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<p>Nowadays, mobile phones have greater functionality; a camera, color LCD screen, wireless LAN, Bluetooth, IrDA and others. In the near future wider variety of new functionalities will be added, from high quality voice, high definition video to high data rate wireless channels. As consumer electronics integrate greater functionality and high operating frequencies, their emissions will exceed the specified limits, most of these emissions will be a result of the internal interferences in the mobile phone. Moreover higher operating frequencies will be required to improve the quality of these functionalities, something that will make it more difficult to control these interferences. Internal or external sources of electromagnetic interference can degrade the performance of sensitive analog/digital circuits inside the mobile phone. Moreover the electronic device must satisfy a host of global regulations that limit it’s susceptibility to these interferences, as well as the interference emitted by the device itself.</p><p>Therefore designing a new electronic device to perform new and exciting functions will not be a pleasant task if it can not meet certain specifications and function as required to adhere to certain global regulations.</p><p>This thesis project investigates the sources of interference inside a mobile phone; mainly the electromagnetic interferences and its effect on the radio transceiver focusing on the GSM receiver sensitivity. This report is a result of intensive research, an investigation of possible sources of interference, also actual measurements were performed; RSSI, OTA and sniffing measurements; to identify the physical sources of interferences, and their effect on the receiver sensitivity. Finally solutions were recommended and implemented to suppress the interferences due to different sources, mainly through filtering, shielding or proper grounding of signals and components/subsystems in the mobile phone.</p>

Nowadays, mobile phones have greater functionality; a camera, color LCD screen, wireless LAN, Bluetooth, IrDA and others. In the near future wider variety of new functionalities will be added, from high quality voice, high definition video to high data rate wireless channels. As consumer electronics integrate greater functionality and high operating frequencies, their emissions will exceed the specified limits, most of these emissions will be a result of the internal interferences in the mobile phone. Moreover higher operating frequencies will be required to improve the quality of these functionalities, something that will make it more difficult to control these interferences. Internal or external sources of electromagnetic interference can degrade the performance of sensitive analog/digital circuits inside the mobile phone. Moreover the electronic device must satisfy a host of global regulations that limit it’s susceptibility to these interferences, as well as the interference emitted by the device itself. Therefore designing a new electronic device to perform new and exciting functions will not be a pleasant task if it can not meet certain specifications and function as required to adhere to certain global regulations. This thesis project investigates the sources of interference inside a mobile phone; mainly the electromagnetic interferences and its effect on the radio transceiver focusing on the GSM receiver sensitivity. This report is a result of intensive research, an investigation of possible sources of interference, also actual measurements were performed; RSSI, OTA and sniffing measurements; to identify the physical sources of interferences, and their effect on the receiver sensitivity. Finally solutions were recommended and implemented to suppress the interferences due to different sources, mainly through filtering, shielding or proper grounding of signals and components/subsystems in the mobile phone.

Precise and robust positioning through Global Navigation Satellite Systems (GNSS) is instrumental to a wide gamut of modern systems. The integrity of GNSS signals is increasingly compromised by Radio Frequency (RF) interference, presenting a substantial threat to the performance of GNSS receivers. This vulnerability is of particular concern for Unmanned Aerial Vehicles (UAVs), whose critical functionalities depend heavily on reliable GNSS positioning. Given their complex designs and high maneuverability, UAVs present a distinctive and powerful platform for the exploration and mitigation of GNSS RF interference. This work investigates two complementary but related aspects: (i) the detection of internal RF interference with the GNSS receiver and (ii) the localization of external RF interference sources, utilizing the advanced capabilities of UAV platforms. The detection methodology (i) synthesizes insights from existing literature by selecting RF interference detection methods compatible with observables from standard GNSS receivers. It also innovatively employs ideal spectral masks to estimate the impact of