CAJ | 학술논문

日本SELENE的两个小卫星Rstar和Vstar都搭载两个晶振作为VLBI多频点信标源的基准，其中一个晶振产生信号f1，另一个晶振产生信号f2和f3。通过分析Rstar 和Vstar 的同波束VLBI 观测数据，发现利用来自异源的两对频点信号(f1, f3)的相关相位解算差分时延时，由差分频率与仪器时延差相乘所引起的相位误差较大，从而导致差分群时延的精度不高以及差分相时延的实时解算成功率不高。利用来自同源的两对频点信号(f2, f3)的相关相位来求解差分时延，与利用异源信标相比，上述误差值为原来的1/64，使得差分群时延精度提高，差分相时延实时解算成功率也大幅提高。分析结果表明，若把台站间的仪器时延差(包括钟差)修正至1μs时，将有望进一步提高差分相时延的解算成功率。基于上述分析结果给出了适宜于同波束VLBI观测的同源信标源设计方案。
일본SELENE적량개소위성Rstar화Vstar도탑재량개정진작위VLBI다빈점신표원적기준，기중일개정진산생신호f1，령일개정진산생신호f2화f3。통과분석Rstar 화Vstar 적동파속VLBI 관측수거，발현이용래자이원적량대빈점신호(f1, f3)적상관상위해산차분시연시，유차분빈솔여의기시연차상승소인기적상위오차교대，종이도치차분군시연적정도불고이급차분상시연적실시해산성공솔불고。이용래자동원적량대빈점신호(f2, f3)적상관상위래구해차분시연，여이용이원신표상비，상술오차치위원래적1/64，사득차분군시연정도제고，차분상시연실시해산성공솔야대폭제고。분석결과표명，약파태참간적의기시연차(포괄종차)수정지1μs시，장유망진일보제고차분상시연적해산성공솔。기우상술분석결과급출료괄의우동파속VLBI관측적동원신표원설계방안。
Rstar and Vstar are two satellites of Japanese SELENE pro ject, each carries two crystal oscillators on board as the sources of VLBI signals, one generates frequency f1, the other generates frequency f2 and f3. Analysis of the VLBI same-beam data from Rstar and Vstar shows that much phase error was generated by differential frequency multiplies differential instrumental delay, when using the correlation phases of frequency f1 and f3 to resolve differential time delay, thus the accuracy of differential group delay was impaired, and the chances of successfully resolving differential phase delay were low. This paper shows the error mentioned above can be reduced by 64 times, when using the correlation phases of frequency f2 and f3 to resolve differential time delay, this improves the accuracy of differ-ential group delay comparing to the first method, and increases the chances of successfully resolving differential phase delay. In addition, this paper shows if instrumental delay (in-cluding clock offset) between each two VLBI stations are to be corrected to 1 micro-second level by observing quasars, the chances of successfully resolving differential phase delay can be improved further. We also present a design of onboard radio sources, which is suitable for same beam VLBI observations.