Single antenna null-steering for GPS & GNSS aerial applications
- As the utility of the Global Positioning System (GPS) and other Global Navigation Satellite Systems (GNSS) continue to pervade -and upgrade- our daily activities, our increased reliance makes us more vulnerable to the inherent weaknesses of GPS. The incredible faintness and unencrypted nature of the GNSS signal exposes it to both unintentional and intentional overwhelming, via mechanisms such as interference, jamming and spoofing (the broadcast of counterfeit GNSS signals intended to deceive a GNSS receiver). However some may argue that despite the great risk, the probability of a jamming or spoofing event is thankfully low. The argument may continue, that correspondingly few resources should be dedicated to protect against a low probability event. I attempt to resolve the tension between these high risk yet low probability scenarios by establishing antenna designs that provide protection while exploiting existing infrastructure and equipment, thus requiring minimal additional resource dedication. This thesis will start with an introduction of a low complexity mechanism for generating radiation pattern nulls and beams with a single antenna, without requiring any additional hardware or signal processing blocks beyond those already inherent to GNSS receiver systems. I will describe the basic mathematical model that underlies this mechanism and share simulation results. I will then introduce two applications of this mechanism: single antenna interference/jam suppression and single antenna spoof detection. Results from simulations and two field trials will be presented: one with a software implementation using a software defined radio, and the other with a hardware prototype implemented in off-the-shelf components using a standard GPS receiver. Results show about 15 dB of interference/jam suppression and robust spoof detection, when the threatening signals originate from below the horizon of the GNSS antenna, making aerial platforms an ideal application.
|Type of resource
|electronic; electronic resource; remote
|1 online resource.
|Stanford University, Department of Electrical Engineering.
|Statement of responsibility
|Submitted to the Department of Electrical Engineering.
|Thesis (Ph.D.)--Stanford University, 2016.
- © 2016 by Emily Beth McMilin
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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