scholarly journals Testing the Functionality and Applicability of Smart Devices for a Handheld Celestial Navigation System

Naše more ◽  
2021 ◽  
Vol 68 (3) ◽  
pp. 157-166
Author(s):  
Gašper Grm ◽  
Aleksander Grm
Keyword(s):  
Celestial Body ◽  
Navigation System ◽  
Time Window ◽  
Functional System ◽  
Test System ◽  
Smart Devices ◽  
Smart Device ◽  
Navigation Systems ◽  
Celestial Navigation ◽  
Main Instrument

In this paper, the functionality and applicability of smart devices for the purpose of handheld celestial navigation systems is investigated. The main instrument used to determine observer position (altitude measurements) in celestial navigation is the sextant. The use of a sextant and almanac or computer is a classical approach to determining the observer's celestial position. This approach has two significant limitations, firstly the time window for the measurements is short, and secondly, the view of the ocean horizon must be clear. With the use of smart devices, we can overcome these two obstacles and create a so-called handheld celestial navigation system. Currently, smart devices have very accurate sensors to measure various physical quantities such as acceleration, angular velocity, orientation, etc. We are particularly interested in validating the orientation sensor for measuring the altitude and azimuth of the celestial body. The altitude of the celestial body is the primary parameter in determining the celestial position using a sextant. The idea is to replace the sextant with a smart device to measure the altitude and possibly the azimuth of the celestial body. To test this idea, two types of experiments are designed. In the first, a system on a tripod to obtain the most accurate measurements possible is set. Such tests will provide detailed information about the accuracy of the smart device's sensors and its applicability in measuring altitude and azimuth. The test system will essentially resemble a theodolite device. In the second experiment, a hands-free measurement experiment that resembles a sextant to test the idea for practical use and functionality in the process of celestial positioning is set. The observed data show that the results of the measurements under controlled conditions are promising and within reasonable bounds for the accuracy of celestial positioning. Estimates of the position error by the graphical method are in the range of 10 Nm to 30 Nm. In order to obtain a fully functional stand-alone celestial positioning system, the proposed assembly needs to be improved through several unchallenging upgrades. A fully functional system can be considered as a cheap off-the-shelf handheld Celestial Navigational System (CNS).

Solar TDOA measurement and integrated navigation for formation flying

2019 ◽  
Vol 233 (12) ◽  
pp. 4635-4645
Author(s):  
Ziyuan Yu ◽  
Jin Liu ◽  
Chao Pan ◽  
Lvqian Guo ◽  
Zhiwei Kang ◽  
...  
Keyword(s):  
Navigation System ◽  
Formation Flying ◽  
Time Of Arrival ◽  
Navigation Systems ◽  
Integrated Navigation ◽  
Free Standing ◽  
Solar Time ◽  
Satellite Link ◽  
Celestial Navigation ◽  
The Difference

To improve the positioning accuracy of autonomous celestial navigation systems when flying in formation, we exploit the fact that the sole light source in the solar system is the Sun to directly provide positioning information for relative navigation. We term this solar Time Difference of Arrival (TDOA) navigation for formation flying. Solar light has the potential to provide a solar Time of Arrival (TOA) because of its unstable intensity. However, the solar TOA cannot be used for navigation because it has no baseline. To solve this problem, we took the difference between the solar TOAs of two spacecraft (the solar TDOA) as the basis for navigational measurement. The solar TDOA represents the relative distance between two spacecraft in a radial direction. However, whilst the solar TDOA is insensitive to solar direction errors, a free-standing solar TDOA navigation system is not observable. We therefore combined the solar TDOA with the Mars direction and inter-satellite link navigation system, to form an integrated solar TDOA/Mars direction/inter-satellite link navigation method for formation flying. Simulation results indicate that solar TDOA-based integrated navigation for formation flying can provide highly accurate navigation information, especially under relative conditions.

Automatic Radio-celestial Navigation

1959 ◽  
Vol 12 (3-4) ◽  
pp. 249-259 ◽  
Author(s):  
Gene R. Marner
Keyword(s):  
High Altitude ◽  
Navigation System ◽  
Navigation Systems ◽  
Operational Conditions ◽  
Celestial Navigation ◽  
Long Duration ◽  
Celestial Bodies ◽  
The Many ◽  
Continuous Determination

The accurate, continuous determination of position, heading and course at all times, under all normal operational conditions, would be very desirable. This ideal has not been achieved for flights or voyages of long duration, but the many developments of recent years begin to give some promise that it may be possible. For high altitude aircraft the continuous optical observation of celestial bodies offers an evident solution, and doppler systems can give continuous speed over ground. For ships, however, the attainment of such an ideal navigation system is difficult. The various shore-based radio navigation systems have made important contributions, as have the development of inertial techniques. In addition, automatic optical sextants have been developed which can be used in clear weather.

