Vscan acquisition software, developed in-house and refined over several years, allows the use of a variety of sensors, Laser scanners and IMU’s.
The Vscan screen is designed to inform you at a glance by graying out the displays that fall within acceptable limits. The original version of Vscan was developed for an 800X600 screen. Since then it has evolved into a 1024X768 display resolution to accommodate Laser Ethernet communications and a laser profile display.
Use the tutor by opening it in its own browser window. Click on any part of the screen for more information or on the green Vscan icon (top left) to display the home page.
What’s Inside the Controller?
The expensive part of the controller is a Novatel OEM-V3, a survey-grade GPS receiver that allows integration of the Inertial Measurement Unit data. When power is first applied to the system, via GND or AIR breakers, it is gated with high current schottky diodes to prevent battery interaction. Both breakers can be depressed at the same time but it is good practice to take the unused battery completely off-line after switching from external power to the aircraft power.
The 24V -28V power input is conditioned to reduce periodic and random deviations and distributed to internal supplies for the Panasonic Toughbook computer, docked on the controller, a high current 24v/12v converter and to connectors for peripheral equipment power. The same rail is provided to the Laser Scanner via the 10A breaker. (The only internal 12V requirement is for the Novatel SPAN system.)
The IMU is an IMAR/FSAS and connects to the controller with an RS-422 protocol. This can only be done on COM1:, so the IMU must ALWAYS go to that port. (Com1: Is the top, right DE-9 connector, viewed from the back. Com2: is directly underneath it, with Com3: to the left of Com2: and the female I/O de-9 at top-left) Space on the rear panel is at a premium, and the IMU connector is a tight fit.
Connections are straightforward, aside from the Com Ports.
Novatel SPAN dual frequency GPS receiver and Inertial Processing System (A White Paper)
Securing the controller-If no passenger in rear, seat belt should be on top of Toughbook with cover closed.
- Before each flight check and clean the laser window(s) to ensure cleanliness. Light pressure with a soft cloth and residue-free cleaner if required. You can make your own lens cleaner – safe on all types of lens. 60% Isopropyl Alcohol, 40% clean water, a tiny drop of dish detergent per 50 ml of solution. Mix well and use in a spray bottle. The detergent adds surfactants that help reduce fogging.
- If laser returns are lost after lift-off, the likely problem is dirt picked up by the laser window. It will be necessary to land and clean the window.
- A good practice: Keep the radio switch off on the Toughbook. This prevents any wireless Internet activity, as none is required.
- GPS Rollover – Saturday midnight: GMT – don’t fly through it.
- DOP (Dilution of Precision) : 2.0 or less is good, greater than 3.0 is unacceptable.
- If used properly, mission planning software can have you in the air when GPS quality is highest. (Or on the ground while satellite geometry is unfavourable for your area.)