scholarly journals Development and Implementation of the Robot Prototype with Inertial Navigation for Work in the Arctic

2019 ◽  
Vol 8 (4) ◽  
pp. 4584-4590
Keyword(s):  
Navigation System ◽  
Rapid Development ◽  
Access Point ◽  
Global Navigation Satellite Systems ◽  
Wireless Access ◽  
The Arctic ◽  
Satellite Systems ◽  
Determination Error ◽  
Micromechanical Sensors ◽  
Global Navigation Satellite

Currently, there is a very rapid development of robotics. People use robots in many areas of their activities. Especially valuable is the use of robots in hazardous conditions for humans, in particular in studies in the Arctic. In this case, there is an acute problem of navigation. The use of global navigation satellite systems (GNSS) in the Arctic is difficult due to the small number of satellites and the influence of Aurora. Therefore, we chose the inertial type of navigation for the prototype of the robot. We used LSM330DL micromechanical sensors and Atmega8-16AU microcontroller to create a navigation system. We used wireless access point Ubiquiti Bullet M2HP Titanium to connect the robot with researchers. Tests of a prototype of a robot on a wheeled platform showed that the coordinate determination error does not exceed 6%. Tests of the navigation system were carried out up to -20°C. System components allow operation up to -40°C. The proposed navigation system can be used to create robots for work in the Arctic.

Geolocal – A New System for Geo-Referencing: Analysis of Base Distribution

2020 ◽  
pp. 1-13
Author(s):  
Eduardo P. Macho ◽  
Sergio V.D. Pamboukian ◽  
Emília Correia
Keyword(s):  
Time Delay ◽  
Navigation System ◽  
Measurement Errors ◽  
Global Navigation Satellite Systems ◽  
Navigation Satellite ◽  
Dilution Of Precision ◽  
Satellite Systems ◽  
Global Navigation ◽  
Global Navigation Satellite ◽  
New System

Geolocal is a new navigation system conceived and patented in Brazil, whose purpose is to be independent of other global navigation satellite systems (GNSS). It has an ‘inverted-GNSS’ configuration with at least four bases on the ground at known geodesic position coordinates and a repeater in space. Simulations were performed to determine the precision of Geolocal using different quantities and distributions of bases. They showed that this precision is enhanced when the quantity of bases increases, as long as the elevation angles of the new bases included are higher than the average and when the bases are evenly distributed around the repeater, but mainly when the time delay at the repeater is known in advance and when the measurement errors that generate uncertainties are reduced. The position dilution of precision (PDOP) was also calculated, confirming that precision is enhanced by the quantity of bases and by their distribution.

Determation of the ionospheric observable and short-term variations of receiver DCBs using modified carrier‑to‑code leveling method with multi-frequency and multi-GNSS data

2020 ◽  
Author(s):  
Min Li ◽  
Baocheng Zhang ◽  
Xiao Zhang
Keyword(s):  
Rapid Development ◽  
Full Rank ◽  
Global Navigation Satellite Systems ◽  
Dual Frequency ◽  
Short Term ◽  
Frequency Model ◽  
Satellite Systems ◽  
Triple Frequency ◽  
Global Navigation Satellite ◽  
Gnss Data

