In the paper we discuss the issue of creation of Radio Environment Maps (REM). In the literature REMs are considered as an enabler for the spectral awareness and support cognitive radios and frequency management systems. We present the functional architecture of the system and describe the role of main components. Next, we present the problem of the map creation. We describe the most suitable interpolation techniques and analyze their complexity. Some interpolation techniques require high computational power and consequently created maps better reflect the signal level. Next, we focus on the problem of measurements of the signal level in sensor networks. In the literature on the topic the sensor network usually is composed of many of sensors deployed within the area of a few square kilometers. Density and regularity of sensors arrangement impacts the quality of maps. On the other hand, the number of sensors used for tests conducted in a real environment usually is significantly limited. We discuss the problem how to model the sensor network and we describe the method which we used to measure the signal level in the sensor network operating in VHF/UHF bands in scenarios with one transmitter and two simultaneous transmitters. The received signal level measured by sensors was used as an input data for the interpolation and then maps were created for the Zegrze area. The quality of maps was assessed in terms of the correctness of the signal level estimation and transmitter localization.
The problem of spectrum management is relevant both for civilian and military systems, but it is much more complex when coalition operations are considered. Some limitations to efficient data exchange over radio channels are caused by the static frequency assignment method, inefficient frequency usage and lack of a common spectrum operational picture in NATO coalition operations.<p> </p> These problems could not be solved at the national level, thus it was of high importance to take up the discussion and to make a NATO-coordinated effort. For this purpose NATO has established the Research Task Group on Electromagnetic Environment Situational Awareness (NATO IST-146 RTG-069) aiming to work out the concept of the Radio Environment Maps (REM) enabling their users to obtain the spectrum operational picture and to minimize the level of interferences between wireless systems of coalition forces. One of the main goals of the research group is to define the architecture of the system and to specify interfaces to other systems in the area of frequency planning and constant spectrum monitoring. It is assumed that the function of the sensors may be performed by dedicated radio receivers, spectrum analysers, cognitive radios and Electronic Warfare (EW) or Intelligence, Surveillance, Reconnaissance (ISR) systems.<p> </p> In the paper we discuss the concept of the REM and the problem of the data delivery from other systems, e.g. EW systems equipped with a variety of sensors. We also present exemplary maps created using different methods and analyze how the deployment of sensors affects the quality of maps.
The Polish Land Forces (PLF) are equipped with diagnostic-repair shelters (pol. AD-R) designated to conduct the diagnostic test and repair of telecommunication devices. Surprisingly, there is lack of similar solutions when it comes to contemporary Electronic Warfare (EW) systems, which are equipped with specific devices. On ad-hoc basis this lack of capabilities can be compensated for with diagnostic and repair post of the AD-R shelter, designated for conducting diagnostic tests and repairs of radio devices that are in use in the PLF. However, available measurement equipment does not fully cover the frequency range and power levels typical for contemporary EW systems.<p> </p> Some improvement on this situation may be brought about by a new project aimed at designing a modernized AD-R shelter, named ADR-K. This shelter will have a wider range of measurement capabilities in relation to frequency ranges and generated power levels. However, the diagnostic equipment of this shelter will make it possible to perform only basic tests of the devices applied in EW systems which are used by the PLF. Neither extensive tests of these devices nor diagnostics of EW equipment used by the Navy or the Air Forces are possible.<p> </p> In the paper we discuss the needs for the diagnostic tests of devices used in typical subsystems of the EW system. We present the capability of the Military Communication Institute in the area of test-checks and calibration of direction finders. Finally, we characterize the capabilities of AD-R and ADR-K shelters in relation to typical EW system and their equipment.