M3G
Answer

M3G stands for Metadata Management and distribution system for Multiple GNSS networks. It is a software developed by the Royal Observatory of Belgium (ROB). Registered agencies can upload, validate, and distribute GNSS station metadata via the M3G website. The GNSS station metadata comprise IGS-style site log files, but also information about local networks, DOI, nominal data submissions, etc.
M3G has been developed primarily to serve the EPOS, EPN, and EPN densification GNSS networks.

Collected Metadata
Answer

  • All information included in the so-called IGS site log
  • Name of the local/national/virtual/international network in which the station is integrated
  • Data license of use
  • Embargo period on the data

Answer

If the submitted metadata is part of the metadata present in the site log, then:

  • the updated site log of EPN or EPN densification stations will automatically flow to the EPN Central Bureau. It will take up to 15 minutes for the updated site log to show up at the EPN Central Bureau web and FTP site.
  • the updated site log of EPOS stations will automatically flow to the EPOS GNSS Data Gateway.
  • the updated site log of IGS stations will have to be submitted to IGS by the Operational Centre (or station manager). M3G will not do this automatically. However, M3G will send a notification to the IGS Central Bureau informing them that the site log was updated.

Answer

M3G provide a REST (Representational state transfer) API to POST, PUT and GET GNSS metadata. For more information check the API documentation.

Answer

M3G collects data license of use and embargo period of all stations, but the information is only mandatory for the stations included in the EPOS network. EPOS stations will get the CC BY 4.0 license by default, but this information can be changed by the user. For EPN stations, the embargo period will be automatically set to no embargo period.

Login
Answer

Any agency maintaining GNSS station metadata can obtain a login account for M3G. It should be also mentioned that, by requesting and account, you also commit to maintain your GNSS station metadata in M3G. Each of these agencies (Registered Agencies) has a unique login/password.
Before requesting an account, please check if your agency has already a M3G account by browsing through the agencies here. If your agency is not listed, then contact the M3G team and provide an abbreviation of your agency that we can use as login as well as the address of your institution. As soon as the account has been created, you will receive an email.
Be aware that if the registered agency maintaining the metadata is not the same as the station owner, the station owner has to formally agree that the registered agency maintains its station metadata in M3G. For EPN or EPN densification stations, one does not need to provide M3G with the agreement. However, for EPOS stations, the data owner has to provide information on who is maintaining the metadata in M3G by submitting the EPOS-GNSS data supplier letter to the M3G team.

Answer

If you only want to retrieve metadata from M3G, you do not need an account.
Logging in to M3G is only required when inserting or updating stations’ metadata and information regarding your agency, third-party agencies, networks, etc. It is worth noticing that you also commit to maintain these data in M3G.

Answer

Your login ID is the unique identification code of your agency. You can find it in Agencies under the column Unique agency ID. If your agency is not in the list, you can request a New Account on the Login page. If you do not remember your password, use the button Reset Password. All the contacts listed in your agency will receive an email with instructions on how to reset the password.

Answer

This might be due to your spam filter or because you are not listed in M3G as one of the contacts in your agency. In the latter case, you need to contact one of your colleagues included in the contact list to ask him/her to reset the password, log in to M3G, and add you to the agency contacts.

Answer

You can access to the agency-specific tab (top right in the menu bar) and its submenus:

  • "STATION METADATA”: all information related to the stations, e.g. site log, nominal data provision, networks to which the station belongs, data licenses, etc.
  • My Agency: information on your own agency and its contact persons. New contact persons can be added by clicking on
  • Third-party Agencies: information on all agencies (and its list of contacts) involved in the operation of your stations. They can be the on-site agencies, the agencies managing the local networks to which the station contributes, etc…. New third-party agencies can be added by clicking on .
  • Managed Networks: list of all the networks that you have created in M3G. Additional networks can be added by clicking on .
Note that ALL agencies and contact persons used later on in the site log or networks, must be defined in the My Agency or Third-party Agencies submenus.

My station
Answer

  1. Login to M3G
  2. Go to the agency-specific tab (top right in the menu bar) and click on "New Station"
  3. Follow the on-line help (by clicking on the next to the title of the page)

Answer

  1. Update the site log by entering the date of removal of the equipment (Date Removed) in the most recent (i.e. last) receiver and antenna sections
  2. Save and submit the site log.
  3. Send an email to the M3G team to inform us that the station has been decommissioned.
  4. We will then switch the status of your station from ACTIVE to FORMER.
Note that decommissioned stations must not be removed from the station list of the Operational Centres because the metadata of these stations are still valuable for reprocessing historical data.

Answer

  1. Send an email to the M3G team listing the stations that will be handed over to another agency.
  2. Put the agency that will take over in copy.
The M3G administrator will make sure that the other agency has a login in M3G and will remove the stations you indicated from the list of stations for which you maintain the metadata. The M3G team will invite the other agency to add the stations to its own list.
For EPOS stations, the station owner needs to submit an updated EPOS-GNSS data supplier letter indicating the agency that will take care of the metadata management in M3G.

Answer

  • Station name (9-char ID, e.g. BRUX00BEL)
  • Network to which you want to propose the station

Answer

For security reasons, starting with M3G v1.0, users cannot remove stations anymore from the list of stations for which they maintain the metadata. If you wish to remove a station, send an email to the M3G team including also the motivation why you wish to remove it e.g. your agency is not maintaining its metadata anymore.

Answer

  1. Insert in the site log the date when the antenna and the receiver were removed from the site
  2. The station will be automatically set as INACTIVE in M3G
If you are sure the station will not become active anymore, send an email to the M3G team to inform us that the station has been decommissioned. We will then switch the status of your station from ACTIVE to FORMER.

Networks
Answer

While international and virtual networks can only be setup by the M3G administrator, a registered agency can define local or national networks in M3G, using the Managed Networks menu in the agency-specific tab (top right in the menu bar), available after login. When defining a new network, the following information is mandatory:

  • network abbreviation (must be unique throughout M3G)
  • network name
  • name of the agency that is responsible to include stations in the network (with a primary and secondary contact). The agency name is selected from a list of agencies that the user has set up already set up in M3G. This can be your own agency or another agency that has been defined as associated third-party agency.
Optionally, one can also provide:
  • the DOI associated with the network
Once the networks are defined, a registered agency can associate each of its stations with one (or more) local/national networks. For this purpose, one can select among all networks defined by M3G users.

Answer

  • EPN: Follow the Procedure for becoming an EPN station available from http://epncb.oma.be/_documentation/guidelines/procedure_becoming_station.pdf. The EPN Central Bureau will manage the status of your EPN station (proposed/included/former) in M3G.
  • EPOS: Follow the Procedure for including GNSS stations in EPOS available from https://gnss-metadata.eu/Guidelines/EPOS-GNSS_Procedure_for_EPOS_Stations.pdf. The M3G-bureau will manage the status of your EPOS station (proposed/included/former) in M3G.
  • EPN densification: M3G automatically updates the list of stations included in the EPN densification network daily based on information provided by A. Kenyeres responsible for the EPN densification network. There is no written procedure to propose stations for inclusion in the EPN densification network.

Integrate GNSS stations in EPOS
Answer

  • Your GNSS station has to be a permanently tracking GNSS station. The station can be presently active (working antenna and receiver) or it can be a decommissioned station with at least 3 years of observation data available.
  • Throughout your station’s tracking history
    • its receiver and antenna types should be included in the IGS list
    • IGS calibrations should be available for the used antennas (few exceptions are allowed).
  • You need to provide free access to daily RINEX (2 or 3) data and should agree with the EPOS open data policy .
  • You need to commit to maintain the station metadata i.e. keep the site log and additional metadata, such as antenna/radome changes, up to date in M3G.
Check out the Guidelines for EPOS-GNSS Stations, Data Suppliers, and Operational Centres, inspired by IGS and EUREF, but less strict, to be as inclusive as possible.

Answer

A detailed step-step by step guide in available in the Procedure for Including GNSS Stations in EPOS. To summarize, these are the steps to be followed:

  1. Inform the M3G team of your intend to propose stations to EPOS so that they can assist you throughout each of the steps
  2. Check if your GNSS station is suitable for integration in EPOS
  3. Make sure you are the station Data Supplier (has the legal rights on the station’s data) and decide which agency will act as Operational Centre (maintains station metadata in M3G)
  4. Set up the list of stations (with their 9-char IDs) you want to propose
  5. After consulting with the team, decide how to make your data available to EPOS and which restrictions might be applicable
  6. As Data Supplier, fill in the EPOS-GNSS data supplier letter and send it to the M3G team for feedback before signing it
  7. Make sure the appointed Operational Centre upload all agency information and the station metadata in M3G
  8. Start providing daily RINEX (2 or 3) data to the EPOS data node(s) as agreed in 4
Finally, have a look at the FAQ in this section.

Answer

The letter should be signed by the Data Supplier aka the Station Owner which is the agency that has the legal rights to distribute the data and to decide whether to decommission a station. This means that the Data Supplier does not necessarily have an account on M3G. Only the Operational Centre (OC) which by definition maintains the station metdata in M3G needs to have a M3G account. It is worth noticing that the Data Supplier is responsible for the data flow of the GNSS station to EPOS.

