Performance Enhancements of GPS User Equipment

Hemesath, N. B.

doi:10.1002/j.2161-4296.1978.tb01330.x

Cited by 9 publications

(5 citation statements)

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“…It corresponds to the ratio of the power level of the carrier signal and the noise level in a 1 Hz bandwidth (Langley 1997). The theoretical carrier phase jitter σ PLL (m) can be approximated by Hemesath (1980) …”

Section: Receiver System Noisementioning

confidence: 99%

Assessment of high-rate GPS using a single-axis shake table

Häberling

Rothacher

Zhang

et al. 2015

J Geod

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The developments in GNSS receiver and antenna technologies, especially the increased sampling rate up to 100 sps, open up the possibility to measure high-rate earthquake ground motions with GNSS. In this paper we focus on the GPS errors in the frequency band above 1 Hz. The dominant error sources are mainly the carrier phase jitter caused by thermal noise and the stress error caused by the dynamics, e.g. antenna motions. To generate a large set of different motions, we used a single-axis shake table, where a GNSS antenna and a strong motion seismometer were mounted with a wellknown ground truth. The generated motions were recorded with three different GNSS receivers with sampling rates up to 100 sps and different receiver baseband parameters. The baseband parameters directly dictate the carrier phase jitter and the correlations between subsequent epochs. A narrow loop filter bandwidth keeps the carrier phase jitter on a low level, but has an extreme impact on the receiver response for motions above 1 Hz. The amplitudes above 3 Hz are overestimated up to 50 % or reduced by well over half. The corresponding phase errors are between 30 and 90 degrees. B S. HäberlingCompared to the GNSS receiver response, the strong motion seismometer measurements do not show any amplitude or phase variations for the frequency range from 1 to 20 Hz. Due to the large errors for dynamic GNSS measurements, it is essential to account for the baseband parameters of the GNSS receivers if high-rate GNSS is to become a valuable tool for seismic displacement measurements above 1 Hz. Fortunately, the receiver response can be corrected by an inverse filter if the baseband parameters are known.

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Section: Receiver System Noisementioning

confidence: 99%

Assessment of high-rate GPS using a single-axis shake table

Häberling

Rothacher

Zhang

et al. 2015

J Geod

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“…A small b value represents a good quality inertial system. A system with b l 0n001 represents roughly the level of CEP performance of today's one nautical mile per hour inertial systems without special calibration (Hemesath, 1980). Even when b is very large, e.g.…”

Section: System Architecture Of the Tracking Loopsmentioning

confidence: 99%

GPS Receiver Performance Enhancement via Inertial Velocity Aiding

Jwo

2001

J. Navigation

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An integrated GPS/INS navigation system can employ inertial velocity information to produce a more robust system. For a stand-alone GPS receiver, decreasing the receiver tracking loop bandwidth reduces the probability of losing lock in a jamming or interference environment if vehicle dynamics are low. However, reduced bandwidth increases tracking errors when dynamics are present. Beyond a certain limit, it causes a serious degradation in the dynamic tracking loop performance. Providing inertial velocity aiding to the receiver tracking loops is an effective and popular treatment to help resolve this problem. In this paper, performance of the GPS receiver tracking loops using inertial velocity aiding will be investigated. Different types of tracking loops, from 1st to 3rd order, are covered. Following the discussion of the system architecture and derivation of the related transfer functions for the tracking loops, both with and without aiding, the system performance, including transient response, steady-state error, and noise bandwidth is evaluated.

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“…Publication Date: November 5, 1994 4, 1980, 1980OJ C 197 Document Date: July 10, 1980 Resolution on the development of a coordinated European air traffic control system…”

Section: Commission Of the European Communitiesmentioning

confidence: 99%