Geomagnetic Navigation Research Articles

Bio-inspired geomagnetic navigation method for autonomous underwater vehicle

Bio-inspired geomagnetic navigation method for autonomous underwater vehicle

Progress, Contribution and Challenges of Earth-Magnetism Navigation

Navigation and positioning technology has stepped into the era of all schools of thoughts contend for attention. The progress, application, contribution and challenges of geomagnetic navigation technology are reviewed and analyzed. This paper introduces the principle and steps of geomagnetic navigation system, then compared with a variety of navigation technology to get the advantages and disadvantages of geomagnetic navigation; Summary of major contribution of geomagnetic navigation technology in the field of navigation and positioning; Finally briefly examine the important applications and the major challenges of geomagnetic navigation technology.

Compensation of Geomagnetic Vector Measurement System With Differential Magnetic Field Method

The accurate measurement of a geomagnetic field is a key technology in many applications, such as magnetic anomaly detection, underwater geomagnetic navigation, and motion tracking. However, the magnetic interference fields, such as ferromagnetic parts and other electric equipments, will seriously influence the measurement accuracy of geomagnetic vector measurement system, and thus should be compensated. In this paper, a new compensation method using differential magnetic field is proposed. As a first step, a permanent magnet with different relative positions is used to change the ambient magnetic field to construct the error model equations about unknown quantities, and the soft-iron error parameters can be estimated by solving equations with nonlinear least square method. Then, the hard-iron error parameters can be estimated by changing the fixation direction of the three-axis magnetometer. Finally, the estimated error parameters are used for compensating the magnetic interference field. In order to verify effectiveness of the proposed method, simulation and experiment are performed, and the results demonstrate that the proposed method estimates error parameters accurately and improves the measurement accuracy of geomagnetic vector measurement system greatly.

A Missile-Borne Angular Velocity Sensor Based on Triaxial Electromagnetic Induction Coils.

Aiming to solve the problem of the limited measuring range for angular motion parameters of high-speed rotating projectiles in the field of guidance and control, a self-adaptive measurement method for angular motion parameters based on the electromagnetic induction principle is proposed. First, a framework with type bent “I-shape” is used to design triaxial coils in a mutually orthogonal way. Under the condition of high rotational speed of a projectile, the induction signal of the projectile moving across a geomagnetic field is acquired by using coils. Second, the frequency of the pulse signal is adjusted self-adaptively. Angular velocity and angular displacement are calculated in the form of periodic pulse counting and pulse accumulation, respectively. Finally, on the basis of that principle prototype of the sensor is researched and developed, performance of measuring angular motion parameters are tested on the sensor by semi-physical and physical simulation experiments, respectively. Experimental results demonstrate that the sensor has a wide measuring range of angular velocity from 1 rps to 100 rps with a measurement error of less than 0.3%, and the angular displacement measurement error is lower than 0.2°. The proposed method satisfies measurement requirements for high-speed rotating projectiles with an extremely high dynamic range of rotational speed and high precision, and has definite value to engineering applications in the fields of attitude determination and geomagnetic navigation.

The Vector Matching Method in Geomagnetic Aiding Navigation.

In this paper, a geomagnetic matching navigation method that utilizes the geomagnetic vector is developed, which can greatly improve the matching probability and positioning precision, even when the geomagnetic entropy information in the matching region is small or the geomagnetic contour line’s variety is obscure. The vector iterative closest contour point (VICCP) algorithm that is proposed here has better adaptability with the positioning error characteristics of the inertial navigation system (INS), where the rigid transformation in ordinary ICCP is replaced with affine transformation. In a subsequent step, a geomagnetic vector information fusion algorithm based on Bayesian statistical analysis is introduced into VICCP to improve matching performance further. Simulations based on the actual geomagnetic reference map have been performed for the validation of the proposed algorithm.

Evaluation of ICCP algorithm for geomagnetic navigation based on hardware-in-the-loop simulation

Evaluation of ICCP algorithm for geomagnetic navigation based on hardware-in-the-loop simulation

Geomagnetic imprinting predicts spatio-temporal variation in homing migration of pink and sockeye salmon.