<p>When sensing the Earth’s ionosphere using pseudorange observations of global navigation satellite systems (GNSS), the satellite and receiver Differential Code Biases (DCBs) account for one of the main sources of error. For the sake of convenience, Receiver DCBs (DCBs) are commonly assumed as constants over a period of one day in the traditional carrier-to-code leveling (CCL) method. Thus, remarkable intraday variability in the receiver DCBs have been ignored in the commonly-used assumption and may seriously restrict the accuracy of ionospheric observable retrieval. The Modified CCL (MCCL) method can eliminate the adverse impact of the short-term variations of RDCBs on the retrieval of ionospheric TEC. With the rapid development of the GPS, GLONASS, Galileo and BeiDou systems, there is a strong demand of precise ionospheric TEC products for multiple constellations and frequencies. Considering the existed MCCL method can only be used for dual-frequency GNSS data, in this study, we extend the two-frequency MCCL method to the multi-frequency and multi-GNSS case and further carry out a series of investigations. In our proposed method, a newly full-rank multi-frequency (more than triple frequency) model with raw observations are established to synchronously estimate both the slant ionospheric delays and the RCB offset with respect to the reference epoch at each individual frequency. Based on the test results, compared to the traditional CCL-method, the accuracy of the ionospheric TEC retrieved using our proposed method can be improved from 5.12 TECu to 0.95 TECu in the case that significant short-term variations existed in receiver DCBs. In addition, the between-epoch fluctuations experienced by receiver code biases at all frequencies tracked by a single receiver can be detected by our the proposed method, and the dependence of multi-GNSS and multi-frequency RDCB offsets upon ambient temperature further are verified in this study. Compared to Galileo system, the RDCB in BDS show higher correlation with temperature. We also found that the RDCB at different frequencies of the same system show various characteristics.</p>

scholarly journals Seamless Indoor-Outdoor Navigation based on GNSS, INS and Terrestrial Ranging Techniques

2017 ◽  
Vol 70 (6) ◽  
pp. 1183-1204 ◽  
Author(s):  
Wei Jiang ◽  
Yong Li ◽  
Chris Rizos ◽  
Baigen Cai ◽  
Wei Shangguan
Keyword(s):  
Navigation System ◽  
Global Navigation Satellite Systems ◽  
Indoor Environments ◽  
Integrated Navigation ◽  
Satellite Systems ◽  
Integrated Navigation System ◽  
Outdoor Environments ◽  
Federated Kalman Filter ◽  
Indoor And Outdoor Environments ◽  
Global Navigation Satellite

We describe an integrated navigation system based on Global Navigation Satellite Systems (GNSS), an Inertial Navigation System (INS) and terrestrial ranging technologies that can support accurate and seamless indoor-outdoor positioning. To overcome severe multipath disturbance in indoor environments, Locata technology is used in this navigation system. Such a “Locata-augmented” navigation system can operate in different positioning modes in both indoor and outdoor environments. In environments where GNSS is unavailable, e.g. indoors, the proposed system is designed to operate in the Locata/INS “loosely-integrated” mode. On the other hand, in outdoor environments, all GNSS, Locata and INS measurements are available, and all useful information can be fused via a decentralised Federated Kalman filter. To evaluate the proposed system for seamless indoor-outdoor positioning, an indoor-outdoor test was conducted at a metal-clad warehouse. The test results confirmed that the proposed navigation system can provide continuous and reliable position and attitude solutions, with the positioning accuracy being better than five centimetres.

scholarly journals UAVS ENHANCED NAVIGATION IN OUTDOOR GNSS DENIED ENVIRONMENT USING UWB AND MONOCULAR CAMERA SYSTEMS

2019 ◽  
Vol XLII-2/W13 ◽  
pp. 665-672 ◽  
Author(s):  
S. Zahran ◽  
A. Masiero ◽  
M. M. Mostafa ◽  
A. M. Moussa ◽  
A. Vettore ◽  
...  
Keyword(s):  
Navigation System ◽  
Low Cost ◽  
Global Navigation Satellite Systems ◽  
Ultra Wideband ◽  
Measurement Unit ◽  
Satellite Systems ◽  
Monocular Camera ◽  
Camera Systems ◽  
Global Navigation Satellite ◽  
The Cost

