Christoph Reck

Robust DOA estimation of SSR signals for aircraft positioning

Methods to estimate Directions of Arrival (DOA) on radio signals are susceptible to hardware and signal deficiencies. In the following, the robustness of four algorithms is evaluated by numerical and experimental tests. The focus lies thereby on Secondary Surveillance Radar (SSR) signals, but the algorithms can generally be used on any kind of radio signal. It will be shown that variants of the ESPRIT algorithm provide highly accurate DOA estimates on SSR signals even without calibration.

Verification of ADS-B positioning by direction of arrival estimation

ADS-B provides convenient means of air traffic control (ATC) for its low cost and simple ground station hardware. In a low percentage of cases, aircraft positions transmitted via ADS-B are error prone due to e.g. faulty wiring with onboard navigation systems. In the proposed approach, direction of arrival (DOA) estimation is used to verify ADS-B airborne positions. The potential positioning error of ADS-B is thereby evaluated by comparing DOA estimates to DOA values calculated from ADS-B references and the sensor position and orientation. To prove the accuracy of the applied DOA estimation sensor, an additional measurement campaign using a dedicated measurement aircraft has been conducted.

Turbo equalization for evolved GSM/EDGE radio access network using higher order modulation

For evolution of the GSM/EDGE radio access network (RAN), the use of higher order modulation like 16- and 32-ary quadrature amplitude modulation (QAM) is considered in standardization for increased peak data rates and reduced transmission delays. In this paper, an optimized receiver design for different packet data transmission schemes is proposed. Turbo coding and turbo equalization is discussed for improved power efficiency and interference robustness. An efficient complexity reduction of the equalizer enables the usage of turbo equalization at a complexity comparable to that of separate equalization and decoding for turbo-coded transmission.

Full length article: Turbo equalization receivers for evolved GSM/EDGE radio access network using QAM modulation

For evolution of the GSM/EDGE radio access network (RAN), the use of higher order modulation like 16- and 32-ary quadrature amplitude modulation (QAM) is considered in standardization for increased peak data rates and reduced transmission delays. In this paper, an optimized receiver design for different packet data transmission schemes is proposed. Turbo coding and turbo equalization is discussed for improved power efficiency and interference robustness. An efficient complexity reduction of the equalizer enables the usage of turbo equalization at a complexity comparable to that of separate equalization and decoding for turbo-coded transmission.