Getting Started with Inertial Explorer

This section provides step-by step procedures on how to process data in Inertial Explorer.

Data Collection

Prior to data collection, NovAtel SPAN users are encouraged to review the SPAN Data Logging for Inertial Explorer application note. This reference will help ensure all required and recommended logs are requested.

In order to realize the full benefits of GNSS+INS post-processing, every survey must include an initialization and convergence period. During this period, initial conditions are computed (initial position, velocity, and attitude) and IMU biases converge and stabilize. If an IMU outage occurs before the end of this initialization and convergence period, you will not see expected performance from your system. Ideally, this initial data should be collected with a reasonably open view of the sky, and the same field procedures that are observed at the start of the survey should be mirrored at the end for the benefit of reverse processing. Regardless of the quality of the IMU, here are general data collection recommendations:

  • Start your survey with 2 to 3 minutes of stationary data collection. This will serve as a warm-up period for the GNSS and IMU and can be used directly for static alignment for systems that are capable of this.

  • Move straight and level along the forward-pointing axis of the vehicle for approximately 10 seconds. This data will be used in kinematic alignment should the static alignment fail, or if your system is not capable of static alignment. Assumptions are required in kinematic alignment in regards to the initial direction of movement, and it is also assumed that no significant roll or pitch is occurring.

  • Collect 2 to 5 minutes of kinematic data with heading changes. Do not observe repeated, tight turns with high angular rates. It is recommended to observe similar dynamics during this period as you expect to experience during your normal survey. During this period, IMU biases converge and stabilize to provide you optimal performance for your system.

  • Preform your survey.

  • Repeat the initialization and convergence steps in reverse order.

Data must be logged during the entire alignment procedure so that it can be used during post processing.

We also recommend review of the following application notes: