Learning Center

How the Ditch Assist system works

The whole system on one page: where the position comes from, how it reaches the tablet, what the app works out and what the hardware does. Plus the survey, design, grade loop every job follows.

Ditch Assist® is an Android app on a tablet in the cab, plus hardware on the machine that tells the app exactly where the cutting edge is. The app does the thinking: it records the ground, designs the grade and works out how far the edge is above or below it. The hardware supplies the position and, on a Full Automation Kit, moves the implement.

The chain, start to finish

  1. RTK base

    A base station sits still on a fixed spot and sends corrections to the receiver on the machine. That is what turns ordinary GPS into a centimetre-level RTK Fixed position. The base can be your own (a second receiver on a tripod) or an RTK network over the cell signal. How RTK works.

  2. Receiver on the implement

    The receiver (rover) is mounted on the implement so it rises and falls with the cutting edge. It sends its position several times a second.

  3. The box in the middle

    On a Full Automation or Guidance Only Kit the receiver is cabled to the control module. On a DIG™ Kit it goes to the DIG module, which adds two angle sensors to find the bucket tip. With Ditch Assist Lite there is no box: the Emlid Reach on the implement talks to the tablet itself.

  4. Wi-Fi to the tablet

    The module (or the Reach) has its own Wi-Fi network. The tablet joins it and the app reads the position from it. That network has no internet, which is why you save imagery and LiDAR before you go. Connect the tablet.

  5. The app

    The app compares the position with the design and shows cut or fill. On a Full Automation Kit it also tells the control module to raise or lower, and the module drives the valve.

The same chain on each kit

Every kit runs the same app. What changes is the hardware between the receiver and the tablet, and whether the app can move the implement for you. Not sure which you have? Know your kit.

Full Automation Kit

Full Automation Kit: how the parts connect A tractor pulling a scraper with the Full Automation Kit, with numbered markers. 1: an RTK base on a tripod sends corrections to 2: the GPS receiver on a mast on the scraper, which rises and falls with the cutting edge. The receiver is cabled through the GPS breakout harness to 3: the Ditch Assist control module on the scraper tongue. The module talks to 4: the tablet in the cab over its own Wi-Fi, and drives 5: the proportional valve on the tongue, which raises and lowers 6: the lift cylinder. 7: four hoses run to the tractor remotes, one pair on constant flow for the valve and one bypass pair so the lever can still work the implement. 8: the power harness runs straight from the tractor battery, through its fuses, to the module. 12345678Wi-Fi
The receiver tells the control module where the cutting edge is, the tablet works out the target, and the module drives the valve to hold the edge on it.
  1. RTK base. Sends corrections to the receiver for an RTK fix.
  2. GPS receiver. On a mast on the scraper, so it rises and falls with the cutting edge. Its cable runs to the control module.
  3. Control module. On the tongue. Reads the receiver, runs its own Wi-Fi and drives the valve.
  4. Tablet. In the cab, on the module's Wi-Fi. The app works out the target and shows the guidance.
  5. Valve. On the tongue. Raises and lowers the implement when the module tells it to.
  6. Lift cylinder. Moves the cutting edge up and down.
  7. Tractor remotes. Four hoses. One pair feeds the valve on constant flow. The bypass pair lets the tractor lever still move the implement, without unplugging anything.
  8. Battery and power harness. Straight from the tractor battery, through the harness fuses, to the module.

Guidance Only Kit

Guidance Only Kit: how the parts connect A tractor pulling a scraper with the Guidance Only Kit, with numbered markers. 1: an RTK base sends corrections to 2: the GPS receiver on a mast on the scraper. The receiver is cabled through the GPS breakout harness to 3: the Ditch Assist control module, which sends the position to 4: the tablet in the cab over its own Wi-Fi. The tablet shows which way to move the implement, and 5: the tractor remote is hosed straight to the lift cylinder, so the operator works the lever. 6: a dashed outline labelled Valve later shows where a proportional valve goes if one is added. 7: the power harness runs from the tractor battery, through its fuses, to the module. 1234567Wi-Fi
Same control module and receiver, no valve. The tablet shows which way to move the implement and you work the tractor lever. A valve can be added later to make it a Full Automation Kit.
  1. RTK base. Sends corrections to the receiver for an RTK fix.
  2. GPS receiver. On a mast on the scraper, so it rises and falls with the cutting edge.
  3. Control module. Reads the receiver and sends the position to the tablet over its own Wi-Fi.
  4. Tablet. Shows which way to move the implement.
  5. Tractor remote. Hosed straight to the lift cylinder. You move the implement with the lever.
  6. Valve later. The dashed box is where a valve goes if you add one.
  7. Battery and power harness. Straight from the tractor battery, through the harness fuses, to the module.

