Our system consists of a Leica Disto A6 distance meter and CaveSniper - an electronic compass integrated with a tilt sensor (or clinometer).
CaveSniper is equipped with an easy-to-read LCD display with backlight, a hermetic button (easy to use even when wearing gloves) and a laser pointer (never point the laser at one's eyes!!!). The casing is made of aluminum and is not hermetic. When inside the cave, one should take care of this measuring system just as one would take care of a gidital camera.
The integrated electronic compass measures the azimuth in any position ("upside-down" as well), although for most precise results try to keep it within ±60 degrees tilt. When the inclination is higher, the error margin increases slightly.
All distance readings are transmitted from the Leica distance meter to CaveSniper via Bluetooth. CaveSniper's integrated memory is used to store all the results; it will hold up to 4000 readings. Thanks to using the Flash memory chip, all data is saved even when the battery discharges completely.
CaveSniper is operated with a single button! While a short presses toggles between various display modes, a longer press (0.5 second or longer) is used for a measurement. A 3-line CaveSnipper's LCD display shows the latest measurement. A short press will take you to another screen showing the vertical and horizontal components. Another press will show you the rotation angle of CaveSniper along its axis (this info is necessary for the measurements), as well as the inclination measurement, temperature and battery level. The next screen is used to save the latest measurement (Save point). A long press saves the last measurement to the internal memmory (you can delete it anytime in the service mode discussed later). The last screen is used to save an additional LRUD (left, right, up or down).
In the basic mode, the following screens can be accessed with a short press of the button:
When using our system, your LRUDs do not have to be "classic", i.e. you do not need to limit yourself to saving classic lefts, rights, ups and downs. Simply point the CaveSniper in the required direction and save the additional measurement as a LRUD. In a slanting crack, simply point the CaveSniper at e.g. 45 degree angle and your additional measurement will have its own lenght, azimuth and tilt saved in the memory. When importing the data from CaveSniper to your PC you can decide whether you want to keep your LRUDs in this new format or whether have them automatically recalculated to classic LRUDs. Note this new format gives you more information on the characteristics of the cave. All LRUDs are saved in CaveSniper as a letter following a collon, e.g. 14:A 14:B
A quick start guide
Turn your Leica distance meter and press its Bluetooth button and then turn the CaveSniper on. After a few seconds both devices will "beep" and CONN will be displayed on CaveSniper's LCD. This means both devices are linked via Bluetooth and ready to use. Measure the distance with the Leica distanc emeter and press the Bluetooth button - the measured distance will be sent to CaveSniper and will be displayed on its LCD. Next measure the azimuth and tilt with the CaveSniper by pressing and holding the button, pointing in the required direction and releasing the button after at least 3 seconds. The moment you release the button CaveSniper will "beep" and the number of beeps indicates how accurate and stable your measurement was. A single beep indicates the error larger than 0.5%, 2 beeps = 0.25-0.5% error, and 3 beeps indicate the error lower than 0.25%. To save your measurement into the memory, press the button three times to access the "Save point" screen and then hold it for two seconds. While this may sound complicated, after a few minutes you will get used to it and will make the measurements quickly.
To achieve best results, always try to keep the CaveSniper as far away from Leica as possible, as the Leica distancemeter has magnetic elements inside. The same applies to batteries, traditional magnetic compasses, metal hiking gear and other metal equipment, mobiles, etc.
Each CaveSniper is individually calibrated and provides tilt accuracy of appr. ±1 degree and compass accuracy of ±1.5 with the tilt in the ±60 degrees range. When the inclination is higher, the error margin increases slightly.
The resolution of both is greater than 0.1 degree. The accuracy of the distance meter is within ±1.5mm according to the manufacturer, with the range of up to 200m. In practice, a there and back measurement or closed loops have an error lower than 0.5%.
To verify the accuracy of the system outside the cave, make sure you do the tests away from buildings, railroads, metal fances, etc. Prior to testing CaveSniper inside caves, it was tested in a park, where copper nails hammered into trees were used as the pointers. As a reminder, a 1 degree azimuth error on a 100 meters route is equivalent to 1.745 meter error.
CaveSniper is powered from a Li-Jon 3.6V 950mAh rechargeable battery. It can be charged any time without the memory effect. Included in the package is a 4 AA battery external charger which can be used to juice up the device while in the cave. To fully charge CaveSniper you will need appr. 3 hours. If the LCD screen flickers during the use, it means the battery is almost empty and needs to be recharged. If you are not going to use CaveSniper for a longer period of time, it is recommended you sotre it with the battery appr. 50% full. In real-life conditions, a single charge was sufficient for the entire trip to Albania where more then ten caves were explored and carted.
