Stand-alone Celestial Navigation Positioning Method

2018 ◽  
Vol 71 (6) ◽  
pp. 1344-1362 ◽  
Author(s):  
Frankiskos Pierros
Keyword(s):  
Satellite System ◽  
Graphical Methods ◽  
Spherical Trigonometry ◽  
Software Application ◽  
Celestial Navigation ◽  
Positioning Method ◽  
Celestial Bodies ◽  
Geographical Position ◽  
Global Navigation Satellite ◽  
Nautical Almanac

Finding one's geographical position (fix) without the use of a Global Navigation Satellite System (GNSS), which was common place before the establishment of the latter, could be tedious and/or inaccurate. Apart from sound knowledge of spherical trigonometry and navigational methods, it also requires the knowledge of the navigator's approximate or assumed position, the use of the current year's celestial bodies' ephemeris (Nautical Almanac), and graphical methods (Lines of Position – LOP) which sometimes can prove wanting in accuracy and/or challenging for the unaccustomed user. The method proposed here is based on sight reduction from two celestial bodies, and directly calculates the geographical position, both for stationary and moving observers (“running fix”) using easily available modern programmable calculating devices, without the need of the assumed position, graphical methods (LOP) or the current year's ephemeris, hence the term “stand-alone”. This self-contained method is implemented by the author in a software application, which can be easily used in a portable computer (for example, a smartphone). The results are considered satisfactorily accurate.

scholarly journals Opportunistic In-Flight INS Alignment Using LEO Satellites and a Rotatory IMU Platform

Aerospace ◽  
2021 ◽  
Vol 8 (10) ◽  
pp. 280
Author(s):  
Farzan Farhangian ◽  
Hamza Benzerrouk ◽  
Rene Landry
Keyword(s):  
Kalman Filter ◽  
State Space Model ◽  
Flight Test ◽  
Satellite System ◽  
Low Earth Orbit ◽  
Measurement Unit ◽  
Starting Point ◽  
Leo Satellites ◽  
Positioning Method ◽  
Global Navigation Satellite

With the emergence of numerous low Earth orbit (LEO) satellite constellations such as Iridium-Next, Globalstar, Orbcomm, Starlink, and OneWeb, the idea of considering their downlink signals as a source of pseudorange and pseudorange rate measurements has become incredibly attractive to the community. LEO satellites could be a reliable alternative for environments or situations in which the global navigation satellite system (GNSS) is blocked or inaccessible. In this article, we present a novel in-flight alignment method for a strapdown inertial navigation system (SINS) using Doppler shift measurements obtained from single or multi-constellation LEO satellites and a rotation technique applied on the inertial measurement unit (IMU). Firstly, a regular Doppler positioning algorithm based on the extended Kalman filter (EKF) calculates states of the receiver. This system is considered as a slave block. In parallel, a master INS estimates the position, velocity, and attitude of the system. Secondly, the linearized state space model of the INS errors is formulated. The alignment model accounts for obtaining the errors of the INS by a Kalman filter. The measurements of this system are the difference in the outputs from the master and slave systems. Thirdly, as the observability rank of the system is not sufficient for estimating all the parameters, a discrete dual-axis IMU rotation sequence was simulated. By increasing the observability rank of the system, all the states were estimated. Two experiments were performed with different overhead satellites and numbers of constellations: one for a ground vehicle and another for a small flight vehicle. Finally, the results showed a significant improvement compared to stand-alone INS and the regular Doppler positioning method. The error of the ground test reached around 26 m. This error for the flight test was demonstrated in different time intervals from the starting point of the trajectory. The proposed method showed a 180% accuracy improvement compared to the Doppler positioning method for up to 4.5 min after blocking the GNSS.

