Sensors, Vol. 20, Pages 6480: Estimating Position from Millisecond Samples of GPS Signals (the “FastFix” Algorithm)

Sensors, Vol. 20, Pages 6480: Estimating Position from Millisecond Samples of GPS Signals (the “FastFix” Algorithm)
Sensors doi: 10.3390/s20226480
Authors:
Timothy C. A. Molteno

A new approach to GPS positioning is described in which the post-processing of ultra-short sequences of captured GPS signal data can produce an estimate of receiver location. The algorithm, called ‘FastFix’, needs only 2–4 ms of stored L1-band data sampled at ∼16 MHz. The algorithm uses a least-squares optimization to estimate receiver position and GPS time from measurements of the relative codephase, and Doppler-shift of GNSS satellite signals. A practical application of this algorithm is demonstrated in a small, lightweight, low-power tracking tag that periodically wakes-up, records and stores 4 ms of GPS L1-band signal and returns to a low-power state—reducing power requirements by a factor of ∼10,000 compared to typical GPS devices. Stationary device testing shows a median error of 27.7 m with a small patch antenna. Results from deployment of this tag on adult Royal Albatross show excellent performance, demonstrating lightweight, solar-powered, long-term tracking of these remarkable birds. This work was performed on the GPS system; however, the algorithm is applicable to other GNSS systems.

Source: Sensors - November 13, 2020 Category: Biotechnology Authors: Timothy C. A. Molteno Tags: Letter Source Type: research