How do ships, aircraft, and military land vehicles collect data for computer-based dead reckoning?

Modern computer-based dead reckoning relies on specialized computers to process streams of directional, speed, and timing data to estimate a vehicle's current position. These systems often employ Kalman filtering to mathematically combine multiple data sources for the most accurate estimate.12

Data collection methods vary by vehicle type:

• Ships: Navigators typically utilize a gyrocompass for direction and a log to measure speed through the water.2
• Aircraft: Systems rely on gyromagnetic compasses and Doppler-effect sensors to determine velocity.2
• Military Land Vehicles: Computers are fed data from compasses and wheel-mounted sensors.2

Additionally, many modern platforms use an inertial guidance system, which employs gyroscopes and accelerometers to continuously monitor acceleration and turning rates. The computer performs numerical integrations on this data to calculate velocity and position. Because these systems accumulate errors over time, they are frequently reinitialized using external references like the global positioning system.324