Astronomical Vessel Position Determination Utilizing the Optical Super Wide Angle Lens Camera

2014 ◽  
Vol 67 (4) ◽  
pp. 633-649 ◽  
Author(s):  
Chong-hui Li ◽  
Yong Zheng ◽  
Chao Zhang ◽  
Yu-Lei Yuan ◽  
Yue-Yong Lian ◽  
...  
Keyword(s):  
Autonomous Navigation ◽  
Estimation Method ◽  
Global Navigation Satellite Systems ◽  
Satellite Systems ◽  
Celestial Navigation ◽  
Wide Angle Lens ◽  
Celestial Bodies ◽  
Determination System ◽  
Fisheye Camera ◽  
Global Navigation Satellite

Celestial navigation is an important type of autonomous navigation technology which could be used as an alternative to Global Navigation Satellite Systems (GNSS) when a vessel is at sea. After several centuries of development, a variety of astronomical vessel position (AVP) determination methods have been invented, but the basic concepts of these methods are all based on angular observations with a device such as a sextant, which has disadvantages including low accuracy, manual operation, and a limited period of observation. This paper proposes a new method that utilises a fisheye camera to image the celestial bodies and horizon simultaneously. Then, we calculate the obliquity of the fisheye camera's principal optical axis according to the image coordinates of the horizon. Next, we calculate the altitude of the celestial bodies according to the image coordinates of the celestial bodies and the obliquity. Finally, the AVP is determined by the altitudes according to the robust estimation method. Experimental results indicate that this method not only could realize automation and miniaturization of the AVP determination system, but could also greatly improve the efficiency of celestial navigation.

The Research of Multipath and Linear Error for Pseudolites Applications

2011 ◽  
Vol 130-134 ◽  
pp. 2890-2893 ◽  
Author(s):  
Xiao Guang Wan ◽  
Xing Qun Zhan
Keyword(s):  
Carrier Phase ◽  
Indoor Environment ◽  
Phase Measurement ◽  
Satellite System ◽  
Independent System ◽  
Carrier Phase Measurement ◽  
Wide Range ◽  
Positioning Method ◽  
Global Navigation Satellite ◽  
Is Design

Pseudolites are ground-based transmitters that send global navigation satellite system like signals, such as GPS, GLONASS, or Galileo. As an independent system for indoor positioning, pseudolites technique can be explored for a wide range of positioning and navigation application where the signal of satellite GNSS can’t be received. However, with indoor environment, the positioning method of pseudolite navigation system is not entirely same as GNSS, and there are some challenging issues in research and system design. In this paper, a signal difference carrier phase measurement system with pseudolites is design. Furthermore, two major problems are studied that they are multipath error and linear errors.

scholarly journals Integrity Monitoring of PPP-RTK Positioning; Part I: GNSS-Based IM Procedure

2021 ◽  
Vol 14 (1) ◽  
pp. 44
Author(s):  
Kan Wang ◽  
Ahmed El-Mowafy ◽  
Weijin Qin ◽  
Xuhai Yang
Keyword(s):  
Road Transport ◽  
Satellite System ◽  
Convergence Time ◽  
Transport Systems ◽  
Navigation Satellite ◽  
Integrity Monitoring ◽  
Network Scale ◽  
Positioning Method ◽  
Multipath Environment ◽  
Global Navigation Satellite

Nowadays, integrity monitoring (IM) is required for diverse safety-related applications using intelligent transport systems (ITS). To ensure high availability for road transport users for in-lane positioning, a sub-meter horizontal protection level (HPL) is expected, which normally requires a much higher horizontal positioning precision of, e.g., a few centimeters. Precise point positioning-real-time kinematic (PPP-RTK) is a positioning method that could achieve high accuracy without long convergence time and strong dependency on nearby infrastructure. As the first part of a series of papers, this contribution proposes an IM strategy for multi-constellation PPP-RTK positioning based on global navigation satellite system (GNSS) signals. It analytically studies the form of the variance-covariance (V-C) matrix of ionosphere interpolation errors for both accuracy and integrity purposes, which considers the processing noise, the ionosphere activities and the network scale. In addition, this contribution analyzes the impacts of diverse factors on the size and convergence of the HPLs, including the user multipath environment, the ionosphere activity, the network scale and the horizontal probability of misleading information (PMI). It is found that the user multipath environment generally has the largest influence on the size of the converged HPLs, while the ionosphere interpolation and the multipath environments have joint impacts on the convergence of the HPL. Making use of 1 Hz data of Global Positioning System (GPS)/Galileo/Beidou Navigation Satellite System (BDS) signals on L1 and L5 frequencies, for small- to mid-scaled networks, under nominal multipath environments and for a horizontal PMI down to , the ambiguity-float HPLs can converge to 1.5 m within or around 50 epochs under quiet to medium ionosphere activities. Under nominal multipath conditions for small- to mid-scaled networks, with the partial ambiguity resolution enabled, the HPLs can converge to 0.3 m within 10 epochs even under active ionosphere activities.