To enter the service mode, press and hold the button while turning the device on. After 10 plus seconds, LCD will show "Statistics". The following data and functions can be accessed in the service mode:
Statistics: Route length Denivelation Start to End - distance and azimuth of the last point in relation to the first one. Max to Start - distance and azimuth of the point most away from the first one . Half to Start - distance and azimuth of the middle point in relation to the the first one (useful when measuting a route "there and back") Show points. A quick press will take you to the next point. Delete the last point Delete all points Sensors. Used for calibration only Voltage. Used in servicing only
Start to End - distance and azimuth of the last point in relation to the first one.
Max to Start - distance and azimuth of the point most away from the first one .
Half to Start - distance and azimuth of the middle point in relation to the the first one (useful when measuting a route "there and back")
Show points. A quick press will take you to the next point.
Delete the last point
Delete all points
Sensors. Used for calibration only
Voltage. Used in servicing only
When in the service mode, CaveSniper can be found by a PC or PocketPC for downloading data.
The CaveEplorer software can be used to import data from CaveSniper and save it to the following file formats: txt, dat (Compass), plt (OziExplorer), Kml(maps.google.com) and DXF, as well as to preview the route in three views, as well as in the extended side plan. It can also read txt and dat files and display simultaneously data from different files. This enables one to open parts of the route at the same time and watch the route develop as the measurements progress.
CaveExplorer can also be used on PC.
Once installed, turn the CaveSniper in the service mode (press and hold the measurement button while turning the device on), pairing it as a Bluetooth device (PIN 0000) and appointing a COM port to it. You can select a required language version as well as units (meters or feet). The language files are in XML format which makes them easy to edit to make anew one.
File - Open
You can open both txt and dat files
File - Add
This is used to simultaneously display more than one data set. Both files should have at least one common point (with the same name) or both should be txt files with the starting GPS location in it.
If you load two files with GPS location but without a common point, they will be displayed in actual real relation to each other.
File - Save
Saves data to file. You can save to one of five formats:
Txt – a text file. It can be edited with any text editor where you can e.g. edit a point.
Dat – (Compass) When saving to dat, all new format LRUDs (with azimuth, length and tilt) are automatically recalculated to standard LRUDs (left, right, up or down);
Plt – OziExplorer route format.
Kml – maps.google.com format
Dxf – a popular CAD format, full 3D form with additional measurements
To export to plt or kml, your starting point needs GPS co-ordinates. To get it:
File - Prefix.
Adds or deletes a letter prefix for all measurements. CaveSniper numbers your points with digits, to make sure you will be able to tell your routes apart, it is
recommended you use a prefix for each which you will recognize.
File - GPS position.
CaveExplorer works in WGS84.
Once you click File - GPS position, you can add the required co-ordinates in one of three ways:
- manually by typing in the co-ordinates in the degrees-minutes-seconds format
- by loading a previously saved GPS co-ordinates from file
- by inserting present GPS co-ordinates from a GPS receiver
Sniper - Find
Searches the ports looking for CaveSniper. Make sure the CaveSniper is in the service mode, and that it is paired with the PocketPC and have a port assigned to it. Make sure Bluetooth is on as well. The moment the software finds CaveSniper, you will see SniperComX in the Menu.
Sniper - Data Import
This is used to download data from CaveSniper. You will hear beeping during data transfer.
To view your cave in OziExplorer, save your route to plt with a GPS position and then move the file to \OziEplorer\Data. Open OziExplorer. Click File - TrackLog - LoadTrackFile. The route will display on the map (provided the correct map is loaded).
You can also view your route on http://maps.google.com/.
Save your data to KML.
Sign into your Google account.
Click MyMaps, Create new map.
Select your KML file and click Send to server.
The map should auto-focus to your route.
You will see the main and side routes, without the LRUDs.
GPS in practise
Access the cave entrance. Turn your PocketPC on and start the program. Click File - Import from GPS. Wait till correct co-ordinates are displayed. Save to File the co-ordinate and now you can turn your PocketPC off. Measure the cave with CaveSniper (see details above). Once done, turn the CaveSniper in the service mode, turn the PocketPC back on, turn Bluetooth on and start the software. Next click Sniper - Find, and then Data Import. Once your measurements show on the display in the txt format you can add a prefix for future reference. Click File - GPS, Load from File and select the previously saved file with the GPS location. Click OK. Go to File - Save and save your data along with the GPS starting position in a new file.
Now you have a single file with all the measurement as well as the GPS starting location.