RTK-GPS Iowa

Frequently Asked Questions

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When is the network going to be operational?

The target date for acceptance of the network is Dec. 1, 2008. The Iowa DOT will periodically update the network schedule on this Web site.

What does it cost to use the network?

There are no current plans to charge users, whether from the public or private sector, to access the network.

Is there an access charge for RTK usage?

There are no current plans to charge RTK users, whether from the public or private sector, to access the network.

Do I need to register to use the network for RTK surveying?

All RTK users of the network are required to register with the Iowa DOT. Additional details on the process for registration will be provided at a later date.

What type of communication equipment is needed for RTK access?

An internal or external rover cell modem or a data-capable cell phone with the ability to communicate with your rover and the Internet are needed to access the network corrections.

What type of cellular service do we need for RTK access?

Any GSM (Global System for Mobile Communications) or CDMA (Code division multiple access) data-cellular service will work with the network. An unlimited data plan is highly recommended.

What cellular service provider do we need to use?

We canít recommend any particular cellular provider. Cellular-data coverage at the location where you will be surveying is the most important consideration in choosing your cellular provider.

What brand of GPS rover is needed for RTK surveying?

Any brand of GPS rover of recent manufacture capable of receiving RCTM 2.3, 3.0, 3.1, CMR, or CMR+ messages is required. In addition, current firmware allowing connection to cellular communications, and a cellular modem or data-capable cell phone, are required. Consult with your roverís local distributor for questions specific to your equipment.

Will the data from individual stations be available online?

RINEX data from individual stations will be available online for post-processing. The Iowa DOT plans on providing the user with RINEX data sets in user selectable time frames from one hour to 24 hours, with user-selectable sampling rates of 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30 and 60 seconds. Specific information regarding sample rates, and length of time data will be available online. Procedures for requesting and downloading data will be available prior to the network coming online.

Can smaller sampling rates be provided for specific projects?

Yes, upon prior request to the Iowa DOT, data is available with a sampling rate as small as 0.1 seconds. If we are aware of your needs before hand, a project-specific file can be created with a sample rate to meet your needs. Details on how to request this data will be made available when you register as a user of the network.

Can only dual-frequency, survey-grade rovers receive real-time correctors?

No, the network also provides single - frequency correctors suitable for use by professional quality mapping/GIS grade, single-frequency GPS receivers capable of using a cellular data modem or a data-capable phone to receive RTCM (Radio Technical Commission for Maritime Services) messages.