GPS Attitude Determination Under Antenna Array Geometry Deformation

Alexander Kozlov,

Alexey Nikulin, Andrei Golovan, Ali Cepe, Vladimir Chemodanov

RAST 2015Moscow State University, RussiaNavigation and Control lab.

Attitude determination using GPS

Attitude determination accuracy

Antenna array deformations undeforme

d state, no rotation

observable deformation

ambiguous deformation

Antenna array deformation types

Single baseline/multiple baselines are deformed

Constant/varying deformations

Stochastic/determined deformation model

Coordinated/arbitrary deformations (multiple baselines)

Math behind the scene Baseline deformations

S defines which directions are allowed for deformations

If no inertial measurement unit (IMU) is present, the quantitive effect of deformation on attitude determination is fully defined by S and antenna array geometry

If IMU measurements are available, the effect depends on S, and antenna array geometry, and gyro measurement quality and satellite motion

No IMU, 2 antennas

No IMU, 3 antennas

No IMU, 4+ antennas

GPS/IMU data fusion, 2 antennas

GPS/IMU data fusion, 3 antennas

GPS/IMU data fusion, 4 antennas

Summary Antenna array geometry deformations can be

observable or ambiguous in terms of attitude determination

If observable, without IMU geometry of antenna array and geometry of deformation both define the accuracy of attitude determination

IMU measurements allow some antenna array geometry deformations to become observable

With IMU, satellite motion is also significant