Josef Krška

Czech Technical University in Prague | ČVUT · Department of Radio Engineering

An integral step in an ultra-wideband localization network installation is determining the positions of the fixed infrastructure nodes, the anchors. This process is time-consuming and usually requires specialized equipment. Additionally, it is difficult to achieve scalability, as any change or addition in the network requires a redetermination of t...

Ultra-Wide Band (UWB) real-time localization systems usually require either precise and robust synchronization of the anchor transceivers, or sufficiently stable clocks for methods referred to as "synchronization-free". Typically, reasonably priced crystals or TCXOs are utilized as frequency references for the UWB transceivers. Clock characteriza...

Ultra-wide Band (UWB) positioning systems are a system of choice for indoor positioning. Though UWB is more resilient against multipath propagation, the positioning accuracy can still be hindered in its presence. The positioning accuracy and availability can be improved by combination with other sensors, typically inertial ones. In the case of pede...

Ultra-wide Band (UWB) positioning systems estimate the user's position from several time-based measurements. While usually achieving decimeter-level accuracy, enhancing the measurements by additional measurements, such as Angle of Arrival (AoA), should improve the positioning performance and robustness. In this work, the design of our custom UWB-Ao...

UWB positioning combines time measurements from several devices to estimate the position of a target device. These measurements, however, are expressed in the device’s own timescale that is derived from its free running clock source, generally a crystal oscillator. The timescales are inherently offset and with different and time-variant drift, both...

The application of the impulse-radio ultra-wide band (IR-UWB) technology is already established in indoor localization. Usually, two-way ranging (TWR) or time-difference of arrival (TDoA) approaches are utilized. In this paper it is shown that it is possible to perform time of arrival (ToA) positioning with accuracy similar to the TDoA. The ToA met...

High-capacity impulse-radio ultra-wideband (IR-UWB) indoor localization systems are typically based on the time difference of arrival (TDoA) principle. When the fixed and synchronized localization infrastructure, the anchors, transmit precisely timestamped messages, a virtually unlimited number of user receivers (tags) are able to estimate their po...

This paper proposes an approach of TDoA positioning in UWB networks, where user tags localize themselves by means of exploitation of the broadcasted synchronization messages of the anchor network. Such approach promises unlimited number of localized devices, moreover, the position is available directly at the user terminal. The key challenge of thi...

In the ultra-wide band (UWB) localization networks the time difference of arrival (TDoA) is often used. The TDoA method is advantageous in comparison with two-way ranging approach, however, requires the UWB infrastructure of the network to be synchronized to a sub-nanosecond level. The wireless synchronization is in favor due to practical reason, n...

The UWB (Ultra-Wide Band) is a very popular technology allowing localization of users (tags) in a limited area. Two methods are used: TWR (Two-Way Ranging) and TDoA (Time Difference of Arrival). The TWR requires interrogation of the user equipment with several fixed nodes of the UWB network. This approach requires a lot of air-time. Moreover, consi...