Home > Research and Market Data > Technology research > Research > The state and use of the spectrum > Automatic Interference Monitoring System

The AIMS system will allow the measurement of the amount of interference compared to actual signal strengths across a broad frequency range. The system is expected to be deployed for a number of days at locations of interest around the UK. The system will be unmanned during deployment, operating autonomously until the system is collected and data retrieved. This will allow spectrum usage and quality measurements to be made at a range of urban, suburban and rural locations. These will be repeated at regular intervals to monitor quality, usage and the impact of new developments over time.

The AIMS comprises the following main components:

• Ultra-wideband antenna. This will be omnidirectional, vertically polarised and cover the frequency range 100 MHz to 10.6 GHz. It is being designed and built by Queen Mary University London (QMUL). A Low Noise Amplifier (LNA), with a noise figure of approximately 3 dB, will be integrated into the antenna to ensure a low system noise figure of less than 4 dB across the entire frequency range.
• Receiver subsystem. The receiver subsystem comprises a spectrum analyser, RF switch, noise source and other ancillary equipment. The bulk of the analysis will be based on processing the I/Q outputs of the analyser.
• Analysis software. This will comprise an emitter database, test editor, calibration database, DVD viewer plus the remote desktop functionality of Windows XP.

Figure 1 Automatic Interference Monitoring System (AIMS) schematic

Design of a suitable antenna which can operate successfully over the required frequency range is a significant challenge. Advanced electromagnetic simulation has been used to design a novel antenna concept which can meet the challenging performance requirements for the AIMS system. From this concept a compact, ultra-wideband antenna has been designed and built. The antenna is close to omni-directional across the full frequency range, and incorporates an integral Low Noise Amplifier (LNA) to ensure a good system noise figure.

Figure 2 Wideband antenna prototype design for the AIMS system

Project status

The design of this system is well underway. Novel and advanced algorithms have been implemented which will allow the system to analyse state of the art signals and monitor interference levels. The system design is suitable for rolling upgrades to the software ensuring algorithms can be employed to maintain analysis of state of the art signals.

Initial measurements with the system will begin early in 2006. A programme of measurements will be established to allow long term analysis of the spectrum, allowing the impact of new developments such as UWB for example, to be quantified.

The project is now complete and you can download the final report below.

• AIMS Final Report [pdf]
• Appendix A [pdf]
• Appendix B [pdf]
• Appendix C [pdf]
• Appendix D [pdf]
• Appendix E [pdf]

Back to top