Performance Evaluation of PPP-AR Method for Engineering Surveys with Embedded GNSS Chipset in a Smartphone

2020 ◽  
Author(s):  
Caneren Gul ◽  
Taylan Ocalan ◽  
Nursu Tunalioglu
Keyword(s):  
Satellite System ◽  
Time Interval ◽  
Dual Frequency ◽  
Economic Market ◽  
The World ◽  
Positioning Method ◽  
Gnss Receivers ◽  
Point Positioning ◽  
Global Navigation Satellite ◽  
Gnss Observations

<p>Today, traditional Precise Point Positioning (PPP) method with high-cost geodetic grade Global Navigation Satellite System (GNSS) receivers has been used commonly for surveying, navigation, geodesy, geophysics and other engineering applications where dm-cm level accuracy is required. On the other hand, while smartphones have created a growing economic market in the world, they serve positioning, navigation and timing (PNT) services in varying accuracy levels to the users besides many other facilities. One of the most significant components of the smartphones involving multi-sensors for outdoor point-positioning and navigation is the embedded GNSS chipset. Especially, the world’s first dual-frequency GNSS smartphone produced by Xiaomi in May 2018, so-called Xiaomi Mi 8, brings a new aspect to PNT applications. In this study, a smartphone with dual-frequency embedded GNSS chipset was used to analyze the performance of PPP-Ambiguity Resolution (PPP-AR) method in engineering surveys. With respect to study aim, simultaneous static GNSS observations gathered with a geodetic grade GNSS receiver and a smartphone were conducted within a test setup. The static GNSS observations were repeated for 3 days and the campaign duration was 2 hours per day at the same daily time interval. All the raw GNSS observations were converted into Receiver Independent Exchange Format (RINEX) and processed by the relative point positioning method as a reference solution initially. Later, all observations were processed by the PPP-AR method. A widely used online post-processing GNSS service, namely CSRS-PPP, which was updated in August 2018 (GPSPACE to SPARK) were employed for PPP-AR solutions. As a conclusion, we analyze the performance of the embedded dual frequency GNSS chipset and assess the feasibility of them in different engineering surveys.</p><p><strong>Keywords:</strong> Smartphone Positioning, PPP-AR, Embedded GNSS Chipset, Dual-frequency, Engineering Surveys</p>

scholarly journals An Extended Kalman Filter and Back Propagation Neural Network Algorithm Positioning Method Based on Anti-lock Brake Sensor and Global Navigation Satellite System Information

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 2753 ◽  
Author(s):  
Jie Hu ◽  
Zhongli Wu ◽  
Xiongzhen Qin ◽  
Huangzheng Geng ◽  
Zhangbin Gao
Keyword(s):  
Back Propagation ◽  
Satellite System ◽  
Back Propagation Neural Network ◽  
Low Noise ◽  
Navigation Satellite ◽  
Vehicle Speed ◽  
T Box ◽  
Positioning Method ◽  
Heading Angle ◽  
Global Navigation Satellite

