Ephemeris state not check based on current time in real-time processing
In PPP processing, the satellite position is obtained from the applicable navigation message. There is a check on whether this message can be used or whether it should be discarded because it is unhealthy, outdated or bad-formed. However, from the current implementation, it seems that in real-time processing this status is only defined at the time the message arrives for the first time. Therefore, if a navigation message is not updated, exceeding the validity time, but the satellite is still in view, the outdated navigation message may be used.
I think that in real-time inside the PPP processing, when the getCrd function is called, it is necessary to relaunch the checkEphemeris to ensure the ephemeris saved in the database is still valid and not outdated.