<p><strong>Abstract.</strong> The demand for small Unmanned Aerial Vehicles (UAVs) is massively increasing these days, due to the wide variety of applications utilizing such vehicles to perform tasks that may be dangerous or just to save time, effort, or cost. Small UAVs navigation system mainly depends on the integration between Global Navigation Satellite Systems (GNSS) and Inertial Measurement Unit (INS) to estimate the Positions, Velocities, and Attitudes (PVT) of the vehicle. Without GNSS such UAVs cannot navigate for long periods of time depending on INS alone, as the low-cost INS typically exhibits massive accumulation of errors during GNSS absence. Given the importance of ensuring full operability of the UAVs even during GNSS signals unavailability, other sensors must be used to bound the INS errors and enhance the navigation system performance. This paper proposes an enhanced UAV navigation system based on integration between monocular camera, Ultra-Wideband (UWB) system, and INS. In addition to using variable EKF weighting scheme. The paper also investigates this integration in the case of low density of UWB anchors, to reduce the cost required for such UWB system infrastructure. A GoPro Camera and UWB rover were attached to the belly of a quadcopter, an on the shelf commercial drone (3DR Solo), during the experimental flight. The velocity of the vehicle is estimated with Optical Flow (OF) from camera successive images, while the range measurements between the UWB rover and the stationary UWB anchors, which were distributed on the field, were used to estimate UAV position.</p>

scholarly journals A Chip Scale Atomic Clock Driven Receiver for Multi-Constellation GNSS

2013 ◽  
Vol 66 (3) ◽  
pp. 449-464 ◽  
Author(s):  
Alper Ucar ◽  
Yacine Adane ◽  
Burak Bardak ◽  
Carlo Paparo ◽  
Reuben Berry ◽  
...  
Keyword(s):  
Rapid Development ◽  
Atomic Clock ◽  
Global Navigation Satellite Systems ◽  
Dual Band ◽  
Easy Access ◽  
Signal Acquisition ◽  
Multipath Mitigation ◽  
Satellite Systems ◽  
Dual Channel ◽  
Global Navigation Satellite

This paper presents the design and implementation of a Chip Scale Atomic Clock (CSAC) driven dual-channel Digitally Configurable Receiver (DCR) for Global Navigation Satellite Systems (GNSS). The receiver is intended to be used for research applications such as; multipath mitigation, scintillation assessment, advanced satellite clock and spatial frame transformation modelling, Precise Point Positioning (PPP) as well as rapid development and assessment of novel circuits and systems for GNSS receivers. A novel sub-Nyquist sampling (subsampling) receiver architecture incorporating dual-band microstrip RF filters is employed in order to minimize the complexity of the multi-frequency Radio Frequency (RF) front-end. Moreover, the digital receiver incorporates a novel and complexity-reduced Fast Fourier Transform (FFT) core for signal acquisition as well as COordinate Rotation DIgital Computer (CORDIC) cores for the code/carrier discriminators in order to minimize the resource allocation on the FPGA. The receiver also provides easy access to enable adjustment of its internal parameters such as; RF gain, position update rate, tracking channel correlator spacing and code/carrier loop noise bandwidth. Correlator outputs, code/carrier error, Carrier-to-Noise Ratio (C/N0), navigation and RINEX data are provided to the end-user in real-time. This paper collectively highlights and reports on the implementation, test and validation of the novel techniques, elements and approaches in both the RF and digital part of the DCR that comprise the multi-constellation receiver.

Ionosphere VTEC modeling with the raw-observation-based PPP model：an advantage demonstration in the multi-frequency and multi-GNSS context

2020 ◽  
Author(s):  
Teng Liu ◽  
Baocheng Zhang ◽  
Yunbin Yuan ◽  
Xiao Zhang
Keyword(s):  
Rapid Development ◽  
Global Navigation Satellite Systems ◽  
Electron Content ◽  
Vertical Total Electron Content ◽  
Dual Frequency ◽  
International Gnss Service ◽  
Total Electron ◽  
Satellite Systems ◽  
Triple Frequency ◽  
Global Navigation Satellite

