Investigating scale factors of radiation pressure accelerations of SLR satellites

<p><span><span>For low Earth orbit satellites, the atmospheric drag is the largest non-gravitational force. With increasing satellite altitude, the acceleration due to the Earth radiation pressure </span></span><span><span>(ERP) </span></span><span><span>decreases, </span></span><span><span>whereas the effect of the Solar radiation pressure </span></span><span><span>(SRP) </span></span><span><span>becomes prevalent. </span></span><span><span>Models of these </span></span><span><span>non-gravitat</span></span><span><span>io</span></span><span><span>nal forces are </span></span><span><span>applied in satellite gravimetry, thermospheric density estimation, and</span></span><span> </span><span><span>in</span></span><span><span> precise orbit estimation of the spherical satellite laser ranging (SLR) satellites. </span></span></p><p><span><span>In earlier investigations, we found that </span></span><span><span>estim</span></span><span><span>ating </span></span><span><span>systematic errors in radiation pressure </span></span><span><span>force </span></span><span><span>models </span></span><span><span>appears possible based on an inverse procedure using GRACE data. </span></span><span><span>Our preliminary results show that </span></span><span><span>the </span></span><span><span>outgoing radiation from CERES SYN data is too small for both longwave and shortwave </span></span><span><span>data</span></span><span><span>. </span></span></p><p><span><span>Here, we want to test the suitability of another approach to obtain estimates for correcting </span></span><span><span>existing</span></span><span><span> radiation data. In this method, </span></span><span><span>we </span></span><span><span>focus </span></span><span><span>on the estimation of sca</span></span><span><span>le</span></span><span><span> factors for radiation pressure accelerations </span></span><span><span>of </span></span><span><span>different </span></span><span><span>SLR satellites </span></span><span><span>with the long-term aim to obtain corrections for existing radiation datasets</span></span><span><span>. </span></span><span><span>D</span></span><span><span>uring </span></span><span><span>the precise orbit determination </span></span><span><span>procedure </span></span><span><span>of the sph</span></span><span><span>e</span></span><span><span>rical SLR satellites, </span></span><span><span>t</span></span><span><span>he scale factors are </span></span><span><span>commonly estimated with a vari</span></span><span><span>e</span></span><span><span>ty of other param</span></span><span><span>e</span></span><span><span>ters</span></span><span><span>.</span></span><span><span> Here</span></span><span><span>, we test different parametrizations of the scale factors of both ERP and SRP accelerations and their behaviour for different SLR satellites such as </span></span><span><span>Stella and Ajisai </span></span><span><span>during varying solar conditions</span></span><span><span>. </span></span><span><span>Besides the separate estimation of scale factors for ERP and SRP accelerations, we will estimate</span></span><span><span> global (monthly) scale factor</span></span><span><span>s</span></span><span><span> for ERP </span></span><span><span>accelerations </span></span><span><span>from </span></span><span><span>a variety of </span></span><span><span>SLR </span></span><span><span>satellites. </span></span><span><span>Finally, </span></span><span><span>we will investigate </span></span><span><span>the </span></span><span><span>potential</span></span><span><span> of </span></span><span><span>the resulting </span></span><span><span>scale </span></span><span><span>factors</span></span><span><span> to correct existing radiation datasets </span></span><span><span>in the future.</span></span><span> </span><span><span>At this stage, a comparison to our preliminary estimates </span></span><span><span>from </span></span><span><span>our previous investigations </span></span><span><span>turns out as</span></span><span><span> helpful.</span></span></p>