Utilisation of Robotic Navigation Systems in the Treatment of Atrial Fibrillation

2010 ◽  
Vol 6 (3) ◽  
pp. 60
Author(s):  
Richard Schilling ◽  
Keyword(s):  
Atrial Fibrillation ◽  
Catheter Ablation ◽  
Navigation System ◽  
Antiarrhythmic Drugs ◽  
Rhythm Control ◽  
Navigation Systems ◽  
Robotic Navigation ◽  
Increased Risk ◽  
Common Strategy ◽  
Catheter Navigation

Atrial fibrillation (AF) is linked to an increased risk of adverse cardiovascular events. While rhythm control with antiarrhythmic drugs (AADs) is a common strategy for managing patients with AF, catheter ablation may be a more efficacious and safer alternative to AADs for sinus rhythm control. Conventional catheter ablation has been associated with challenges during the arrhythmia mapping and ablation stages; however, the introduction of two remote catheter navigation systems (a robotic and a magnetic navigation system) may potentially overcome these challenges. Initial clinical experience with the robotic navigation system suggests that it offers similar procedural times, efficacy and safety to conventional manual ablation. Furthermore, it has been associated with reduced fluoroscopy exposure to the patient and the operator as well as a shorter fluoroscopy time compared with conventional catheter ablation. In the future, the remote navigation systems may become routinely used for complex catheter ablation procedures.

scholarly journals MS-2 Minimally invasive glioma surgery with navigation system and tubular retractor

2020 ◽  
Vol 2 (Supplement_3) ◽  
pp. ii2-ii3
Author(s):  
Kazuhiko Kurozumi
Keyword(s):  
Navigation System ◽  
Diffusion Tensor ◽  
Therapeutic Option ◽  
Normal Brain ◽  
Navigation Systems ◽  
Glioma Surgery ◽  
Tubular Retractor ◽  
Neuronavigation System ◽  
Magnetic Resonance Imaging Mri ◽  
Neurological Surgery

Abstract Navigation systems are reliable and safe for neurological surgery. Navigation is an attractive and innovative therapeutic option. Recently, endo and exoscopic surgeries have been gradually increasing in neurosurgery. We are currently trialing to use 4K and 8K systems to improve the accuracy and safety of our surgical procedures. Surgeries for deep-seated tumors are challenging because of the difficulty in creating a corridor and observing the interface between lesions and the normal area. In total, 315 patients underwent surgery at Okayama University between 2017 and 2019. Among them, we experienced 92 glioma surgeries using navigation systems. Preoperatively, we performed computed tomography imaging and contrast-enhanced magnetic resonance imaging (MRI) for the neuronavigation system. We experienced Curve(TM) Image Guided Surgery (BrainLab, Munich, Germany). The surgical trajectory was planned with functional MRI and diffusion tensor imaging to protect the eloquent area and critical vasculature of the brain. We used a clear plastic tubular retractor system, the ViewSite Brain Access System, for surgery of deep seated gliomas. We gently inserted and placed the ViewSite using the neuronavigation. The tumor was observed and resected through the ViewSite tubular retractor under a microscope and endoscope. If the tumor was large, we switched the ViewSite tubular retractor to brain spatulas to identify the boundary between the normal brain and lesion. We are currently using the combination of the tubular retractor and brain spatulas using navigation system. Here, we present and analyze our preoperative simulation, surgical procedure, and outcomes.

scholarly journals Latency-Optimal Computational Offloading Strategy for Sensitive Tasks in Smart Homes

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2347
Author(s):  
Yanyan Wang ◽  
Lin Wang ◽  
Ruijuan Zheng ◽  
Xuhui Zhao ◽  
Muhua Liu
Keyword(s):  
Queue Length ◽  
Optimization Problem ◽  
Time Slot ◽  
Smart Homes ◽  
Back Pressure ◽  
Smart Devices ◽  
Smart Device ◽  
Simulation Results ◽  
Computational Offloading ◽  
The Stability

In smart homes, the computational offloading technology of edge cloud computing (ECC) can effectively deal with the large amount of computation generated by smart devices. In this paper, we propose a computational offloading strategy for minimizing delay based on the back-pressure algorithm (BMDCO) to get the offloading decision and the number of tasks that can be offloaded. Specifically, we first construct a system with multiple local smart device task queues and multiple edge processor task queues. Then, we formulate an offloading strategy to minimize the queue length of tasks in each time slot by minimizing the Lyapunov drift optimization problem, so as to realize the stability of queues and improve the offloading performance. In addition, we give a theoretical analysis on the stability of the BMDCO algorithm by deducing the upper bound of all queues in this system. The simulation results show the stability of the proposed algorithm, and demonstrate that the BMDCO algorithm is superior to other alternatives. Compared with other algorithms, this algorithm can effectively reduce the computation delay.