Animals navigate using a variety of sensory cues, but how each is weighted during different phases of movement (e.g. dispersal, foraging, homing) is controversial. Here, we examine the geomagnetic and olfactory imprinting hypotheses of natal homing with datasets that recorded variation in the migratory routes of sockeye (Oncorhynchus nerka) and pink (Oncorhynchus gorbuscha) salmon returning from the Pacific Ocean to the Fraser River, British Columbia. Drift of the magnetic field (i.e. geomagnetic imprinting) uniquely accounted for 23.2% and 44.0% of the variation in migration routes for sockeye and pink salmon, respectively. Ocean circulation (i.e. olfactory imprinting) predicted 6.1% and 0.1% of the variation in sockeye and pink migration routes, respectively. Sea surface temperature (a variable influencing salmon distribution but not navigation, directly) accounted for 13.0% of the variation in sockeye migration but was unrelated to pink migration. These findings suggest that geomagnetic navigation plays an important role in long-distance homing in salmon and that consideration of navigation mechanisms can aid in the management of migratory fishes by better predicting movement patterns. Finally, given the diversity of animals that use the Earth's magnetic field for navigation, geomagnetic drift may provide a unifying explanation for spatio-temporal variation in the movement patterns of many species.

Long-Distance Geomagnetic Navigation: Imitations of Animal Migration Based on a New Assumption

Plenty of evidence has implied that animals like pigeons and sea turtles utilize geomagnetic information for long-distance migration and homing. In this paper, we conduct an ab initio investigation to imitate a migratory animal's geomagnetic homing across a long distance over the surface of the Earth. Based on a simple assumption that such animals have a natural ability to sense and compare the included angle between the vector geomagnetic field (GF) and a specific geographic direction such as the due north, we show that a long-distance geomagnetic navigation (GN) can be accomplished without any assistance of prestored geomagnetic and geographic information, as long as the navigation is inside a vast area where such a spatial angle can uniquely determine a geographic location. Without any requirement of measuring the strength of the GF, this GN will not be visibly affected by the recurrent fluctuation of the GF that severely hampers traditional GN. By introducing the extended-Kalman-filter algorithm, it is able to find a shortcut in the geomagnetic space, overcoming interferences of strong Gaussian and local-area geomagnetic anomaly. We believe that the proposed approach will find a wide range of potential applications in global, local, and indoor navigations based on magnetic field in the future.

Research of Interference Field Measurement and Error Compensation for Geomagnetic Navigation

Aiming at removing interference field in the geomagnetic navigation, the technology of interference magnetic field measurement and error compensation are studied. The scheme of error measuring and compensating are designed, the compensation model is established based on the magnetic dipole theory, its calculation method is designed, experiments prove that this technology is of high accuracy and its process is simpler, it provides a new way for eliminating interference in the aeromagnetic survey.

An Aeromagnetic Compensation Algorithm for Aircraft Based on Fuzzy Adaptive Kalman Filter

In order to ensure the effectiveness of geomagnetic navigation, as the foundation, the precise measurement of geomagnetic field must be guaranteed; namely, aircraft aeromagnetic compensation is worthy of being further studied. In this paper, the classical aircraft aeromagnetic compensation algorithm based on Leliak Model is analyzed and an aircraft aeromagnetic compensation algorithm based on fuzzy adaptive Kalman filter is proposed, which is a new approach for aircraft to achieve aeromagnetic compensation. Simulation results show that it has better compensation performance without relying on the aircraft attitude.

Method and experiment for compensating the interferential magnetic field in underwater vehicle

It is the key technique for underwater geomagnetic navigation to compensate vehicle interferential magnetic field. The essential of interferential field compensation is to estimate model parameters of interferential fields and use the parameters to compute geomagnetic field. The rank-deficient problem will appear with least square method because the distribution of measurement data in gesture space is insufficient. In this paper, the vehicle voyage track is optimized to improve the completeness of measurement data and differential evolution (DE) algorithm is adopted to estimate model parameters of interferential magnetic field. Underwater experiments are carried out to validate the compensation effect. After compensation, the measurement error of geomagnetic field has decreased from more than ten thousands nT to tens of nT. Compared with least-square algorithm, the DE algorithm has better performance in accuracy. The results demonstrate that the proposed method can effectively compensate vehicle interferential field effectively and thus improve measurement accuracy of geomagnetic field for underwater vehicle.