Telematics box (T-Box) chip-level Global Navigation Satellite System (GNSS) receiver modules usually suffer from GNSS information failure or noise in urban environments. In order to resolve this issue, this paper presents a real-time positioning method for Extended Kalman Filter (EKF) and Back Propagation Neural Network (BPNN) algorithms based on Antilock Brake System (ABS) sensor and GNSS information. Experiments were performed using an assembly in the vehicle with a T-Box. The T-Box firstly use automotive kinematical Pre-EKF to fuse the four wheel speed, yaw rate and steering wheel angle data from the ABS sensor to obtain a more accurate vehicle speed and heading angle velocity. In order to reduce the noise of the GNSS information, After-EKF fusion vehicle speed, heading angle velocity and GNSS data were used and low-noise positioning data were obtained. The heading angle speed error is extracted as target and part of low-noise positioning data were used as input for training a BPNN model. When the positioning is invalid, the well-trained BPNN corrected heading angle velocity output and vehicle speed add the synthesized relative displacement to the previous absolute position to realize a new position. With the data of high-precision real-time kinematic differential positioning equipment as the reference, the use of the dual EKF can reduce the noise range of GNSS information and concentrate good-positioning signals of the road within 5 m (i.e. the positioning status is valid). When the GNSS information was shielded (making the positioning status invalid), and the previous data was regarded as a training sample, it is found that the vehicle achieved 15 minutes position without GNSS information on the recycling line. The results indicated this new position method can reduce the vehicle positioning noise when GNSS information is valid and determine the position during long periods of invalid GNSS information.

scholarly journals Robust Inter-Vehicle Distance Measurement Using Cooperative Vehicle Localization

Sensors ◽  
2021 ◽  
Vol 21 (6) ◽  
pp. 2048
Author(s):  
Faan Wang ◽  
Weichao Zhuang ◽  
Guodong Yin ◽  
Shuaipeng Liu ◽  
Ying Liu ◽  
...  
Keyword(s):  
Satellite System ◽  
Superior Performance ◽  
Estimation Methods ◽  
Cooperative Localization ◽  
Absolute Position ◽  
Localization Accuracy ◽  
Vehicle Localization ◽  
Communication Devices ◽  
Positioning Method ◽  
Global Navigation Satellite

Precise localization is critical to safety for connected and automated vehicles (CAV). The global navigation satellite system is the most common vehicle positioning method and has been widely studied to improve localization accuracy. In addition to single-vehicle localization, some recently developed CAV applications require accurate measurement of the inter-vehicle distance (IVD). Thus, this paper proposes a cooperative localization framework that shares the absolute position or pseudorange by using V2X communication devices to estimate the IVD. Four IVD estimation methods are presented: Absolute Position Differencing (APD), Pseudorange Differencing (PD), Single Differencing (SD) and Double Differencing (DD). Several static and dynamic experiments are conducted to evaluate and compare their measurement accuracy. The results show that the proposed methods may have different performances under different conditions. The DD shows the superior performance among the four methods if the uncorrelated errors are small or negligible (static experiment or dynamic experiment with open-sky conditions). When multi-path errors emerge due to the blocked GPS signal, the PD method using the original pseudorange is more effective because the uncorrelated errors cannot be eliminated by the differential technique.

scholarly journals Accuracy Assessment of Atlas L-band GNSS Global Correction Service and Autonomous Positioning at Perlis, Malaysia

2021 ◽  
Vol 18 (2) ◽  
pp. 57
Author(s):  
Mohd Zainee Zainal ◽  
Wan Muhammad Syafiq Wan Mohd Suhaimi ◽  
Nurul Ain Mohd Zaki ◽  
Noorzalianee Noorzalianee Ghazali ◽  
Khairulazhar Zainuddin
Keyword(s):  
Precise Point Positioning ◽  
Accuracy Assessment ◽  
Satellite System ◽  
Maritime Industry ◽  
Signal Loss ◽  
Positioning Method ◽  
L Band ◽  
Global Navigation Satellite ◽  
Classification Table ◽  
Average Position

