Introduction

Accord's AutoSensorLab is a PC based software simulator of vehicle dynamics and navigation sensors. AutoSensorLab simulates the vehicle’s 3D dynamics in real time and models the behavior of GPS receiver, gyroscope and odometer. Simulated outputs are displayed on the screen, stored in files and also transmitted on the serial port in real time.
AutoSensorLab facilitates the user to configure error characteristics and behavioral idiosyncrasies of the individual sensors and study the effects on the outputs under various conditions of vehicle dynamics. The user can vary the vehicle’s acceleration, direction and altitude in real time to create a dynamic scenario for analyzing the behavior of the sensors with variations in their performance parameters. Scenarios can be recorded and replayed to use the software as a data generator.
AutoSensorLab can be a very powerful tool for software development, testing, evaluation and integration of hybrid navigation systems. It can serve as a valuable aid in the performance analysis of navigation sensors.

The AutoSensorLab has four major functional constituents:
• Vehicle Dynamics Model
• GPS Receiver Model
• Odometer Model
• Gyroscope Model

Vehicle Dynamics Model

This model simulates the 3D dynamics of the user’s vehicle in real-time. It can be initialized with 3D position, heading and speed. User can vary the vehicle’s acceleration and heading along the plane of the vehicle’s motion as well as the inclination of the plane of motion with the locally level horizontal plane. All the sensor models use the vehicle’s position, velocity and time outputs from this model. Outputs are displayed, saved in a file and transmitted on the serial port.

• GPS satellite visibility and signal blockage
• Range and Doppler measurement error characteristics
• Position and velocity computation from range and Doppler measurements
• Availability characteristics of position and velocity from the receiver The user can

configure the characteristics of various sources of error in GPS measurements like SA, ionosphere, troposphere, receiver noise, multipath etc. User can simulate non-availability of GPS signals by varying the elevation mask angles for visibility of satellites as well as by dynamically disabling/enabling satellites. Non availability of position and velocity information from the GPS Receiver can also be simulated using a random blockage model. The outputs of the model are displayed, stored in a file and transmitted on the serial port.

Odometer Model

The odometer model computes the displacement of the vehicle along the plane of motion and incorporates errors typical of an odometer. The outputs of the model are displayed, stored in a file and transmitted on the serial port. Serial output message from the model Distance traveled during the last second Gyroscope Model Gyroscope model computes the vehicle’s angular velocity along the plane of motion. Errors typical of gyroscopes such as scale factor error and bias drift are modeled. The outputs of the model are displayed, stored in a file and transmitted on the serial port. Serial output message from the model Angular velocity Resource Requirements Resource

Requirements
Serial output message from the model : Distance traveled during the last second

Gyroscope Model

Gyroscope model computes the vehicle’s angular velocity along the plane of motion. Errors typical of gyroscopes such as scale factor error and bias drift are modeled. The outputs of the model are displayed, stored in a file and transmitted on the serial port.