Study on the Influence of Downward Continuation on Matching Suitability in Underwater Geomagnetic Navigation

Geomagnetic matching is to utilize the geomagnetic field for positioning, and the matching suitability of candidate matching areas (CMAs) is a key factor of affecting matching precision. In underwater geomagnetic navigation, the underwater geomagnetic map is usually obtained by downward continuation, and therefore the influence of downward continuation on matching suitability is studied in this article. Firstly, the downward continuation algorithm is briefly introduced. Then the comparison analysis of matching suitability before and after downward continuation is made from an experimental point of view. Results show that the CMAs that own excellent matching suitability can still keep the well matching suitability, and moreover, for the CMAs whose matching suitability is normal or bad, the matching suitability may be improved after downward continuation. The conclusions of this article may provide helpful lessons for matching suitability analysis in underwater geomagnetic navigation.

The Study of Degaussing Technology for Underwater Vehicle

The underwater vehicle is mainly made of ferromagnetic material, the sensor measured except magnetic field, besides magnetic field that the vehicle of the inherent hard magnetic and soft magnetic materials produce and vehicle magnetic fields produced in mechanical and electrical equipment. At the same time, the precision of the geomagnetic measurements will be affected by sensor manufacturing error and installation error factors. Therefore, how to extract the magnetic field from complex environment is a real time measurement of a difficult problem. In this paper, it is based on soft compensation. The magnetic survey experiment that underwater carrier rotates 360 degrees underwater has been done on this basis, and the effect of underwater carrier on cesium magnetometer in different heading is analyzed. The degaussing algorithm for own magnetic field of carrier is obtained and the real value of underwater magnetic field can be restored. It is the solid foundation of high precision underwater geomagnetic navigation and establishing the underwater geomagnetic map.

Magnetic interferential field compensation in geomagnetic measurement

The accurate measurement of a geomagnetic field is a key technology in geomagnetic navigation. Many magnetic interferential fields on navigation vehicles, such as ferromagnetic parts and electric equipments, will seriously disturb the magnetometer, and thus should be compensated. This paper develops a new magnetic interferential field compensation method using three-axial magnetometer measurements. The method relies on a formulation derived from the difference of the measured geomagnetic magnitude and its true value. The goal is to evaluate the magnetic interferential field parameters first and then compensate the measurements with them. The trust-region method is adopted to evaluate the parameters in the formulation. A simulation is conducted to test the validity of the method. An experiment is designed and implemented on an underwater vehicle. Both simulation and experimental results indicate that vehicle magnetic interferential field can be well compensated with this method.

A New Compensation Method for the Magnetic Interference of Vehicle

It is unavoidable that the geomagnetic field measurement is interfered by the vehicle magnetic field in geomagnetic navigation. In order to improve the measurement accuracy, the magnetic interference of vehicle must be correctly compensated. Based on the ellipse fitting compensation method, a new 3D magnetic interference compensation method is proposed. The proposed method improves the vehicle magnetic interference compensation method from 2D ellipse fitting to 3D ellipsoid fitting by the least square algorithm of ellipsoid restriction, which relaxes the restriction on 2D motion of vehicles. And a computing method of the compensation parameters is proposed to decrease the load of calculation. Finally, the experiment shows that the compensation method can compensate the vehicle 3D magnetic interference efficiently.

Magnetic enhancement of Baltic Sea sapropels by greigite magnetofossils

Magnetotactic bacteria (MTB) are known to biosynthesise single-domain magnetite (Fe3O4) for geomagnetic navigation and their relict magnetosomes (called magnetofossils) can control the magnetic properties of lake and marine sediments. Magnetotactic bacteria also produce greigite (Fe3S4) magnetosomes but, compared to those made of magnetite, relatively little is known about the sedimentary environments where they are produced and the magnetic properties of the preserved particles. We studied the magnetic properties of sediment cores from two basins (the North Central Baltic Proper and eastern Gotland Basin) that currently experience hypoxia and we discovered the magnetic enhancement of older laminated sapropels, which are a signal of past occurrences of anoxia and hypoxia in the Baltic Sea. Magnetic concentrates extracted from the laminated sapropels were characterised by transmission electron microscopy and energy dispersive X-ray spectrometry and we identified only single-domain greigite (Fe3S4) particles with a mean size of 55×75nm, which we interpret as magnetofossils due to diagnostic chains of individual particles separated by an intact dividing membrane. The degree of magnetic enhancement in the laminated sapropels has a positive relationship with loss-on-ignition data, which indicates a link between the production of greigite magnetosomes, organic matter supply and preservation and redox conditions. The coercive force of collections of non-interacting greigite magnetofossils is ∼13mT, which is considerably lower than the magnetite counterparts (∼30mT) and strictly non-bacterial and larger greigite single-domain grains (∼60mT). The values of the interparametric ratios of SIRM/χ, χARM/SIRM and χARM/χ that we obtain for our greigite magnetofossils overlap with those previously considered to be diagnostic of magnetosomal magnetite. The presence of bacterial greigite, which is easily detected by magnetic measurements, forms a proxy for hypoxia and anoxia, thus aiding the palaeoenvironmental interpretation of how oxygen conditions in the Baltic Sea have changed over time.