Answer

The Operational Centre indicated in the EPOS Data Supplier Letter, by definition, maintains the station metadata in M3G.

Answer

EPOS uses the international RINEX 3 station naming convention: a GNSS station is identified via the (9-char ID): 4-char station ID + 00 + 3-char ISO country code e.g., BRUX+00+BEL = BRUX00BEL
Be aware that the 9-char code of your station will be used for future reference (data and documentation).

Answer

You first need to select an EPOS data node and then identify eventual restrictions you want to apply to the data distribution and/or data access.

  • In particular, if your station already belongs to EPN, you do not need to select a data node as the data will be available from the EUREF node hosted at the Royal Observatory of Belgium (ROB). However, for non-EPN stations, you could set up your own EPOS data node or rely on one of the extisting EPOS data nodes. The M3G team will assist you in selected the most appropriate node for your specific case.
  • One might need to apply restrictions to the distribution of your station(s) data. It is possible to:
    • select only specific EPOS nodes (listed in the EPOS Data Supplier Letter) to distribute the station data (by default any EPOS data node can distribute the data)
    • set up an embargo time e.g. data are only made available 1.5 years after observation
    • assign a license to the station data: the Creative Commons license: CC:BY is attributed by default, but other licenses are possible (contact the M3G team).

EPOS Data Supplier letter
Answer

  • Your GNSS station has to be active (working antenna and receiver) or a decommissioned station with at least 3 years of observation data available. Be aware that the receiver and antenna type should be included in the IGS list, and only antenna calibration as well as documentation of antenna/radome changes are required.
  • You need to provide access to daily RINEX (2 or 3) data
  • You need to commit to maintain the station matadata i.e. site log and additional metadata

Answer

The letter should be signed by the Data Supplier aka the Station Owner which is the agency that has the legal rights to distribute the data and to decide whether to decommission a station. This means that the Data Supplier does not necessarily have an account on M3G. Only the Operational Centre (OC) which by definition maintains the station metdata in M3G needs to have a M3G account. It is worth noticing that the Data Supplier is responsible for the data flow of the GNSS station to EPOS.

Edit site logs
Answer

  1. Login into M3G and go to My Agency in the agency-specific tab (top right in the menu bar)
  2. Click on Modify below the contact you are interested in
  3. Change the phone number and clik on Save
The site logs of all stations listed under Used in will be updated automatically.

Answer

  1. Create a new contact by going to My Agency (or Third-party Agencies) in the agency-specific tab (top right in the menu bar) and clicking on in the upper right corner. Insert the contact name whose email you want to change, type the new email address and click on Save.
  2. Now you can use the contact with the new email address:
    • to update the email address in all the site logs whose contact information is already linked to your agency:
      Go to Link to Agencies in the agency-specific tab (top right in the menu bar), for those stations with under the preview column, change the Primary/Secondary Contact by selecting the contact with the new email address (the ones you entered in step 1). Click on Save to update all site logs. For stations without under the preview column, proceed as below.
    • to update the email address a site logs not yet linked to your agency:
      Go to Manage Site Logs in the agency-specific tab (top right in the menu bar), click on the icon (in the Export/update information column) corresponding to the station of interest, and select the contact info with the new email address. Click on Save to update the site log. Repeat this for all site logs.
  3. Delete the contact with the old email address by going again to My Agency (or Third-party Agencies) in the agency-specific tab (top right in the menu bar) and by clicking on Delete, below the section corresponding to the old contact. If the delete button is not active, it means that the contact with the old email address is still used in the site logs/networks/etc listed in the line Used in (above the Delete button).

Answer

  1. Edit, validate and submit your site log changes in M3G.
  2. After the submission, save your site log to your local disk.
  3. Go to the IGS Site Log Manager and upload the site log that you just saved.

Answer

  1. Refer to the FAQ on how to access the site log to update it.
  2. Go to the specific section and click on in the top right corner.

Answer

At present, you can only remove the most recent i.e. the last subsection of a site log. If you need to remove an older one, please send an email to the M3G team

Upload & download site logs
Answer

After login, go to the agency-specific tab (top right in the menu bar), click on Manage Site Logs. You will be redirected to a stations overview table. Click on one of the icons in the column Export/update information for the station that you are considering and follow the instructions.

