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GeoscienceAustralia / ginan

The Australian Government, through Positioning Australia (part of Geoscience Australia), is funding the design, development and operational service of a Global Navigation Satellite System (GNSS) position correction system - the Ginan service and toolkit. The application of the Ginan correction service by a GNSS device has the potential to increase positioning accuracy from meters to centimetres across Australia. The suite of software systems in this repository (the Ginan toolkit) will be used to create the service. It is available now under an open source licence. Ginan will give individuals and organisations no-cost access to the Ginan software and service as a public good.
https://geoscienceaustralia.github.io/ginan/
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Estimation of ionosphere and DCB #33

Open chuanfengzhu opened 1 year ago

chuanfengzhu commented 1 year ago

Dear Ginan term I am recently working on the estimation of ionosphere and DCB. While separating the receiver DCB and satellite DCB, I didn't find any information in the Ginan program about how the reference constraint is handled. I would appreciate it if you could explain this issue to me. Thank you very much, and I look forward to your reply.

KAHarima commented 1 year ago

Hi chuangfengzhu Thank you for your interest on Ionosphere/DCB estimation in Ginan. Short answer to your question is that Ginan fixes the DCB for a specific station to zero. This pivot station is set in one of two ways:

  1. The user can set the pivot station by designating it on processing_options -> gnss_general -> pivot_station
  2. If no station is designated (or the designated station does not have data) the pivot station is selected (in alphabetic order) from those stations with the maximum number of visible satellites. In the event of an outage on the pivot station, a new station will be selected as pivot and the DCBs will be reset
chuanfengzhu commented 1 year ago

Hi chuangfengzhu Thank you for your interest on Ionosphere/DCB estimation in Ginan. Short answer to your question is that Ginan fixes the DCB for a specific station to zero. This pivot station is set in one of two ways:

  1. The user can set the pivot station by designating it on processing_options -> gnss_general -> pivot_station
  2. If no station is designated (or the designated station does not have data) the pivot station is selected (in alphabetic order) from those stations with the maximum number of visible satellites. In the event of an outage on the pivot station, a new station will be selected as pivot and the DCBs will be reset Dear KAHarima Thank you for your patient explanation. I changed the constraint of a specific station's DCB to zero to the constraint that the sum of all satellite DCBs is zero. The resulting satellite DCBs are similar in value to the DCB products of CAS/DLR, but the calculated station DCBs are somewhat unusual in value. I am not sure if my constraint method is incorrect. Could you give me some constructive suggestions for modification? Here are some of the satellite and station DCBs that I obtained using the satellite zero-mean condition: DCB