An Improved and Efficient Algorithm for SINS/GPS/Doppler Integrated Navigation Systems

2012 ◽  
Vol 245 ◽  
pp. 323-329 ◽  
Author(s):  
Muhammad Ushaq ◽  
Jian Cheng Fang
Keyword(s):  
Kalman Filter ◽  
Navigation System ◽  
Inertial Navigation System ◽  
Inertial Sensor ◽  
Inertial Navigation ◽  
Measurement Unit ◽  
Navigation Systems ◽  
Integrated Navigation ◽  
Efficient Manner ◽  
Position Errors

Inertial navigation systems exhibit position errors that tend to grow with time in an unbounded mode. This degradation is due, in part, to errors in the initialization of the inertial measurement unit and inertial sensor imperfections such as accelerometer biases and gyroscope drifts. Mitigation to this growth and bounding the errors is to update the inertial navigation system periodically with external position (and/or velocity, attitude) fixes. The synergistic effect is obtained through external measurements updating the inertial navigation system using Kalman filter algorithm. It is a natural requirement that the inertial data and data from the external aids be combined in an optimal and efficient manner. In this paper an efficient method for integration of Strapdown Inertia Navigation System (SINS), Global Positioning System (GPS) and Doppler radar is presented using a centralized linear Kalman filter by treating vector measurements with uncorrelated errors as scalars. Two main advantages have been obtained with this improved scheme. First is the reduced computation time as the number of arithmetic computation required for processing a vector as successive scalar measurements is significantly less than the corresponding number of operations for vector measurement processing. Second advantage is the improved numerical accuracy as avoiding matrix inversion in the implementation of covariance equations improves the robustness of the covariance computations against round off errors.

Ephemeris Error Correction in Celestial Navigation System Considering Earth’s Precession-Nutation

Optik ◽  
2020 ◽  
pp. 166152
Author(s):  
Bin Gou ◽  
Ke-yu Qi ◽  
Yong-mei Cheng ◽  
Yuan-yuan Xu ◽  
Zhen Sun
Keyword(s):  
Error Correction ◽  
Navigation System ◽  
Celestial Navigation

Initial Alignment of a Moving Inertial Navigation System

1960 ◽  
Vol 13 (3) ◽  
pp. 301-315
Author(s):  
Richard B. Seeley ◽  
Roy Dale Cole
Keyword(s):  
Navigation System ◽  
Inertial Navigation System ◽  
Local Level ◽  
Inertial Navigation ◽  
Navigation Systems ◽  
Velocity Measurements ◽  
Initial Alignment ◽  
Inertial Navigation Systems ◽  
Error Sources ◽  
China Lake

This paper describes and discusses some of the techniques by which a moving inertial platform may be aligned by using external velocity measurements and also presents some of the major problems and error sources affecting such alignment. It is based upon the results of a 3-year study, of inertial and doppler-inertial navigation at the Naval Ordnance Test Station, China Lake, California, and, in general, applies to inertial navigation systems which erect to either the local level or the mass-attraction vertical. Although rudimentary derivations are made of the alignment techniques, the paper is largely nonmathematical for ease of reading. Emphasis is placed upon the major errors affecting the alignment. This paper describes and discusses some of the techniques by which a moving inertial platform may be aligned by using external velocity measurements and also presents some of the major problems and error sources affecting such alignment. It is based upon the results of a 3-year study, of inertial and doppler-inertial navigation at the Naval Ordnance Test Station, China Lake, California, and, in general, applies to inertial navigation systems which erect to either the local level or the mass-attraction vertical. Although rudimentary derivations are made of the alignment techniques, the paper is largely nonmathematical for ease of reading. Emphasis is placed upon the major errors affecting the alignment.

scholarly journals Design of Accurate Navigation System by Integrating INS and GPS modules

2019 ◽  
Vol 11 (4) ◽  
pp. 139-154
Author(s):  
M. RAJA ◽  
Gaurav ASTHANA ◽  
Ajay SINGH ◽  
Ashna SINGHAL ◽  
Pallavi LAKRA
Keyword(s):  
Navigation System ◽  
Inertial Navigation System ◽  
External Information ◽  
Navigation Systems ◽  
Final Solution ◽  
Long Term Stability ◽  
Noise Characteristics ◽  
Aircraft Navigation ◽  
Satellite Signal

Navigation has a huge application in aviation and aircraft automatic approach. Two widely used navigation systems are Global position System (GPS) and Inertial Navigation System (INS). Triangulation method used to determine the aircrafts location by GPS, speed whereas an INS, with the aid of gyroscope and accelerometer, estimates the location, velocity and alignment of an aircraft. Aircraft navigation is a complex task and using only one of the above navigation systems results in inaccurate and insufficient data. GPS stops working when satellite signal is not received, susceptible to interfere occasionally has high noise content, and has a low bandwidth, INS system requires external information for initialization has long-term drift errors. Certain errors like ionosphere interference, clock error, orbital error, position error, etc. might arise and disrupt the navigation process. In order to outrun the limitations of the above two systems and counter the errors, both INS and GPS can be integrated and used to attain more smooth, accurate and faster aircraft attitude estimates, as they have complementary strengths and limitations. GPS is stable for a long period and can act as an independent navigation system whereas INS is not susceptible to interference and signal losses has high radio bandwidth and works well for short intervals of time. In order to get accurate and precise attitude estimation, calculation of the parameters at different altitude using both systems is done; furthermore the comparison and contrast between the results is performed, measured quantities are transformed between various frames like longitudinal to rolling, calculation and elimination of errors is done producing the final solution. Because of integrated GPS and INS, the navigation system exhibits robustness, higher bandwidth, better noise characteristics, and long-term stability.

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