Combined Use of Space Borne Optical and SAR Data to Improve Knowledge about Sea Ice for Shipping

As a first step towards a new combined product for sea ice classification based on optical/thermal data collected by Sentinel-3 satellites and SAR data from Sentinel-1 satellites, which can be used as an appropriate support for navigation in Arctic and sub-Arctic waters, two existing classification algorithms are adapted to these data. The classification based on optical data has improved, so it is expected that the results will be ideally suited to be processed together with SAR data into significantly improved sea ice information products to support marine navigation. The usefulness of the combined processing is demonstrated by means of two simple algorithms and a more sophisticated approach is outlined, which will be realized in the future in order to form the basis for an integration into an operational service with the involvement of further partners and users.

Distribution of Tide Type in Indonesian Waters Based on 7 Days Data Measurement of Ipasoet-BIG Station

Tidal data is needed in the field of energy, marine navigation, coastal construction and other activities related to the oceans. Tidal phenomena occur due to the interaction of the earth with space objects. The sea level rise in coastal waters can be modeled by a harmonic function containing tidal constant numbers. From the constants formed can be calculated a Formzahl number that shows the type of tides that occur at the observation station. This paper tries to describe the distribution pattern of tidal types that exist in Indonesian waters based on data observation collected at station belong to the Geospatial Information Agency. The result is that there are 4 types of tides in Indonesian waters, with the most dominant distribution are mixed tide, prevailing semi diurnal typel.

Precision Temperature Control for the Laser Gyro Inertial Navigation System in Long-Endurance Marine Navigation

In the Ring Laser Gyro Inertial Navigation System (RLG INS), the temperature characteristics of the accelerometer can directly influence the measurement results. In order to improve navigation accuracy in long-endurance marine navigation, the operating temperature of the accelerometer should be precisely controlled. Based on thermal studies on the accelerometer, temperature control precision should be better than 0.01 °C to achieve 1 × 10−5 m/s2 output accuracy of the accelerometer. However, this conclusion is obtained by approximate calculations and cannot be directly applied to different inertial navigation systems. In order to verify this thermal conclusion and broaden its application, the Back Propagation Neural Network (BP-NN) algorithm is adopted to validate the feasibility of temperature control in this paper. In addition, a multi-level temperature control system is also set up and carefully designed to support the validation and experiments under different conditions. Test results of the temperature control system prove that operating temperature variation can be reduced to 0.01 °C. Meanwhile, the standard deviation per hundred seconds of the accelerometer outputs, after temperature control, reaches 1 × 10−5 m/s2. Static altitude and navigation results were improved by 41.97% and 62.91%, respectively, with the precision temperature control system, which meets the long-endurance marine navigation requirements.

Radio navigation systems: definitions and classifications

Radio navigation systems (RNSs) are commonly applied in air, land and marine navigation. They are most often used for position determination. However, when comparing the definitions of this concept provided by global organisations, such as the International Association of Marine Aids to Navigation and Lighthouse Authorities (IALA), International Civil Aviation Organization (ICAO), International Maritime Organization (IMO) or International Telecommunication Union (ITU), it should be noted that the definitions presented differ significantly. Due to the ambiguity and numerous contradictions, the RNS classification varies depending on the definition of the term ‘radio navigation’ adopted, which poses serious interpretation problems. This article analyses the concept of radio navigation based on the most important global documents and legal acts on this issue. It points to fundamental differences in the understanding of the term and proposes the adoption of a new, uniform definition for air, land and marine navigation. Based on this definition, the current paper proposes a uniform RNS classification. The proposed definition of the concept of radio navigation and the resulting RNS classification are essential for the understanding of this term to achieve global uniformity and fundamental to the harmonious development of the scientific discipline of navigation. The current proposal should initiate a discussion on the meaning of the concept of radio navigation and the RNS classification.

Performance Evaluation of IMU and DVL Integration in Marine Navigation

Global navigation satellite system (GNSS) spoofing poses a significant threat to maritime logistics. Many maritime electronic devices rely on GNSS time, positioning, and speed for safe vessel operation. In this study, inertial measurement unit (IMU) and Doppler velocity log (DVL) devices, which are important in the event of GNSS spoofing or outage, are considered in conventional navigation. A velocity integration method using IMU and DVL in terms of dead-reckoning is investigated in this study. GNSS has been widely used for ship navigation, but IMU, DVL, or combined IMU and DVL navigation have received little attention. Military-grade sensors are very expensive and generally cannot be utilized in smaller vessels. Therefore, this study focuses on the use of consumer-grade sensors. First, the performance of a micro electromechanical system (MEMS)-based yaw rate angle with DVL was evaluated using 60 min of raw data for a 50 m-long ship located in Tokyo Bay. Second, the performance of an IMU-MEMS using three gyroscopes and three accelerometers with DVL was evaluated using the same dataset. A gyrocompass, which is equipped on the ship, is used as a heading reference. The results proved that both methods could achieve less than 1 km horizontal error in 60 min.

e-Navigating in highly-constrained waters: a case study of the Vistula Lagoon

In recent years the transition of marine navigation to the digital era has been gaining momentum. Implementation of e-Navigation solutions varies from country to country in terms of their priorities, goals, levels and effects. Maritime authorities in Poland have been setting the pace in this transition process, not only in Poland but also in general as a global solution. The most recent example is the planned deployment of a variety of e-Navigation tools in the Vistula Lagoon: from GNSS-RTK Ground-Based Augmentation System, to virtual and synthetic aids to navigation, high-resolution bathymetry and advanced navigational software for piloting. The major objectives of this paper are, first, to summarise recent dynamics in the e-Navigation field, and second, to present a practical implementation of the e-Navigation concept in the Vistula Lagoon area.