For developing a free radical-quenched surface-enhanced Raman scattering (SERS) probe, starch, a linear molecule, was used as a protective layer to coat gold nanoshells (GNSs) as enhancement substrates and then, methylene blue (MB) was absorbed on the starch-coated GNSs as a free radical-responsive element. By detecting the change of the SERS intensity of MB on GNSs, the free radical-quenched S...

The extreme weakness of global navigation satellite system (GNSS) signals makes them vulnerable to almost every kind of interferences that, without adequate countermeasures, can heavily compromise the receiver performance. An effective solution is represented by time-frequency (TF) analysis that has proved to be able to detect and suppress a wide class of disturbing signals. However, high compu...

In this paper, a multirate approach is proposed for the recovery of wide-band (Global Navigation Satellite System) GNSS signals. Two or more narrow-band front-ends are used in parallel for collecting different portions of the spectrum of a wide-band GNSS signal that is then reconstructed from its subband components. Algorithms for compensating for phase offsets and amplitude imbalances have bee...

Real-time Precise Point Positioning (PPP) technique is being widely applied for providing precise positioning services with the significant improvement on satellite precise products accuracy. With the rapid development of the multi-constellation Global Navigation Satellite Systems (multi-GNSS), currently, about 80 navigation satellites are operational in orbit. Obviously, PPP performance is dra...

In this paper, a novel range compression algorithm for enhancing range resolutions of a passive Global Navigation Satellite System-based Synthetic Aperture Radar (GNSS-SAR) is proposed. In the proposed algorithm, within each azimuth bin, firstly range compression is carried out by correlating a reflected GNSS intermediate frequency (IF) signal with a synchronized direct GNSS base-band signal in...

Falsifying Global Navigation Satellite System (GNSS) data with a simulator or with a fake receiver can have a significant economic or safety impact in many transportation applications where Position, Velocity and Time (PVT) are used to enforce a regulation. In this context, the authentication of the source of the PVT data (i.e., the GNSS receiver) is a requirement since data faking can become a...

The key limitation of existing Real-Time Kinematic (RTK) systems is the service distances between reference stations and user receivers due to the impact of distance-dependent biases such as orbit error, and ionospheric and tropospheric signal delay. In current Network-RTK implementations, the inter-station distance is typically 70km to 90km. If coverage were to be extended to the whole Queensl...

Geofences are virtual boundaries based on geographic coordinates. When combined with global position system (GPS), or more generally global navigation satellite system (GNSS) transmitters, geofences provide a powerful tool for monitoring the location and movements of objects of interest through proximity alarms. However, the accuracy of geofence alarms in GNSS-radio frequency (GNSS-RF) transmit...

Recent advances in the US GPS constellation have resulted in additional signals being made available for both military and civil applications. The modernized GPS signal structure now includes signals broadcast on three frequencies with both the legacy GPS modulation codes, additional civilian codes, and also additional military codes on L1 and L2. In the next few years, GNSS users will also be ...