interference. In addition, the localization methodology (ii) introduces a novel UAV-centric technique that leverages the characteristics of GNSS antennas and UAV maneuverability. A concept of radiation heatmap has been developed to transform the antenna’s radiation pattern into a heatmap, indicating a possible bearing toward an RF interference source. Subsequently, a concept of triangular intersection is introduced to fuse multiple radiation heatmaps into a single localization heatmap, indicating the locations of interfering transmitters. Through this work, a comprehensive framework has been established, allowing UAVs equipped with GNSS receivers to detect internal interference and localize external RF interference sources. This dual approach contributes significantly to the monitoring of the GNSS spectrum and enhances the performance of GNSS-dependent applications. / Exakt och robust positionering genom Globala Navigationssatellitsystem (GNSS, från engelskans Global Navigation Satellite Systems) är avgörande för en mångfald av moderna system. Integriteten hos GNSS-signaler hotas alltmer av interferens från radiofrekvenser (RF, från engelskans Radio Frequency), vilket utgör ett betydande hot mot prestandan hos GNSS-mottagare. Denna sårbarhet är särskilt bekymmersam för obemannade luftfartyg (UAV, från engelskans Unmanned Aerial Vehicle), vars kritiska funktioner är starkt beroende av tillförlitlig GNSS-positionering. Med tanke på deras komplexa konstruktioner och höga manövrerbarhet utgör UAV:er en distinkt och kraftfull plattform för utforskning och mitigering av GNSS RF-interferens. Detta arbete undersöker två kompletterande men relaterade aspekter: (i) detektion av intern RF-interferens i GNSS-mottagaren och (ii) lokalisering av externa källor till RF-interferens, med användning av avancerade UAVplattformar. Metoden för detektion (i) syntetiserar insikter från befintlig litteratur genom val av metoder för upptäckt av RF-interferens som är kompatibla med observerbar data från standarden för GNSS-mottagare. Den använder dessutom “ideala spektralmasker” (från engelskans “ideal spectral masks”) innovativt för att uppskatta interferensens påverkan. Dessutom introducerar lokaliseringstekniken (ii) en ny UAV-centrerad teknik som utnyttjar egenskaperna hos GNSS-antenner och UAV:ers manövrerbarhet. Ett koncept för strålningsvärmekarta har utvecklats för att omvandla antennens strålningsmönster till en värmekarta, vilket indikerar en möjlig riktning mot en källa till RF-interferens. Därefter introduceras ett koncept för triangulär skärning för att sammanfoga flera strålningsvärmekartor till en enskild lokalisationsvärmekarta, vilket indikerar placeringen av störande sändare. Genom detta arbete har ett omfattande ramverk etablerats, vilket möjliggör för UAV:er utrustade med GNSS-mottagare att upptäcka intern interferens samt lokalisera externa källor till RF-interferens. Denna dubbla strategi bidrar avsevärt till observationen av GNSS-spektrumet och förbättrar prestandan för GNSS-beroende applikationer. / Presné a robustné určovanie polohy pomocou globálnych navigačných satelitných systémov (GNSS, z angl. Global Navigation Satellite System) je kľúčové pre široké spektrum moderných systémov. Integrita signálov GNSS je čoraz viac ohrozovaná vysokofrekvenčnou elektromagnetickou (RF, z angl. Radio Frequency) interferenciou, čo predstavuje významnú hrozbu pre výkonnosť prijímačov GNSS. Táto zraniteľnosť je obzvlášť znepokojujúca pre bezpilotné lietadlá (UAV, z ang. Unmanned Aerial Vehicle), ktorých kritické funkcionality sú vo veľkej miere závislé od spoľahlivého určenia polohy. Vzhľadom na ich zložitý dizajn a vysokú manévrovateľnosť, UAV predstavujú výnimočnú a bohatú platformu pre skúmanie a mitigáciu RF interferencie. Táto práca skúma dva komplementárne, ale súvisiace aspekty: (i) detekciu vnútornej RF interferencie s využitím prijímača GNSS a (ii) lokalizáciu zdrojov vonkajšej RF interferencie s využitím pokročilých schopností UAV platformy. Metodika detekcie (i) syntetizuje poznatky z existujúcej literatúry výberom metód detekcie RF interferencie, ktoré sú kompatibilné s pozorovaniami zo štandardných prijímačov GNSS. Taktiež inovatívne využíva ideálne spektrálne masky na odhad vážnosti vplyvu interferencie. Okrem toho, metodika lokalizácie (ii) predstavuje nový prístup zameraný na UAV, využívajúci charakteristiku antén GNSS a manévrovateľnosť UAV. V rámci tejto práce bol vyvinutý koncept radiačnej teplotnej mapy, ktorý transformuje radiačný vzor antény na teplotnú mapu, indikujúcu smer k možnému zdroju RF interferencie. Následne bol predstavený koncept trojuholníkovej priesečnosti, spájajúci viaceré radiačné teplotné mapy do jednej lokalizačnej teplotnej mapy, indikujúcej polohy rušiacich vysielačov. Prostredníctvom tejto práce bol vytvorený komplexný rámec, umožňujúci UAV, ktoré sú vybavené prijímačmi GNSS, detekovať vnútornú interferenciu a lokalizovať zdroje vonkajšej RF interferencie. Tento duálny prístup významne prispieva k možnosti monitorovania GNSS spektra a zvyšovania výkonnosti aplikácií závislých od GNSS.