Personal Inertial Navigation System (PINS)

Project Goals

• Create an integrated inertial measurement unit (IMU) and three-axis magnetometer that can be mounted at the level of the boot.

• Create software for processing the IMU data such that the pauses between each step and the next are identifiable (identifying zero velocity).

• Create software that regards each step as a separate mini-trip with its own mini-initialization. Combine these mini-trips into a single trip. (Using zero velocity observations to update the navigation calculations is known as Zero velocity UPdaTing, or ZUPTing.)

• Demonstrate that the achievable overall accuracy is useful for some military purposes. The initial accuracy goal is an error growth rate not greater than about one foot per minute.

• Integrate the PINS IMU with the Battelle Advanced Binocular System using BBN BodyLAN.

Accomplishments

• Zero velocity has been reliably detected by an algorithm operating on the IMU data stream.

• ZUPTing has been shown to work as expected, thereby enabling major reductions in the error growth rate.

• Computational accuracies using a COTS IMU, without using any magnetometer data, are approaching the near-term accuracy goal (within a factor of 2). (The COTS IMU is too big and too heavy for fielding.)

• A small, light, low-powered IMU/magnetometer ("PINSPak") has been designed and is in PCB layout (5/12/97).

• A third iteration of a boot mounting for the IMU/magnetometer has been designed and is now being fabricated.

Milestones
Near Term
Within the term of the contract

• Demonstrate the validity of the ZUPTing idea as an enabling technology for on-foot personal inertial navigation.

• Demonstrate a means for mounting the IMU at boot level that is operationally feasible for the wearer while still accurate enough for useful navigation.

• Create an IMU using COTS sensors that is acceptably small, light-weight, low powered, and accurate.

• Demonstrate the user's navigation via a display carried by the user.

Long Term
Beyond the term of the contract

• Integrate the PINS system with a GPS system.

• Integrate the PINS system with a communication link so that the movements of the wearer are known immediately by others remote from the wearer.

• Include site-specific geographic/geometric information as part of the data processing steps so that the user's calculated movements are consistent with known physical constraints.