&lt;p&gt;The ionospheric delay accounts for one of the major errors that the Global Navigation Satellite Systems (GNSS) suffer from. Hence, the ionosphere Vertical Total Electron Content (VTEC) map has been an important atmospheric product within the International GNSS Service (IGS) since its early establishment. In this contribution, an enhanced method has been proposed for the modeling of the ionosphere VTECs. Firstly, to cope with the rapid development of the newly-established Galileo and BeiDou constellations in recent years, we extend the current dual-system (GPS/GLONASS) solution to a quad-system (GPS/GLONASS/Galileo/BeiDou) solution. More importantly, instead of using dual-frequency observations based on the Carrier-to-Code Leveling (CCL) method, all available triple-frequency signals are utilized with a general raw-observation-based multi-frequency Precise Point Positioning (PPP) model, which can process dual-, triple- or even arbitrary-frequency observations compatibly and flexibly. Benefiting from this, quad-system slant ionospheric delays can be retrieved based on multi-frequency observations in a more flexible, accurate and reliable way. The PPP model has been applied in both post-processing global and real-time regional VTEC modeling. Results indicate that with the improved slant ionospheric delays, the corresponding VTEC models are also improved, comparing with the traditional CCL method.&lt;/p&gt;

scholarly journals Drones and global navigation satellite systems: current evidence from polar scientists

2020 ◽  
Vol 7 (3) ◽  
pp. 191494 ◽  
Author(s):  
Iain Sheridan
Keyword(s):  
Strong Relationship ◽  
Specific Pattern ◽  
Unmanned Vehicles ◽  
Global Navigation Satellite Systems ◽  
The Arctic ◽  
Current Evidence ◽  
Navigation Satellite ◽  
Satellite Systems ◽  
Global Navigation ◽  
Global Navigation Satellite

Aerial unmanned vehicles, so-called drones, present a paradigm shift away from the long-term use by scientists of manned aeroplanes and helicopters. This is evident from the number of research articles that focus on data obtained with drones. This article examines the use of aerial drones for scientific research in cryospheric regions, especially Antarctica and the Arctic. Specifically, it aims to provide insights into the choices and performance of global navigation satellite systems (GNSS) use for drones, including augmentation systems. Data on drone GNSS navigation and positioning in the context of scientific polar research have been scarce. Drone survey data obtained from polar scientists in April 2019 is the first representative sample from this close-knit global community across the specialisms of climatology, ecology, geology, geomorphology, geophysics and oceanography. The survey results derived from 16 countries revealed that 14.71% of scientists used GALILEO, 27.94% used GLONASS and 45.59% used GPS. Many used a combination of two or more GNSS. Multiple regression analysis showed that there is no strong relationship between a specific pattern of GNSS augmentation and greater positioning accuracy. Further polar drone studies should assess the effects of phase scintillation on all GNSS, therefore BEIDOU, GALILEO, GLONASS and GPS.

scholarly journals LEO Constellation-Augmented Multi-GNSS for 3D Water Vapor Tomography

2021 ◽  
Vol 13 (16) ◽  
pp. 3056
Author(s):  
Si Xiong ◽  
Fujian Ma ◽  
Xiaodong Ren ◽  
Jun Chen ◽  
Xiaohong Zhang
Keyword(s):  
Water Vapor ◽  
Rapid Development ◽  
Three Dimensional ◽  
Horizontal Resolution ◽  
Observation Time ◽  
Low Earth Orbit ◽  
Global Navigation Satellite Systems ◽  
Satellite Systems ◽  
Dimensional Distribution ◽  
Global Navigation Satellite

Global navigation satellite systems (GNSS) water vapor tomography is an important technique to obtain the three-dimensional distribution of atmospheric water vapor. The rapid development of low Earth orbit (LEO) constellations has led to a richer set of observations, which brings new expectations for water vapor tomography. This paper analyzes the influence of LEO constellation-augmented multi-GNSS（LCAMG）on the tomography, in terms of ray distribution, tomography accuracy, and horizontal resolution, by simulating LEO constellation data. The results show that after adding 288 LEO satellites to GNSS, the 30-min ray distribution effect of GNSS can be achieved in 10 min, which can effectively shorten the observation time by 66.7%. In the 10-min observation time, the non-repetitive effective observation value of LCAMG is 2.38 times that of GNSS, and the accuracy is 1.27% higher than that of GNSS. Compared with GNSS and the global positioning system (GPS), at a horizontal resolution of 13 × 14, the proportion of empty voxels in LCAMG reduces by 5.22% and 22.53%, respectively.

