The current and interesting thread [msg=243606]Wild T12[/msg] reminds me of a time when i mistakenly referred to laser range-finders as "hand-held total stations". My reasoning went something like this:
- they measure horizontal angles (yes, i know magnetic bearings are not the same as turned angles)
- they measure vertical angles
- they measure distances
- they do not require a tripod
My problems with "laser range-finders" are
- there's no implication about what, if any, angles are measured (and aren't there some that do not measure bearings/inclinations?)
- "laser" is rather specific -- what if a different distance measuring technology is used? (I'm not saying that will happen, but EDM has used many different types of signal.)
So my questions are
- 1. What might be a better term than "laser range-finders"?
- 2. What are the modern-day equivalents, if any, to the Wild T12 (ie, very light-weight theodolites)?
- 3. What are the very light-weight total stations, if any?
- 3. I realize that laser range-finders and GPS devices have perhaps rendered (2) and (3) unnecessary, but what happens in, say, rugged, remote areas where GPS is impossible, laser range-finders are inadequate, and common total stations are too burdensome?
Feel free to answer any number of the above.
Horizontal and vertical angles as well as distances can be computed from coordinates observed with Back-Pack Inertial Guidance System (INS) equipment. Primarily utilized by geophysical prospecting firms, they work quite well in rugged terrain obscured by trees. Note that accuracy deteriorates with time+distance.
NOT hand-held, but worn with a back pack. Pricey (~$250K).
Hmm, yes, i'd forgotten about INS. I think the price would put off anyone but the wealthy exploration surveyors.
Martin,
Actually, the modern hand-held laser-rangerfinder can already be setup to be used as a total station either with or without relying on the magnetic compass for horizontal angles. (The built-in vertical inclinometers are already stable and accurate enough for most surveying needs since the gravity vector is pretty constant across the globe).
Leica (subsequently spun-off/divested into Vectronix) developed the Leica Viper/ Vector laser rangefinder-binocular for use with forward observing units for the US Military in the 1990's.
Weight is about 4 lbs; rangefinding distance with the Vector21 is up to 12km /12,000 yards -(that's over 7 miles! ) reflectorless with a resolution of 1meter/ 1 yard; (resolution to .1meter (10cm), or about 4inches- is available up to 4km) output can be via bluetooth or serial port to a smartphone, PDA or dedicated targeting system. Horizontal compass angle to nearest .5 degree; vertical inclination to .1degree.
Granted, at 12km you'll need a target the size of a building/ water tower/ tank/jeep to return enough energy for reflectorless use... but a decent 7-prism target should also suffice at 7 miles.
If one wanted, with the addition of a tripod-based independent angular measurement system (known as a goniometer) you could get it to 10" -basically just a fixed circular encoder that can remain stationary while the binocular is rotated, allowing horizontal measurement without concerns regarding the internal magnetic compass-based unit.
They can also be integrated with a GPS and/or gyro system, to provide the GPS coordinates of the targeted object- if you know where the laser rangefinder is, then given a distance and angular deflection to the target it's possible to compute the coordinates of the target. These are known as Target Acquisition Systems.
Images below (Top-Bottom) are with the Goniometer, GPS, and Gyro systems, respectively:
Vectronix handheld laser rangefinder product line catalog is here:
Vectronix hand-held laser rangefinder product line
Various military units find these quite useful for battlefield observation, targeting, and close-in target acquisition. They are also commercially available with long-range shooting competition (or snipers) to use with their weapons; a company called HORUS VISION has integrated them with a handheld computer, a KESTREL environmental sensor, and programmed software (ATRAG Ballistics) to provide corrective targeting data for firearms (up through the .50cal Barrett rifle)
> Vectronix handheld laser rangefinder product line
Very interesting -- thanks! Vectronix is targeting ('scuse the pun) the military market. Does anyone know how they compare (price, accuracy, etc) with light-weight survey-oriented equipment?
Carlson was working on a small total station that would go on a prism pole and bi pod . I think there was a video on the net showing it . But appears it may have been vaporware . Seemed like a good idea in the woods .
