NOTE: This HOWTO is for Engineers using Internal Peer-to-Peer UHF radio communications for RTK.
Selecting the location for a Base Point
Use a PM (NAMRIA) or Concrete Monument where possible. If none available erect the tripod over a “known point” or select a suitable site for the Base Point where it will be easily located for future use.
Mark the point with a “PIN” 150-200mm long driven into the soil. Push the pin through a 50mm disc of aluminum foil or similar to make it easy to relocate.
Preparing the Base Receiver
Erect the tripod over the Base Point. Attach the GPS tribrach and extension pole to the tripod. Position the center of the tribrach over the PIN and level the tribrach. Install both batteries into the Altus APS-3 or APS3G base receiver, attach the UHF antenna and screw the receiver to the top of the extension pole.
Turn on the receiver. Initially the central RED LED will illuminate, then the GREEN LED will begin blinking rapidly (searching for satellites). The GREEN LED will then blink slowly. The receiver is ready……
Configuring the Base Receiver
- Turn on the Controller, select Carlson SurvCE from the Menu. From the File menu select Job.
- Create a NEW JOB (name as required – keep it short), select GREEN tick.
- Set Distance to METRIC, and Projection to UTM/WGS845/UTM Zone 51, select GREEN tick.
- Select the Equipment tab, select 2. GPS Base, Current tab, from the Manufacturer list select Altus, below the APS-3 or APS3G will display, select Comms tab.
- If the Base receiver serial number appears on the list select and select Receiver tab.
- As we leave the Comms tab the receiver will illuminate the BLUE LED, We have Bluetooth connection between the Controller and the Base Receiver.
- The settings will be retrieved from the Receiver. Set to Slant, fill in Base Receiver height (slant distance from bottom of the receiver and the top of the PIN).
- Select RTK tab, Set Device to Internal ARWest for receivers purchased before January 2015 or Internal Satel for later model APS3G receivers.
- Set Message type to RTCM V3.0, Select the “Tools icon” to the right of Device type, SurvCE will retrieve the current settings from the receiver.
- Select PLD w/EOT or PacCrest, set the Power to 1W, Set Modulation to GMSK or DBPSK, Channel Spacing 25kHz and tick Forward Error correction, write down or take a photo of the settings on a smart phone, select GREEN tick.
- Select GREEN tick. The configuration will be tranfered to the Base receiver, preparing communications for an RTK Survey!
Setting Base Coordinates
This screen shows 3 options, if working from a “known point” (ideal situation), select Enter Grid System Coordinates then type coordinates into the boxes: Northing, Easting and Height. If the data is to be used in a GIS in future we recommend a Static Survey to obtain an accurate position where NO state accuracy base points are available (see HOWTO Static Survey).
As a last resort, if the NEW base point has unknown coordinates, select Read From GPS. Set recording by the time lapse or number of positions required to average a point. The defaults are adequate to provide a point accurate to approximately one meter Northing and Easting and two to five meters in elevation/height.
Answer Yes to Continue Base setup, Save the base file configuration if required, Select GREEN tick. The Base Receiver setup is complete. The YELLOW LED is now illuminated, showing RTK data is transmitting via the Internal UFH radio.
Configuring the Rover Receiver
- Move away from the Base receiver 2- 5 meters before setting up the Rover for better UHF signal.
- Select the Equipment tab, select 3. GPS Rover, Current tab, from the Manufacturer list select Altus, below the APS-3 or APS3G will display, select the model you have.
- Select Comms tab. If the rover receiver serial number appears on the list, select it and select Receiver tab.
- As we leave the Comms tab the receiver will illuminate the BLUE LED, this indicates Bluetooth connection between the Controller and the Rover Receiver.
- The settings will be retrieved from the Receiver. Set to vertical, fill in Default Rover Pole height (1.8m). Select RTK tab,
- Set Device to Internal ARWest for APS-3 receivers purchased before January 2015 or Internal Satel for later model APS3G receivers.
- Set Message type to RTCM V3.0, Select the “Tools” to the right of Device type, SurvCE will retrieve the current settings from the receiver. Select PLD w/EOT or PacCrest, set the Power to 1W, Set Modulation to GMSK or DBPSK, Channel Spacing 25kHz and tick Forward Error Correction, check photo of the settings on the smart phone image of Base setup, making sure they are identical including the Power can be set to 100mW to save receiver battery power if working close to the Base, otherwise select higher value, (100mW = 100m, 200mW = 200m, etc.) select GREEN tick.
- Select GREEN tick.
- The YELLOW LED will be flashing (approximately once per second) if RTK messages are being received from the Base receiver via UHF radio.
Select the Survey tab, select Store Points. All systems are working correctly if the word Fixed appears in the top Left Hand Corner of the screen. If Autonomous is displayed the Base is unreachable (distance too great) or the settings for RTK are not matched perfectly (other than Power). DGPS indicated the Base data being transmitted is obstructed (HINT: raise rover pole height) or too many trees absorbing GPS or UHF signals).
Discovering Carlson SurvCE
Carlson SurvCE is a very powerful software. Developed over more than 20 years of surveyor requests and feedback, it has the capacity to record, compute and setup any survey solution in the field.
If there is a function required to perform a survey function it is available (if not let us know and we will en-devour to add it to further enhance the power of the software)….this includes staking out roads, subdivisions, pipe networks as designed on the desktop, plus surface modelling and volume calculations and GIS data collection, geo-tagging, attribution functions.
After initial understanding of the basic surveying functions (store point and stakeout) and simple processes, we recommend a detailed study of the Carlson SurvCE manual. Here step by step procedure of every function is described in detail. Always try as many functions as possible during a surveying project. During pre-survey preparation; functions should be researched, learned and tested to utilize the power of the software. Although it is not possible to learn and remember every function; familiarity makes the user a more effective, successful surveyor.
Click here to Print Setup a Base and Rover using Carlson SurvCE for the field