Context aware high dynamics gnss-ins for interference mitigation
Date
2011
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Abstract
Autonomous navigation systems used in missiles are mostly dependent on Global Positioning System (GPS) as a primary means of navigation. GPS usage has limitations in terms of missile high dynamics and expected signal interference in the battlefield. Due to the conflicting bandwidth requirements in Phase/ Frequency Lock Loops (PLLs/ FLLs), a novel FLL-assisted-PLL is proposed for very high dynamic conditions with reduced measurement noise and capabilities to cope with interference. The design is based on fuzzy systems and is used to generate the required Numerical Control Oscillator (NCO) tuning frequency with the information provided by phase and frequency discriminators. Detailed system design and performance analysis are presented where scenarios include high dynamics and different types and levels of interference are introduced. The designed system is compared also against 3rd order PLLs, with narrow and wide bandwidths, standard FLL-assisted-PLL, in addition to a Kalman Filter (KF) based PLL. Moreover, to insure robustness of the new system during periods of GPS blockage due to very high interference levels, the system is integrated with additional aiding that can provide external Doppler measurements. Two approaches are introduced to accomplish this. The first approach is to use the measurements available from the missile Inertial Measurement Unit (IMU) as these are not affected by interference. The second approach is to get the benefit from the modem GPS signals such as L2C signal which can be assumed not to be affected by interference if a narrow band interference signal is aimed at the primary GPS signal L 1. Performance assessments results demonstrate the enhanced performance of the proposed system where better tracking continuity during high dynamics up to 20 g's of acceleration and more accurate measurements in interference free environments and in low and medium interference levels up to jamming-to-signal ratios of 40 dB are achieved for the stand alone system, and at very high interference levels for the aided system.
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Bibliography: p. 193-199
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Citation
Kamel, A. M. (2011). Context aware high dynamics gnss-ins for interference mitigation (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/4461