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3 TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

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A PPP baseline approach for bridge passing

Lass C.

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

2023

Vol. 17 No. 1

33--40

Global Navigation Satellite Systems (GNSS) are increasingly used as the main source of Positioning, Navigation and Timing (PNT) information for inland water navigation. In order to enable automated driving and facilitate driver assistant functions, it becomes of crucial importance to ensure high reliability and accuracy of the GNSS-based navigation solution, especially in challenging environments. One challenging phase of inland waterway navigation is bridge passing which leads to non-line-of-sight (NLOS) effects such as multipath and loss of tracking. This work presents a Precise Point Positioning (PPP) based algorithm in a two-antenna system where one antenna is at the bow and the other is at the stern. Additionally, gyroscope data from an IMU is used. In contrast to a separated position calculation of the two antennas, only one antenna position is estimated and the other is derived from the baseline between the antennas. This allows for accurate positioning even if one antenna does not receive any GNSS measurements. The presented scheme is evaluated using real measurement data from an inland water scenario with multiple bridges. In comparison with a standard PPP scheme as well as an RTK algorithm, the presented approach shows clear advantages in challenging scenarios.

Evolution of SBAS/EGNOS enabled devices in maritime

López M., Antón V.

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

2021

Vol. 15 No. 3

543--549

The maritime sector was one of the first communities that recognized and exploited the opportunities and advantages provided by Global Navigation Satellite Systems (GNSS). In fact, GNSS have become the primary means of obtaining Position, Navigation and Timing (PNT) information at sea. Most of the ships in the world are equipped with GNSS receivers. GPS provides the fastest and most accurate method for mariners to navigate, measure speed, and determine location. However, its performance can be enhanced by taking advantage of augmentation systems such as differential GNSS or Satellite-Based Augmentation Systems (SBAS/EGNOS), especially in terms of accuracy. Direct access to EGNOS in vessels can be achieved through EGNOS-enabled navigation receivers and EGNOS-enabled AIS transponders. This paper provides an analysis of the number of onboard devices, mainly devoted to navigation purposes, and AIS transponders which are SBAS compatible. In addition, other equipment using GNSS positioning in the maritime and inland waterways domains are also considered for the analysis of SBAS compatibility, including inland AIS, Portable Pilot Units (PPUs) and Dynamic Positioning (DP) equipment. A first survey was done in 2017 to have an overview of the percentage of SBAS enabled devices available in the maritime market [8]. Since then, the analysis has been yearly updated to understand the market evolution in terms of SBAS compatibility and its main results are summarised in this paper.

Development of precise point positioning algorithm to support advanced driver assistant functions for inland vessel navigation

Lass C., Ziebold R.

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

2021

Vol. 15 No. 4

781--789

Bridge passing and passing waterway locks are two of the most challenging phases for inland vessel navigation. In order to be able to automate these critical phases very precise and reliable position, navigation and timing (PNT) information are required. Here, the application of code-based positioning using signals of Global Navigation Satellite Systems (GNSS) is not sufficient anymore and phase-based positioning needs to be applied. Due to the larger coverage area and the reduction of the amount of correction data Precise Point Positioning (PPP) has significant advantages compared to the established Real Time Kinematic (RTK) positioning. PPP is seen as the key enabler for highly automatic driving for both road and inland waterway transport. This paper gives an overview of the current status of the developments of the PPP algorithm, which should finally be applied in advanced driver assistant functions. For the final application State Space Representation (SSR) correction data from SAPOS (Satellitenpositionierungsdienst der deutschen Landesvermessung) will be used, which will be transmitted over VDES (VHF Data Exchange System), the next generation AIS.