Cell Phone/Modem FAQ's Print E-mail

Cell Phone Outages: Can-Net has a strong relationship with the major cell phone providers in Canada. Cell phone interruptions and outages that directly affect Can-Net users will be posted at all times whenever possible. GNSS correction data streaming is unique in cellular applications since it needs the data stream to be reliable and fast. Most data cell activities, emailing, text messaging, even video streaming utilize data buffering and re-sending lost data packs. True real-time data streaming is only necessary in GNSS corrections. Re-sending a lost data pack Data Notifications affecting Can-Net users will be posted only when the interruption directly affects Can-Net user as it applies directly.

Cell Phone/Modem FAQ

This FAQ was developed from real questions posed by a new customer. The response will assist in understanding what role the phone plays and also what type for phone should be selected.

Q: I assume that the rover in the field connects to the cell phone via Bluetooth, then uses the cell phone data stream to talk to your Cansel network servers over the internet. Is that assumption correct?

A: More specifically it is the Data Collector (not the GPS receiver) that connects to the cellphone via Bluetooth. The data collector also connects to the GPS receiver and then facilitates the position corrections, field data collection, and other survey applications (stake out, cogo, etc). The Data Collector is running Windows Mobile 5 and thus handles the Bluetooth connections and the internet connections. It uses the WM5 functions which can be configured with inside the Trimble Software, Survey Controller or within the WM5 operating system. It's just a few clicks and parameters to setup a "Phone Profile"

Q: Does the cell phone connect to your Cansel servers using the "mobile browser" (web browser) that is built into the phone? If not, what application does it use? Is there a custom Cansel application loaded onto the phone to make this connection?

A: The phone is acting as a modem, a totally wireless Bluetooth modem. The phone must be Dial-Up Networking (DUN) compatible and thus does not use the "mobile browser" function directly on the phone. But most phones that have a Mobile browser and Bluetooth are more likely to be DUN compatible. So it is the data collector and WM5 that handles most of the internet connectivity and the phone is just acting as modem. Once the gateway to the internet has been establish many functions are enabled. The WM5 makes the DUN connection to the phone, thus it is the web browser on the data collector that can surf the web (or email, or ftp). The gateway to the internet then enables a specific utility that uses NTRIP (Network Transportation of RTCM Internet Protocol) to deliver GPS Corrections from a specific IP address ntrip.can-net.ca and port 2101/2102(Western/Eastern Canada). Sounds complex, but its just a few clicks and pre-set parameters to make it all happen. When configured, you simply "Start Survey", the phone gets the information to start the modem dial-up, a source table of GPS corrections is created, click on PNTC_CMR+ for your specific corrections, enter a UN/PW authentication for the data, data starts streaming.... initialization gain.... poof! 1cm level accuracy.

Q: I am asking these questions as I am trying to make sure that we get a cell phone that is going to meet all of the requirements of your system. Based on some of the phone models included in your graphic, like the Samsung A950, I am assuming that the phone only needs to have Bluetooth and mobile browsing capability to work with your system. Please confirm this.

A: It does need to be DUN compatible or sometimes they might refer it to be just "modem" compatible. Since it is a rarely used function some cell phone retailers might not know it the phone has that function. If possible see if it can be tested prior to committing to that phone. If it is Rogers then the SIM card can be switched to different phones. You also need data account (no voice account is required) usually <50Mb is typical use. The maximum is 100MB/mo if working 5days x 8hrs.