Describe the role of the WGS-84 gravity model in INS calculations.

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Multiple Choice

Describe the role of the WGS-84 gravity model in INS calculations.

In INS calculations, you need the local gravity vector to remove gravity influence from accelerometer measurements and to model the gravity term in the specific force as you move. The WGS-84 gravity model gives the local gravity magnitude and how it changes with position—its gradient—as functions of geodetic latitude and height above the reference ellipsoid. With that, you can compute the gravity vector in the navigation frame at the current position and use it to accurately compensate accelerometer readings and propagate gravity as you travel. Gravity isn’t constant: it varies with latitude due to the Earth's shape and rotation and with height above the ellipsoid, so knowing both the magnitude and the gradient allows precise gravity compensation throughout the trajectory. This model does not provide magnetic data, and its role isn’t about ensuring global gravity continuity for inertial alignment.

In INS calculations, you need the local gravity vector to remove gravity influence from accelerometer measurements and to model the gravity term in the specific force as you move. The WGS-84 gravity model gives the local gravity magnitude and how it changes with position—its gradient—as functions of geodetic latitude and height above the reference ellipsoid. With that, you can compute the gravity vector in the navigation frame at the current position and use it to accurately compensate accelerometer readings and propagate gravity as you travel. Gravity isn’t constant: it varies with latitude due to the Earth's shape and rotation and with height above the ellipsoid, so knowing both the magnitude and the gradient allows precise gravity compensation throughout the trajectory. This model does not provide magnetic data, and its role isn’t about ensuring global gravity continuity for inertial alignment.

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