ar

7 Series AR Example (C)

This example demonstrates how to configure the attitude filter to stream filter data on a MicroStrain 7-series AR device with the MIP SDK using the C API.

Overview

The example showcases the basic setup and operation of a 7-series AR device, including:

• Device initialization and communication
• Filter message format configuration
• Gyro bias capture
• Filter initialization
• Real-time data streaming and display

Configurable Options

The example uses the following default settings, which should be adjusted based on application requirements:

Setting	Value	Description
PORT_NAME	"COM1" (Windows) "/dev/ttyACM0" (Unix)	Serial port for device communication
BAUDRATE	115200	Communication baud rate
SAMPLE_RATE_HZ	1	Data output rate in Hz
RUN_TIME_SECONDS	30	Example runtime duration

Usage

1. Connect your 7-series AR device to the specified serial port
2. Update the configuration options based on your application needs
3. Compile and run the example
4. Follow the gyro bias capture prompt (keep the device stationary)
5. The program will:
   • Initialize the device
   • Configure data streaming
   • Wait for the filter to reach vertical gyro mode
   • Stream data for the specified runtime
   • Display filter state transitions
   • Display real-time filter data
   • Clean up and exit

Building

With CMake (Recommended)

The project can be configured on its own using the supplied CMakeLists.txt. The file is configured to work directly in the MIP SDK project or as a standalone project. If building outside the MIP SDK project, all that's needed is to define MIP_SDK_ROOT_DIR. When building within the MIP SDK project, make sure to enable the examples using the MICROSTRAIN_BUILD_EXAMPLES CMake option.

Standalone Command Line

mkdir build
cd build
cmake .. -DMIP_SDK_ROOT_DIR:PATH=<path_to_mip_sdk>

Without CMake

If the project cannot be configured using CMake, then the following project configurations are required:

Required Libraries

Link against these libraries:

• mip - Core MIP SDK library
• microstrain - Core MicroStrain SDK library
• microstrain_serial - MicroStrain serial communication library

Make sure to include those library paths as additional link directories if needed

Include Directories

Add these include directories:

• [path_to_mip_sdk_include]/c
• [path_to_project_root]

path_to_mip_sdk_include can be installed paths or source paths:

• Unix - /usr/include/microstrain
• Windows - C:/Program Files/MIP_SDK/include/microstrain
• Source: [mip_sdk_project_root]/src

Compiler Definitions

Add these compiler definitions:

• MICROSTRAIN_LOGGING_MAX_LEVEL=MICROSTRAIN_LOGGING_LEVEL_INFO_ Sets the logging level to info which is the minimum required for this example

Key Functions

Device Setup

• initialize_device() - Establishes communication, validates device connection, and loads defaults
• capture_gyro_bias() - Captures and applies gyroscope bias compensation
• initialize_filter() - Initializes the attitude filter

Message Configuration

• configure_filter_message_format() - Configures filter/attitude data output including:
  • GPS timestamp
  • Filter status
  • Euler angles (roll, pitch, yaw)

Data Display

• display_filter_state() - Displays navigation filter operating mode changes

Communication Interface

• Uses the mip_interface struct for device communication
• Serial connection handled by serial_port

Data Handling

This example demonstrates traditional C programming patterns:

• Manual Parsing: Direct parsing of incoming MIP packets using the MIP parser
• Callback Functions: Function pointer-based callbacks for data processing
• Explicit Memory Management: Manual buffer and resource management
• Type Safety: Uses C structs and enums for data type safety
• Error Codes: Command results handled through return codes and error checking

C Implementation Features

This example showcases:

• MIP Interface: Core C interface for device communication (mip_interface)
• Serial Port Management: Low-level serial port operations
• Parser Integration: Direct use of the MIP packet parser
• Memory Safety: Careful buffer management and bound checking
• Portability: Cross-platform compatibility (Windows/Unix)

Custom Communication Functions

The example implements custom communication handlers:

• Send Function: mip_interface_user_send_to_device() handles outgoing data
• Receive Function: mip_interface_user_recv_from_device() manages incoming data
• Timeout Handling: Configurable timeouts for reliable communication

Filter Data Output

The example streams the following filter data:

TOW Data

• Units: seconds
• Description: Time of Week - GPS time reference
• Format: Floating-point timestamp value

Euler Angles Data

• Units: radians
• Description: Orientation expressed as Euler angles
• Format: [Roll, Pitch, Yaw] angle vector

Streaming Output Format

The example displays filter data in the following format:

TOW = 123456.789     Euler Angles = [ 0.012345, -0.067890,  1.234567]

Filter State Progression

The example monitors and displays filter state transitions:

1. Startup - Filter startup
2. Initialization - Filter initialization
3. Vertical Gyro - Basic attitude estimation
4. AHRS - Full attitude and heading reference
5. Full Navigation - Complete navigation solution with position/velocity

Error Handling

The example includes comprehensive error handling with:

• Command result checking using mip_cmd_result
• Connection failure detection and recovery
• Graceful termination functions for different error types
• Detailed error messages with context

C Features

This example demonstrates:

• Standard C11 programming practices
• Minimal external dependencies
• Direct hardware interface programming
• Efficient memory usage patterns
• Cross-platform serial communication

Requirements

• MicroStrain 7-series AR device (3DM-CV7-AR or 3DM-GV7-AR)
• Serial connection (USB or RS-232)
• MIP SDK library with C support
• C11 or later compiler

See Also

• C++ version: 7_series_ar_example.cpp
• Other examples in the examples/ directory
• MIP SDK documentation