Frequently Asked Questions


SiReNT Usage

  1. Why do I need the IGS code for my antenna?
  2. What kind of accuracy can I expect with the SiReNT Network-RTK (VRS) service?
  3. What kind of equipment do I need to connect to SiReNT?
  4. Apart from the GPS equipment, are there other costs involved?
  5. Can I use SiReNT for static survey?
  6. Any handy tips to validate my survey results using SiReNT?
  7. How far can I go with my roving receiver?
  8. Is SiReNT operating continuously?
  9. How long does it take to initialise with SiReNT when surveying in RTK mode?
  10. How reliable is SiReNT?
  11. Can I find out the status of SiReNT GPS reference stations while in the field?
  12. How many users can SiReNT handle at one time?
  13. Does the technology which SiReNT uses really work?
  14. Why am I unable to download certain RINEX data from PP-On-Demand?

SiReNT Admin

  1. Who do I contact for support?
  2. Where can I find out the fees for all the SiReNT services?
  3. How long must I wait for my account to be activated?

Login Difficuities

  2. Why did my password get locked?



    3. SiReNT Usage

    1.Why do I need the IGS code for my antenna?

    The IGS code is a string of numbers and letters which you enter into your reciever, so that your software can know what antenna phase centre offsets to apply. The antenna phase centre offsets enable the software to obtain highly precise GPS surveys.

    Using the correct phase centre offsets becomes very important when different antenna types are used in a survey. When using SiReNT base stations it is very likely that your antenna will be different from the antenna at the base stations. The difference in phase centre offsets between SiReNT base station antenna and your antenna need to be included in your GPS data processing. Normally this is done by your processing software.

    For more information, please read
    http://www.ordnancesurvey.co.uk/oswebsite/gps/osnetfreeservices/furtherinfo/antenna.html
    or
    here




    2. What kind of accuracy can I expect with the SiReNT network-RTK (VRS) service?

    When a VRS solution is created, you will basically have a near-zero baseline when you start the survey. Since the stated horizontal RTK accuracy spec is 1 cm plus 1 PPM of Base Line Length (vertical spec is 2 cm plus 1 PPM), the expected accuracy is better than that obtained using a normal single base station solution since we are reducing the effect of one error factor. When your roving receiver moves more than a specified distance, it will create a new VRS solution. This will keep the 1-PPM error factor to a minimum.


    3. What kind of equipment do I need to connect to SiReNT?

    a. For real-time applications, you may use any GPS equipment with DGPS or RTK capability which supports RTCM 2.3 or CMR format.

    b. If not provided as part of the GPS equipment set, a separate hardware, such as a mobile phone, might be needed to connect the GPS equipment to the internet for real-time applications.

    c. For post-processing applications, you would need a GPS equipment with data-logging capability.


    4. Apart from the GPS equipment, are there other costs involved?

    Yes. To access the DGPS data in real-time, you need to subscribe to a GPRS service. You may want to check with GPRS service providers.


    5. Can I use SiReNT for static survey?

    Yes you can. As a registered user, you may log your GPS data first during your survey and then separately access the SiReNT website to generate and download the data that you need. You may then process the static survey using your own software.


    6. Any handy tips to validate my survey results using SiReNT?

    For real-time applications, you may start your survey on a known control point (e.g ISN). This ensures that your equipment, the settings in your equipment and SiReNT will provide the results you require. You may end the day of survey by measuring on a known point as well. New technology does not eliminate the need for good survey techniques.


    7. How far can I go with my roving receiver?

    You can use SiReNT anywhere in Singapore.


    8. Is SiReNT operating continuously?

    Yes. SiReNT is operating continuously, that is, 24 hours a day, every day.


    9. How long does it take to initialise with SiReNT when surveying in RTK mode?

    Initialisation is typically shorter than 1 minute. However, this depends greatly on the environmental conditions of your survey location and the satellite configuration at the time of observation.


    10. How reliable is SiReNT?

    The SiReNT data control centre was designed with redundancy and backups, including power. Downtime, if any, would be limited to a short period.


    11. Can I find out the status of SiReNT GPS reference stations while in the field?

    Yes. The real-time status of SiReNT GPS reference stations is available on the SiReNT website. Thus, you only need to access the SiReNT website on your PDA connected to the internet to get this information.


    12. How many users can SiReNT handle at any one time?

    There is no limit on the number of roving receivers that can access the SiReNT network at any one time.


    13. Does the technology which SiReNT uses really work?

    Yes. Currently, there are already networks using this technology elsewhere.


    14. Why am I unable to download certain RINEX data from PP-On-Demand?

    PP-On-Demand only provides twelve months of RINEX data until today. For data which is unavailable through PP-On-Demand, you can request for your required data through Post-Processing Archive. In addition, Post-Processing data will only be available 1 hour after the end of the hourly-block requested time period. e.g. Data from 9am to 10am will only be available after 11am


    SiReNT Admin

    1. Who do I contact for support?

    SiReNT HELPDESK will be available to support you during the startup phase and thereafter.

    Helpdesk contact No. : (65) 6356 6546
    Operation hours of helpdesk : 8.30am - 6.00pm, Monday - Friday


    2. Where can I find out the fees for all the SiReNT services?

    The fees for PP On-Demand, RTK and DGPS can be found at Specific Terms and Conditions As each service has different fees, they can be found in the specific terms and conditions for each service.


    3. How long must I wait for my account to be activated?

    Accounts are activated within 5 working days. A notice will be sent as confirmation.


    Login Difficuities

    1. When I try to Login, the system prompted with this error meassage "Invalid user or password. Please correct your input and try again!" What do I do?

    Check you User ID and password text and format. Note: Your password is case sensitive. If the problem persists, please contact the SiReNT helpdesk for assistance or to reset your password.


    2. Why did my password get locked?

    A policy to SiReNT is expire passwords after 90 days. Users are advised to change their passwords before the 90-days deadline. Expired passwords can be reset by calling SiReNT helpdesk.



    Last Update : 27 May 2008
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