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Multi-purpose navigation board

Multi-purpose navigation unitCustomer

Russian manufacturer of marine electronic equipment.

Objective

The objective was to develop a multu-purpose navigation board, capable of organizing longitudinal motion, dynamic positioning and automatic mooring of vessels.

Another task was to perform stand and field testing by using a complex of mathematical modeling and simulating automatic and semiautomatic vessel control systems.

A specific requirement to the device was its capability of being easily integrated into existing vessel control systems.

Solution

Hardware

Our specialists developed a schematic on the basis of STM32F103VB microcontroller with ARM Cortex-M3 architecture. They implemented a parallel interface with LCD display with resolution 240õ128 and built-in T6963c controller. It displays ship’s motion according to the specified fairway.

They also implemented interfaces for connecting steering sensor, SD/MMC memory cards, FRAM, connection schemes for CRS03-02, BG910, ADIS16250 gyroscopes, membrane keyboard, three-position manipulator, LED indicators and buzzer.

To ensure high integrability the device was equipped with a range of RS-232 interfaces that can be used to connect satellite navigation system (GPS), gyrocompass and other external navigation devices via NMEA 0183 protocol. Also, the device has a possibility to be automatically connected to reserve power supply and a possibility to connect analog inputs and outputs.

STM32 ARM Cortex-M3 board

Analog outputs of amplifiers and RS-232 interfaces are secured with the required galvanic isolation with the help of ADuM2400 and ADM3315 chips.

To increase the reliability of the device, our engineers added the protection of feed circuits against polarity reversal and short circuit, and also developed the system for automatic switch to reserve power supply without loosing device’s operability with detection by microcontroller. They also implemented galvanic isolation of main and reserve power supplies.

Design and ergonomics

Our designer developed an attractive design of membrane keyboard at front panel of the device in cool colors. All captions are in large font, easy-to-read and are intuitively associated with their indexing areas.

The designer took into account usability of the device in specific conditions of exploitation throughout the design of joystick location, buttons, their sizes and purposes.

On the development stage, the designer suggested several solutions of membrane keyboard designed in different colors and different control locations.

Front panel for navigation board

Case and construction

The construction was implemented on the basis of ready case made by BOPLA. During the device’ construction design, the designer ensured the mateability of several objects:
  • LCD display;
  • Digital module board;
  • Front panel of the case;
  • Membrane keyboard;
  • Analog module board;
  • Controls;
  • External connectors.
Our specialists created 3D-models and arranged all modules in the case to ensure optimal location of connectors both inside and outside the case, convenience of assembly during production and during testing process.

For the convenience of assembling-disassembling the digital board is secured to front panel and is connected to other equipment by means of detachable connectors. For this purpose the design of digital module considers the location of controls on front panel.

A peculiarity of device’s construction is the inclined position of analog board inside the case. It is connected with a necessity of balancing assembly angle to allow aligning of gyroscope relatively to horizontal plane.

Navigation unit assembled

The appeared construction tasks were solved with the help of combination of development tools EDA – MCAD. This allowed operative modelling of the design without stopping the PCB design process: changes in PCB layout were automatically displayed in their 3D-models, joined in a single construction.

Software

To demonstrate the work of the periphery and the device in whole, our engineers developed software for real-time operating system – freeRTOS.

They also wrote drivers for eight-channel AD7927 analog-to-digital converter, two-channel AD5323 digital-to-analog converter, ADIS16250 gyroscope chip, T6963c graphical display controller and FM25L256B nonvolatile memory.

Engineers developed a graphical library to work with graphical display. The library has got a convenient system for connecting required fonts, both monospace and proportional, that positively affected the ergonomics.

freeRTOS graphical user interface

The team of engineers implemented support of FAT32 file system or SD/MMC card, wrote procedures for working with event logger located in FRAM, implemented modules for working with RTC, adjusting brightness of display light and self-diagnostics module. Thee also provided a configurable support of NMEA protocol for connecting an external GPS device and gyrocompass. Besides, they added a possibility for on-board programming and updating software without opening device’s case.

Benefits

  • A principal platform, on the basis of which it is possible to quickly develop a range of other water transport electronic devices: gyropilot, ship’s swing speed sensor, control panels, etc.
  • The developed device possesses a huge potential of being used in various spheres of water transport control.
  • High integrability into existing ship control systems.
  • Application of modern microcontroller with ARM Cortex-M3 architecture.
  • Application of RTOS allows flexibly extending the range of performed tasks.

Technologies FSTN LCD, SPI, UART, RTOS, FRAM, SD/MMC
Programming languages C, Python
Development tools GCC, EDA, CAD
Project management tools SVN, dotProject, Mantis
Labor input 140 man-days
Project completion period 5 months