GNSS GPS Research Articles

Assessment of the possible impact on the safety of civil navigation of existing concepts of «navigation pressure»

The features of the global satellite GNSS GPS, as originally a system for military purposes, are considered. The experience of its combat use in recent military conflicts, including during a special military operation, is summarized. Numerous failures in the reception of GPS signals by civilian users, including air carriers and navigators, have been identified when operating GPS in a military environment. The main provisions of the concept of navigation warfare adopted in the United States, one of the elements of which is GNSS GPS and the main goals that it pursues, are considered. An assessment was made of the possible impact of the provisions of the navigational war on the safety of civil navigation and the main directions of work to minimize this impact were outlined. The increasing role and place of nautical astronomy is indicated, as a completely autonomous means of navigation, suitable for use in any area of the World Ocean.

Accessibility of Urban Forests and Parks for People with Disabilities in Wheelchairs, Considering the Surface and Longitudinal Slope of the Trails

This research deals with the problem of the accessibility of urban forests and parks for people with disabilities in wheelchairs. Through an analysis of spatial data, trails were categorized on the basis of the measurements of the independent movements of eight subjects on six trails. The critical longitudinal slopes were determined for independent movement in wheelchairs, complex independent movement with certain risk, and categories of trails that are not suitable for wheelchair movement. The results indicate that a slope of 5.50% was the tipping point, after which all respondents experienced some uncertainty. In addition, a gradient of more than 9.01% was almost impassable for people in wheelchairs, with respect to the gravel trails examined in this study. Modern measurement technology was used in the field, including the mobile apps GAIA GPS and GNSS GPS, and a total (geodetic) station; the subjects’ heart rates were measured using a Garmin Fenix 6 Pro watch. In addition, people with disabilities were included in the implementation of the research through the Croatian Association of Paraplegics and Tetraplegics (HUPT). The results indicate the zones/trails that disabled people in wheelchairs can pass independently, the zones that can be accessed with a certain risk, and those that are not accessible, all according to the defined longitudinal slope zones using measurements of the movement of people in a wheelchair, their heart rate loads, and personal communication with the subjects regarding the insecurity they felt.

Evening time multi-instrumental verification of ionospheric irregularity in East Africa, Ethiopia

This study verifies ionospheric irregularity and its associated scintillation using five independent observations during June solstice and September equinox, 2014 over the understudied and data scarce East African longitude sector. Simultaneous measurements of ionospheric irregularity through Communication and Navigation Outage Forcasting System (C/NOFS), Scintillation Networks and Decision Aid (SCINDA) GPS receivers, Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC), GNSS GPS, VHF dedicated beacon receivers as well as ionosonde were carried out in the region. C/NOFS has detected prereversal enhancement (PRE, the most accepted trigger of equatorial spread F (ESF)) at ~19:00 LT during September equinox and at ~20:00 LT for June solstice. The PRE detection during June is further confirmed by the ionosonde derived uplift movement of hmF2 over the region. Rate of change of TEC index (ROTI) is also found to be capable of capturing the evening time ionospheric irregularities in a way consistent to the dedicated scintillation measuring instruments regardless of the spatial difference between the two GNSS GPS sites in East Africa. Overall, throughout the in situ and ground-based ionospheric irregularity measurements, extreme scintillation starts to occur at around 19:00 LT and continued until midnight. Besides, the power spectral density (PSD) was computed using the Fast Fourier Transform (FFT) algorithm for S4 data measured while receiving L-band and VHF signals as well as while measuring C/NOFS ion density. Upon the captured strength of ionospheric irregularity, the noisy portion of frequency on PSD is wider in VHF and C/NOFS driven irregularity index than the corresponding L-band irregularity observation. Most importantly the calculated slope (m) and the strength of irregularity (β) using the power spectral law has enabled us to produce a model which better fits the observed spectrum. It was also found that the PSD theoretical modeling better matches for L-band than VHF and Ni spectral observation.