Sea Ice Classification and Altimetry using Grazing Angle Reflected GNSS Signals Measured by Spire’s Nanosatellite Constellation

2021 ◽  
Author(s):  
Jessica Cartwright ◽  
Vu Nguyen ◽  
Philip Jales ◽  
Oleguer Nogues-Correig ◽  
Takayuki Yuasa ◽  
...  
Keyword(s):  
Sea Ice ◽  
Weather Prediction ◽  
Grazing Angle ◽  
Surface Characteristics ◽  
Global Navigation Satellite Systems ◽  
Ice Age ◽  
The Arctic ◽  
Satellite Systems ◽  
Global Navigation Satellite ◽  
The Antarctic

&lt;p&gt;Global Navigation Satellite Systems-Reflectometry (GNSS-R) offers novel observations over the cryosphere with the use of reflected navigation signals (eg. GPS or Galileo) as signals of opportunity. This technique has the potential for higher resolution measurements over sea ice than routinely acquired by passive microwave systems with a footprint of around 5 km2 and is much lower in power consumption, mass and therefore cost. Here we present sea ice classification and altimetry as observed at grazing angles by Spire&amp;#8217;s Radio Occultation (RO) Satellite constellation, repurposed for GNSS-R.&lt;/p&gt;&lt;p&gt;The Spire RO constellation of 37 operational satellites (and growing) is relied upon to support critical numerical weather prediction and has been collecting GNSS signals as they refract through the atmosphere. The reprogramming of these satellites to receive signals reflected at grazing angle allows these signals to instead inform on Earth surface characteristics. From smooth surfaces, these signals are phase coherent at L-Band frequencies (~19 - 24 cm wavelength) and allow the detection of the roughness of the sea ice in addition to the height of the surface to several centimetres of precision. Three months of these operational sea ice detection and classification products are presented from Spring of 2020; with ice extent in agreement with external passive and active sources to around 98% in the Antarctic and 94% in the Arctic, and ice age classification (First Year/Multi-Year) agreeing in the Arctic to around 70%. First results are shown for the potential to detect other ice characteristics such as the Antarctic Marginal Ice Zone extent and floe size / type.&lt;/p&gt;

scholarly journals Selected Issues and Constraints of Image Matching in Terrain-Aided Navigation: A Comparative Study

2020 ◽  
Author(s):  
Piotr Turek ◽  
Stanisław Grzywiński ◽  
Witold Bużantowicz
Keyword(s):  
Navigation System ◽  
Operating Conditions ◽  
Global Navigation Satellite Systems ◽  
Reference Image ◽  
Satellite Systems ◽  
Performance Effectiveness ◽  
Reference Images ◽  
Global Navigation Satellite ◽  
Navigational Systems ◽  
Uav Navigation

The sensitivity of global navigation satellite systems to disruptions precludes their use in conditions of armed conflict with an opponent possessing comparable technical capabilities. In military unmanned aerial vehicles (UAVs) the aim is to obtain navigational data to determine the location and correction of flight routes by means of other types of navigational systems. To correct the position of an UAV relative to a given trajectory, the systems that associate reference terrain maps with image information can be used. Over the last dozen or so years, new, effective algorithms for matching digital images have been developed. The results of their performance effectiveness are based on images that are fragments taken from source files, and therefore their qualitatively identical counterparts exist in the reference images. However, the differences between the reference image stored in the memory of navigation system and the image recorded by the sensor can be significant. In this paper modern methods of image registration and matching to UAV position refinement are compared, and adaptation of available methods to the operating conditions of the UAV navigation system is discussed.

Sign in / Sign up

Export Citation Format

Share Document