Alignment determination and error characterisation of inertial components for use in an airborne gravimeter

An airborne gravimeter utilising a gyro stabilised platform is being developed. The accuracy requirements of the system require inertial grade accelerometers and gyroscopes to be used to allow changes of less than a micro g to be detected. Three Q-Flex quartz pendulous type accelerometers are maintained in a local level orientation using two CSG-2 two degree of freedom tuned rotor gyros.;Phase I of the testing involved demonstrating the suitability of the inertial instruments for use in the gravimeter. The error terms were defined and determined by using a precision inertial test table to apply rates or accurately position the instruments. Resolution and temperature dependence were also determined.;Phase II involved mounting the instruments in a inertial sensor block. Model equations were developed to define the gyro and accelerometer outputs. Static testing and autocollimation determined the misalignment angles and the major error terms of the instruments. Lab techniques used in inertial testing are discussed, as are the steps taken to reduce errors.