Walanae Fault Kinematic Deduced from Geometric Geodetic GNSS GPS Monitoring

The western Sulawesi region has the main structural boundary, the Palu Koro Fault which divides from Palu Bay at the northest part to Central Sulawesi and continues into the Bone Gulf in southest part. In the southern part of this region, namely the South Sulawesi Arm zone, there is a Walanae fault which is defined as a sinistral wrench with a NW-SE direction that divides the South Arm of Sulawesi. This fault in the northern part is expected to continue to the northwest intersecting the Makassar Strait and unite with Paternoster-Lupar (Kalimantan) sutures and at the southest ending in Flores thrust fault. Walanae fault system did not only have one strand but was divided into 4 parts, namely the northern East Walanae Fault with a slip rate of 6.634 mm/year and the southern part with a 7.097 mm/year of slip rate, as well as the northern part of West Walanae Fault with a slip rate of 4.528 mm/year and the southern part with a slip rate of 3.270 mm/year. The northern part of Walanae fault system has opening or spreading pattern occurs that is in harmony with the formation of Walanae depression. By using simple geometric modeling, we found the fault system have 2 strain partitions with dominant sinistral strike slip pattern at southern part and combination between left lateral strike slip with thrust fault pattern at northern part.

Regional Phenomena of Vertical Deformation in Southern Part of Indonesia

Distribution of present-day horizontal and vertical deformation across the Southern Part of Indonesia at Java, Bali and Nusa Tenggara now days can be determined from continuous and campaign types of GNSS GPS data monitoring. For vertical deformation in this case we use the continuous types since they are give better quality of data consistency compare to campaign type. Continuous Global Positioning System (CGPS) are maintaining by Geospatial Information Agency for more than a decade. The vertical displacements or velocity rates are estimated from time series analysis after multi-baseline GPS processing using GAMIT-GLOBK software with respect to the latest International Terrestrial Reference Frame. The result shows some interesting phenomena where the northern part of research area majority have negative value that may indicate land subsidence with or without tectonic subsidence combination. In the middle part, the uplift phenomena are clearly shown and in the southern part show combine pattern between uplift and subsidence. The impacts of those phenomena would be discuss also in this paper since many population and infrastructure are located in the areas that will need more protection planning to reduce the negative impact such as earthquake and flooding.

IESID: Automatic system for monitoring ground deformation on the Deception Island volcano (Antarctica)

When establishing the relative distance between two GNSS–GPS stations with sub-centimeter accuracy, it is necessary to have auxiliary data, some of which can only be collected some time after the moment of measurement.However, for monitoring highly-active geodynamic areas, such as volcanoes and landslides, data precision is not as essential as rapid availability, processing of data in real-time, and fast interpretation of the results.This paper describes the development of an integrated automatic system for monitoring volcanic deformation in quasi real-time, applied to the Deception volcano (Antarctica). This experimental system integrates two independent modules that enable researchers to monitor and control the status of the GNSS–GPS stations, and to determine a surface deformation parameter. It comprises three permanent stations, one of which serves as the reference for assessing the relative distance in relation to the other two. The availability of GNSS–GPS data in quasi real-time is achieved by means of a WiFi infrastructure and automated data processing. This system provides, in quasi real-time, a time series of varying distances that tells us the extent to which any ground deformation is taking place.

Kinematic model for Tenerife Island (Canary Islands, Spain): Geodynamic interpretation in the Nubian plate context

Establishment of a geodetic network in Tenerife is the starting point for the use of GPS and other precise geodetic techniques in the support of the study of kinematics and their relation with island volcanic activity. This paper is focused on the characterization of volcanotectonic activity of Tenerife, to determine the geodynamic framework for volcanic surveillance. TEGETEIDE network, set up in 2005 and re-observed each year, is composed of seven GNSS–GPS stations scattered throughout the island. A horizontal deformation model is presented in order to explain the observed island displacement pattern in the geodynamic context of the Nubian plate. According to the models obtained, the most important geologic structures, such as the volcanic rifts and the caldera, determine the current deformation pattern of Tenerife. The geodynamics of the most stable areas of the island behave similarly to that observed from the permanent GNSS–GPS reference stations located in La Palma and Gran Canaria Islands. Anomalous geodynamic behaviour has been detected in two zones of Tenerife, which configure an NW–SE axis crossing the central sector of the island, related with the volcanotectonic activity of the island and its surroundings.