Nonlinear filtering techniques for geomagnetic navigation

This article focuses on the application of different nonlinear filtering techniques for geomagnetic navigation, including extended Kalman filter, unscented Kalman filter, particle filter and extended Kalman particle filter. The research evaluates the four methods for navigation of missile during its cruise phase. The measurement equations are obtained by using a surface spline method with the real regional geomagnetic data. Simulation results show all the filters have good performance in areas with abundant geomagnetic information. Among the four filters, unscented Kalman filter tops in the convergence rate and precision with a fairly low tuning sensitivity to the flight path. As the performance of unscented Kalman filter effect is influenced by unscented conversion parameters, a method of parameters optimization using genetic algorithm is presented. The method’s feasibility is further demonstrated by robustness analysis of optimal parameters.

An autonomous navigation scheme based on geomagnetic and starlight for small satellites

According to the characteristics of celestial navigation system (CNS) and geomagnetic navigation system (GNS), a fully autonomous geomagnetic/celestial integrated navigation scheme (GNS/CNS) is proposed for small satellites. By using a large-view-field star sensor to obtain the starlight vectors of multi-stars, CNS can make up the shortcoming of navigation accuracy of GNS. The system model of GNS/CNS is deduced and established in detail, and UKF (unscented Kalman filter) algorithm is used to estimate and obtain high precision navigation parameters. Simulation results show that superior position, velocity and attitude accuracy of small satellites can be obtained by GNS/CNS, and the filter has stronger filtering adaptability and stability, which demonstrate the feasibility and effectiveness of this scheme.

Where on earth can animals use a geomagnetic bi‐coordinate map for navigation?

Many animal taxa have been shown to possess the ability of true navigation. In this study we investigated the possibilities for geomagnetic bi‐coordinate map navigation in different regions of the earth by analysing angular differences between isolines of geomagnetic total intensity and inclination. In ‘no‐grid’ zones where isolines were running almost parallel, efficient geomagnetic bi‐coordinate navigation would probably not be feasible. These zones formed four distinct areas with a north‐south extension in the northern hemisphere, whereas the pattern in the southern hemisphere was more diffuse. On each side of these zones there was often a mirror effect where identical combinations of the geomagnetic parameters appeared. This may potentially cause problems for species migrating long distances east‐west across longitudes, since they may pass areas with identical geomagnetic coordinates. Migration routes assumed for four populations of migratory passerine birds were used to illustrate the possibilities of geomagnetic bi‐coordinate map navigation along different routes. We conclude that it is unlikely that animal navigation is universally based on a geomagnetic bi‐coordinate map mechanism only, and we predict that the relative importance of geomagnetic coordinate information differs between animals, areas and routes, depending on the different conditions for bi‐coordinate geomagnetic navigation in different regions of the earth.

A real-time intelligent route planning method in geomagnetic navigation

A real-time intelligent route planning method is proposed in this paper for the geomagnetic navigation. Borrow ideas from classical particle swarm optimisation (PSO) algorithm, a two-subpopulation particle swarm optimisation (TSPSO) algorithm is given, which can track the changeable environment factor quickly and accurately. Based on TSPSO algorithm, a real-time route planning algorithm is researched including its two key points: route node extension and fitness function calculation. Simulation experiment results indicate that the real-time route planning method designed in this paper can track the changeable environment factor intelligently and replan a new route in time.