ABSTRACT The Chapter begins with a discussion of currently available wildlife tracking systems an... more ABSTRACT The Chapter begins with a discussion of currently available wildlife tracking systems and explains why tag mass is the primary design constraint. Current manual direction-finding methods are described, as are several automated implementations. We also discuss the need for generic asset (nonwildlife) tracking tags that are light and inexpensive, and review current asset tracking methods based on cellular and satellite platforms in this context. The shortcomings of existing systems motivate the need for a new approach that offers global positioning system (GPS)-like accuracy, with vastly reduced energy consumption. Terrestrial time-of-arrival (TOA) tracking methods are discussed as a lower energy cost solution, with specific sections dedicated to explaining the following concepts and their interplay in an integrated system: code division multiple access (CDMA), matched filtering, estimating location with TOA, and efficient signal processing via digital signal processor (DSP). The section on CDMA and matched filtering introduces basic concepts including spectrum utilization, autocorrelation, cross correlation, signal-to-noise ratio (SNR), link budget, and processing gain. The TOA section describes several different approaches to calculating location from arrival-time measurements, including the estimation methods employed by GPS, the canonical crossed spheres or hyperboloid techniques, and a method that we developed based on stochastic spatial search. We compare the performance of these methods using real and simulated data. The signal processing section details the computational requirements of real-time matched filtering, including the impact of Doppler shift. We describe several techniques used in order to implement real-time TOA receivers in embedded devices with limited computing resources, including the use of frequency domain processing via fast Fourier transform (FFT), and the intelligent reuse of data via time-shifting techniques. The chapter concludes with a summary of the current performance of a TOA wildlife tracking system that we implemented, its design limitations, and likely areas for improvement.
... data. - Capture test responses into Lls with C1. - Establish the Scan State and unload (A/B c... more ... data. - Capture test responses into Lls with C1. - Establish the Scan State and unload (A/B clocks) the responses. ... Format Faults in the Logic Between L2s and Lls Most transition faults in simple double-latch designs are in this category. ...
ABSTRACT The Chapter begins with a discussion of currently available wildlife tracking systems an... more ABSTRACT The Chapter begins with a discussion of currently available wildlife tracking systems and explains why tag mass is the primary design constraint. Current manual direction-finding methods are described, as are several automated implementations. We also discuss the need for generic asset (nonwildlife) tracking tags that are light and inexpensive, and review current asset tracking methods based on cellular and satellite platforms in this context. The shortcomings of existing systems motivate the need for a new approach that offers global positioning system (GPS)-like accuracy, with vastly reduced energy consumption. Terrestrial time-of-arrival (TOA) tracking methods are discussed as a lower energy cost solution, with specific sections dedicated to explaining the following concepts and their interplay in an integrated system: code division multiple access (CDMA), matched filtering, estimating location with TOA, and efficient signal processing via digital signal processor (DSP). The section on CDMA and matched filtering introduces basic concepts including spectrum utilization, autocorrelation, cross correlation, signal-to-noise ratio (SNR), link budget, and processing gain. The TOA section describes several different approaches to calculating location from arrival-time measurements, including the estimation methods employed by GPS, the canonical crossed spheres or hyperboloid techniques, and a method that we developed based on stochastic spatial search. We compare the performance of these methods using real and simulated data. The signal processing section details the computational requirements of real-time matched filtering, including the impact of Doppler shift. We describe several techniques used in order to implement real-time TOA receivers in embedded devices with limited computing resources, including the use of frequency domain processing via fast Fourier transform (FFT), and the intelligent reuse of data via time-shifting techniques. The chapter concludes with a summary of the current performance of a TOA wildlife tracking system that we implemented, its design limitations, and likely areas for improvement.
... data. - Capture test responses into Lls with C1. - Establish the Scan State and unload (A/B c... more ... data. - Capture test responses into Lls with C1. - Establish the Scan State and unload (A/B clocks) the responses. ... Format Faults in the Logic Between L2s and Lls Most transition faults in simple double-latch designs are in this category. ...
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Papers by Rich Gabrielson