Differential Global Navigation Satellite System (DGNSS) is the most common positioning method used for navigation in the hydrography field. During the loss of the correction signal, the differential solution becomes an autonomous solution that may affect the accuracy of the position during that time. However, the availability of the Atlas L-band global correction service that adapts the Real-Time Precise Point Positioning (RT-PPP) technique has broadened the choice of solutions that can be used for navigation in the maritime industry and may solve the problem of signal loss. This research compares the positioning between autonomous solution GNSS and Atlas L-band correction solution using the static method to assess the accuracy of positioning between both methods. Data acquisition of the autonomous positioning and Atlas L-band service was conducted by using Hemisphere receiver VS330 and antenna A43. The statistical T-test reveals that the accuracy of analysis Atlas-L band and autonomous solution GNSS using static positioning was significant, as the p < 0.05 with 95% confidence interval. Besides, the result also shows that the position given by the Atlas L-band is more accurate and precise than Autonomous Solution GNSS, with an average position of 0.479 meters and 2.281 meters, respectively. Ultimately, the continuity of positioning data given by the Atlas L-band in the northern part of Malaysia is good, and positioning using Atlas L-band can be classified as Special Order based on the classification table by the International Hydrographic Organisation (IHO). Keywords: Atlas L-Band, GNSS, RT-PPP, Autonomous Positioning

scholarly journals The Triangulation Reduction Analysis of Acute Triangle

2019 ◽  
Author(s):  
Fauzi Janu Amarrohman ◽  
L M Sabri ◽  
Moehammad Awaluddin ◽  
Bambang Darmo Yuwono
Keyword(s):  
Reference Value ◽  
Satellite System ◽  
Navigation Satellite ◽  
Total Station ◽  
The Earth ◽  
Positioning Method ◽  
Plane Projection ◽  
Acute Triangle ◽  
Global Navigation Satellite ◽  
Different Levels

Positioning on the surface of the earth using the triangulation method can be done in two ways, namely terrestrial method for example by measuring the angle and distance using the total station tool and extraterrestrial methods for example by using satellite-based positioning technology. Extraterrestrial positioning method using the global navigation satellite system combined with terrestrial methods by measuring angles and distances using the total station tool is one alternative to positioning well. In this study position determination will only be calculated using two intermediate calculation plane, on the ellipsoid projection and in the plane projection. Of course, in a process of measuring position for the same point but using different methods it will produce different levels of accuracy. From the results of the comparison in determining the definitive coordinate value generated by the count on the ellipsoid projection with the Gauss-Helmert method, the definitive value that is closer to the reference value measured by static measurements methods rather than definitive coordinates produced through calculations in the plane projection.

scholarly journals Long Baseline Tightly Coupled DGNSS Positioning with Ionosphere-Free Inter-System Bias Calibration

2020 ◽  
Vol 13 (1) ◽  
pp. 67
Author(s):  
Jianhua Cheng ◽  
Chao Jiang ◽  
Liang Li ◽  
Chun Jia ◽  
Bing Qi ◽  
...  
Keyword(s):  
Satellite System ◽  
Base Station ◽  
Coupled Method ◽  
Loosely Coupled ◽  
Long Term Stability ◽  
Long Baseline ◽  
Positioning Method ◽  
Tightly Coupled ◽  
System Bias ◽  
Global Navigation Satellite

Based on the statistical stability of the inter-system bias (ISB), we propose a tightly coupled Differential Global Navigation Satellite System (DGNSS) positioning method by using ionosphere-free combination for the long baseline applications. The proposed method is compatible with the traditional Radio Beacon (RBN) base station implementation. The tightly coupled DGNSS positioning method is utilized at the long baseline rover by eliminating the effect of ionosphere delay with ionosphere-free (IF) based differential ISB calibration. The improved positioning model strength can be obtained with the proposed method when compared with the traditional loosely coupled method, particularly under the satellite-deprived environment. GNSS datasets of different baselines were collected to test the proposed method. The results of the ISB stability show that the ISB has long-term stability and needs to be calibrated when the receiver is rebooted. The positioning results show that when compared with the IF-based loosely coupled method, the IF-based tightly coupled DGNSS method based on ISB calibration can obtain better positioning performance of accuracy and continuity within 240 km baselines.

Sign in / Sign up

Export Citation Format

Share Document