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Abstract

In precise orbit determination (POD) for GNSS satellites, the solar radiation pressure (SRP) that is the largest non-gravitational acceleration is a major error source. Usually, we correct SRP by using the empirical model in POD, but it is not enough. The Japan Aerospace Exploration Agency (JAXA) has been proceeding the research and development of the high-precision accelerometer that can be mounted on a satellite and measure non-gravitational acceleration directly to use acceleration data for POD. For Quasi-Zenith Satellite System satellites, the maximum acceleration caused by SRP is about 10^-7m/s², and the accuracy of JAXA's SRP model is order of 10^-9m/s². To improve the correction accuracy of non-gravitational acceleration, we need to the accelerometer which has a measurement resolution of 10^-10m/s² or less. Our goal is to improve the accuracy of non-gravitational force model by an order of magnitude. Therefore, we have been making the prototype of accelerometer that consist of the interferometric sensor, test mass, and actuator. In particular, we adopted the quadrature laser interferometer which has the advantage of both high sensitivity and wide measurement range for the interferometric sensor. Last two years, we have made the interferometric sensor and a part of the test mass and have evaluated their performance. Currently, we have been making multiple breadboard models (BBMs) of the accelerometer. By simultaneously measuring by multiple BBMs, we are planning to eliminate common-mode noise such as ground motions and evaluate their performance. In this presentation, we explain overview and status of this R&D.