In this paper, we present a hybrid local positioning and communication system under development within the scope of the EU funded RESOLUTION project. Very stringent requirements to positioning accuracy combined with tight bandwidth limitations demand innovative approaches to combat channel multipath effects. Closely spaced multipath components are the dominant cause of error in the system. Results of system simulations utilizing indoor channel scenarios and measurements using a discrete prototype are presented to prove the possibility of achieving the design goals in spite of limiting spectral regulations.

The rapid development of Internet of Things (IoT) has led to more and more devices using ISM frequency bands. Because they are not time synchronized, medium access collisions are unavoidable. The probability of such a collision is usually reasonably low; however, it increases with the number of transmitters competing for the same frequency channel. For this reason, ISM bands’ occupancy is regularly monitored by researchers. This paper presents the results of the measurement campaign during which a selected part of the 868 MHz ISM frequency band was monitored for the presence of transmissions in six locations in various residential areas in Warsaw, Poland. For the purpose of the campaign, a dedicated measurement set-up comprising a software-defined radio (SDR) module was assembled. The measurements results showed that the channel occupancy is in most cases lower than 1% with a maximum observed value of 2%. The paper presents selected characteristics of the detected signals. Additionally, distribution over time of the detected signals was used together with the Monte Carlo simulations to analyze how long idle time blocks are available for new transmitters that could be deployed in the band under testing.

The paper presents measurements results of the propagation channel for three types of indoor environments. Basing on these results statistical analysis and comparison of obtained data are presented. Short review of channel profile measurement techniques are also presented. The paper includes discussion of indoor channel propagation type influence on positioning systems accuracy. Measurements were part of EU VI FP RESOLUTION project, in which WUT was responsible for propagation and antennas work package.

This paper presents the concept of a radiofrequency (RF) sensor designed to estimate the mass of the regolith acquired by a sampling device or excavator in planetary environments. The sensor utilizes a microstrip line with an open end as the sensing element, with the mass estimation based on measurements of the phase of the reflection coefficient (S11 of the scattering matrix) for the line immersed in the regolith. The Rotary Clamshell Excavator (RCE) was employed for the experimental evaluation of the sensor’s performance. The RCE successfully passed an environmental test campaign, demonstrating its suitability for future lunar missions. The test results indicate that the RF sensor can estimate the mass of the acquired regolith with reasonable accuracy, approximately 15%, making it a viable solution for rough mass estimation in sampling devices and excavators.

Paper presents a proposal of method for closely spaced paths mitigation for indoor location system based on spread spectrum signals. At the beginning issue of closely spaced paths influence for the accuracy of TO A determination is explained. In the following part results of indoor propagation simulations are presented. These simulations show relationship between delays and directions of arrival of power delay profile components. The proposal of simple four-element null steering antenna array, which can mitigate this effect, is proposed. The paper contains also results of measurements showing influence of multipath propagation to coarse code synchronization.