power reserve appears, which allows one to implement simultaneously with the UAV-TEM other methods of low-altitude geophysical surveys or other types of remote sensing. To keep the center of gravity closer to UAV the measuring systems should be rigidly attached to the UAV frame, and it is desirable to conduct the survey along a dense network and at low altitude. First of all, these are gamma spectrometry and lidar scans. The combination of several survey methods on one UAV will further increase the economic and geological effect of the technology. Second, a new meter unit is being developed that supports simultaneous measurements and recording. As shown in Chapters 5 and 6, there no needs to register the EMF decay at times later than 100-150 \(\upmu\)s, a new firmware has been prepared for the current switch, which increases the frequency of current pulses almost 100 times, from 0.125 s up to 0.001 s. This provides a significant increase in the dense of the data. The possibilities of filtering noise increase, the transient will be stacked with 400-500 decays instead of 6-8 decays (as in Figures 8b, 10b, 11b and 13b), or it will be possible to set a more detailed exploration network along the survey line. Third, to clarify the early times of transient after cut off the current in the transmitter line, it is necessary to reliably separate the effects of the current pulse after cut off and the response of the medium. The current cut-off signal in the transmitter line must be measured instrumentally to be taken into account, but not simulated analytically, as is done in this work (Section 6, Figure 13). After subtracting the effects of the current turn-off signal and the impulse response of the receiving sensor from the early times of the transient, the transient data will describe the geological environment. This will allow modeling the first meters of the geological section, and will also improve the quality of the inversion in general. Fourthly, one-dimensional data inversion, as done in this work, is irrational. Inverting the transient response of each observed point is performed by multiple calculations of the direct problem until the minimum convergence between the model and measured sounding curve is achieved. The density of the observations using UAV-system is much higher than the onshore methods which makes the expenditure of human time enormous. In addition, 1D-inversion does not take into account the influence of effects from neighboring points, and one of the most important advantages of the UAV-TEM is the possibility of cost-effectively obtaining a dense survey. More importantly, 1D inversions do not always provides adequate reconstruction of local 3D objects, especially in complex environments in the sections with tectonics.