Ditch Assist Lite

Ditch Assist Lite: how it connects A dozer with Ditch Assist Lite, with numbered markers. 1: an Emlid Reach RS3 or RS4 on a pole on the blade, the only part on the machine: no control module, no wires to the cab and no valve. 2: the tablet in the cab joins the Reach’s own Wi-Fi hotspot, which has no internet. RTK corrections reach the receiver one of two ways: 3: by LoRa radio from a second Reach set up as a base on a tripod, or 4: from an RTK network over the receiver’s own SIM card. 5: the operator moves the blade, following the arrows on the tablet. Wi-Fi12345
Only a receiver on the blade. Nothing else goes on the machine, and you move the blade.
  1. Emlid Reach RS3 or RS4. On a pole on the blade. The only part on the machine: no control module, no wires, no valve.
  2. Tablet. Joins the Reach's own Wi-Fi hotspot, which has no internet, and shows the guidance.
  3. Reach base. A second Reach on a tripod sends corrections by LoRa radio.
  4. Or an RTK network. Corrections over the receiver's own SIM card. Emlid Corrections over the SIM: RS4 and RS4 Pro only, not in Canada.
  5. You move the blade. Follow the guidance on the tablet.

DIG™ Kit

DIG Kit: how the parts connect An excavator digging a trench, seen from the operator’s left, with numbered markers. 1: a GPS receiver on the DIG pendulum mount at the top of the stick; the mount swings so the receiver stays level. 2: an angle sensor on the stick. 3: an angle sensor on the dogbone linkage above the bucket. Cables run over the boom to 4: the DIG ECU beside the cab, which works out where the bucket tip is from the GPS position, the two sensor angles and the link lengths measured at calibration. It sends that to 5: the tablet in the cab over its own Wi-Fi. A dashed construction line runs from the pendulum pivot down through the boom-end pin and the bucket pin to 6: the bucket tip, which the app shows against the design grade along the bottom of the trench. Wi-FiDesign grade123456
The DIG module works out where the bucket tip is and sends it to the tablet over its own Wi-Fi. The app shows depth to grade at the bucket tip; you run the excavator.
  1. GPS receiver. On the DIG pendulum mount at the top of the stick. It swings so the receiver stays level.
  2. Stick sensor. Measures the angle of the stick.
  3. Bucket sensor. On the dogbone linkage. Measures the angle of the bucket.
  4. DIG module (ECU). By the cab. Works out where the bucket tip is from the GPS, both angles and the lengths measured at calibration.
  5. Tablet. On the DIG module's own Wi-Fi.
  6. Bucket tip. The dashed line runs from the GPS pivot through the stick pins to the tip. The app compares the tip with your design grade.

What the app does, and what the hardware does

JobDone by
Centimetre position (RTK Fixed)Your base and receiver. The app can't improve a bad fix, so it holds grading when RTK is lost.
Getting the position to the tabletControl module, DIG module or Emlid Reach, over their own Wi-Fi.
Bucket-tip position on an excavatorDIG module (from the GPS and two angle sensors).
Recording the ground (survey)The app.
Designing the gradeThe app (Slope-IQ™ and the other design tools), or your land-forming design software for Land Forming.
Cut / fill, chevrons, depth guide, soundsThe app.
Raising and lowering the implementFull Automation Kit: the app decides, the control module drives the valve. Every other kit: you, by hand.
Saving surveys, designs and jobsThe app, on the tablet (Documents/DitchAssist/).

Every job is the same loop: survey, design, grade

Survey, design, grade, save and resume The loop every surface job follows, top to bottom. 1 Survey: drive the route and the app records the ground. Blade height plugs in here: it is only used while you survey. 2 Design: Slope-IQ or the workflow's design window builds the target grade. 3 Grade: the blade is worked to the target, automatically with a Full Automation Kit or by following the guide. 4 Save and resume: the job saves itself when you stop. An arrow loops from Save and resume back to Grade: on another day, calibrate on the benchmark first, then keep grading. Survey, design, grade 1 Survey Blade height 2 Design 3 Grade 4 Save & resume Next day: calibrate first
Survey the ground, design the grade, grade it, and pick the job up again another day. Blade height only matters while you survey. A benchmark matters when you come back to an older survey or design.

  1. Survey

    Drive the route with the implement raised. The app records a ground elevation every 10 ft by default (the Recording Interval setting, in the SURVEY box of Settings), taking your blade height off each point.

  2. Design

    The app designs a grade from the survey: for a ditch, Slope-IQ finds a line that always drains to the outlet with as little cut as it can. Land Forming loads a design from your land-forming design software or Geo-Surface™ instead.

  3. Grade

    Lower the cutting edge and work. The app shows how far above or below grade you are; on a Full Automation Kit it holds the edge on grade for you.

  4. Save and come back

    Surveys, designs and grading jobs save on the tablet. Coming back on another day? Calibrate to your benchmark first. Do I need to calibrate today?

Some workflows skip a step: Leveling and Manual Grade need no survey, Levee & Contour steers you along contours rather than grading. All workflows.

Related

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