Answer

You first have to assign your station to one of the international networks (EPN, EPN densification, or EPOS) that M3G is serving. Indeed, M3G needs to know which metadata validation rules are applicable. To attribute your station to an international network:

  1. Login to M3G
  2. Go to the agency-specific tab (top right in the menu bar) available after login
  3. Click on Link to Networks
  4. Once the new page loads, propose the station to at least one international network

Answer

In order to comply with GDPR, M3G is linking all the agency/contact information in the site logs with the information entered in My Agency and Third-party Agencies in the agency-specific tab (top right in the menu bar). Therefore, check the following information in the site log form:

  • Responsible Agency: you can select your own agency or one of the third-party agencies. In case you own the station, only your own agency can be selected.
  • On-Site, Point of Contact Agency: you can select your own agency or one of the third-party agencies.
  • the Primary and Secondary Contacts can be selected from the predefined contact list of the selected agency. If the contact is not in the list, click on the last item in the dropdown menu Add contact to profile and complete the information of the new contact.

Answer

You can download the content of the site logs via anonymous FTP from:

Personal data
Answer

M3G does not require personal data. It needs however contact information for the agencies that are registered or set up in M3G. This information is entered in M3G by the registered agencies themselves through the My Agency and Third-party Agencies submenus, in the agency-specific tab (top right in the menu bar). The agencies can decide to use only a public central contact information (e.g. email aliases pointing to a team). The only mandatory information is the agency name (and abbreviation), address, name of the team (or person) and the corresponding email.

Answer

Please check ROB's general privacy policy and the specific M3G privacy policy.
M3G personal data management complies with the EU General Data Protection Regulation (GDPR). Each contact person will be asked by email if he/she agrees that his/her contact information is made publicly available without restrictions. If the person declines, then his/her contact information will not be exported (in e.g. site logs) and will be replaced by the public central contact information of his/her agency (if available).

Answer

Go to My Agency in the agency-specific tab (top right in the menu bar) and delete the contact clicking on Delete. If the delete button is not active, it means that the contact is still used in a site log, a network, etc. listed in the line Used in. If the contact is used in a site log, you have to first update the site log by inserting a new contact. Once the contact that you wish to remove is not used anywhere else in M3G, the delete button will become active.

Answer

Your personal contact information has been entered in M3G. M3G then asks you if you agree to make this information publicly available without restrictions.
M3G will be sending you these kind of emails as long as you do not reply. If you decline the request to make publicly available your personal data, M3G will remove your personal data from all the metadata that are publicly available and replace it with the public central contact of your agency.

Answer

  • If your agency is registered in M3G, go to the My Agency in the agency-specific tab (top right in the menu bar), look for your name in the list of contacts, click on Ask the contact for permission/refusal button corresponding to your name and you will get a new email request from M3G allowing you to change your decision.
  • If your agency is not registered in M3G and, for example, your name has been provided as e.g. a contact person for a GNSS site, ask the appropriate registered agency to send you a new email. They can do this by logging into M3G, going to the Third-party Agencies menu, and clicking on Ask the contact for permission/refusal button corresponding to your name. You will get a new email request from M3G allowing you to change your decision.

Answer

The (unvalidated) indicates that the link between the agency/contact information in the site log (section 11/12) and the My Agency and Third-party Agencies information in M3G is missing. Consequently, M3G cannot apply the GDPR preferences of the contact persons and will have to stop distributing metadata for stations with unvalidated Responsible Agency. To solve this problem:

  • Log into M3G.
  • Go to Manage site logs in the agency-specific menu.
  • Click on the icon to Update a site log (draft/official) from data base.
  • In the site log form, the scroll down to the sections 11/12 and there select the agencies/contacts from the list that is proposed. If it is a new contact or Agency, then enter the info for the new contact or Agency.
  • If you want to save the site log without changing its name (date), then scroll up again and adapt the date prepared to keep the same date as before. If you do not mind a change of the site log name, then you can leave the date to today.
  • Finish by validating and saving.
  • For this station, the (unvalidated) will not appear in the table anymore.
  • Repeat this for all stations with (unvalidated) in the Responsible Agency column.

Answer

Yes, M3G can manage this. Proceed as follows:

  • Login
  • Go to Third-party Agencies in your menu
  • Set up a new agency, by clicking on +
  • If your station is co-owned
    • by 2 agencies X & Y (abbreviations of the agency names), then use X & Y for the Agency ID and Abbreviation (Please note: "Agency Abbreviation" can be up to 10 characters.)
    • by several agencies, then use e.g. the Consortium Name to complete the Agency ID and Abbreviation (Please note: "Agency Abbreviation" can be up to 10 characters.)
  • Fill in the address, as you would like it to appear in the site logs.
  • Insert the contact persons that you want to use in the site logs.
  • Save

To create a new station, check how to set up/add a new station

To upload the site log, check how to upload a site log of an existing station

Before validating the site log, ensure that the Responsible Agency section in the site log properly indicates X & Y or the Consortium.