A 577Kb PDF of this article as it appeared in the magazine—complete with images—is available by clicking HERE
For anyone out there that is still using the HP48 for data collection, this TDS combination allows for a very smooth transition to the latest in technology. Or, if you would rather pair the Ranger up with your existing total station, you can easily switch from one total station to another, or switch the Ranger from crew to crew as needed; simply select the instrument from a user-defined list of equipment.
For our evaluation, Tripod Data Systems (TDS) provided us with a complete package: the Ranger 500X data collector (in reality, a minicomputer), Survey Pro software and the new Nikon NPL-362 electronic total station for instrumentation. Ray Kerwin, the Regional TDS representative spent about a half day with our field crew and before he left us, we had gained the confidence to set our trusty HP48 aside and use the Ranger every day. We actually completed a job in the field with our first experience with the Ranger. Our field crew was able to become proficient with the equipment within a few days of use.
The TDS Ranger appears to be as "rugged" as their brochures proclaim it to be, although we did not attempt a 4-foot drop test, nor immerse it in water as advertised. We did however use it in the typical Upstate New York late fall/early winter weather (sun, rain, and snow with temps ranging from mid 70’s to low teens). We saw no change in operations, other than a slight reduction in battery life in the cold weather operation.
We were provided with two long-life battery modules. The TDS sales literature claims that the batteries will last up to 30 hours of use, dependent on the usual combination of temperature and various power-consuming functions. We did attempt to put the "long-life" to the test. Although we did not keep exact records as to how many hours and minutes we used the battery module before we had to exchange it for a fresh one, we were very happy with the amount of time we were getting out of a battery before receiving a notification of "low battery".
Changing the battery is a relatively simple operation and can even be accomplished smoothly while wearing gloves in cold weather. The stylus that comes with the Ranger doubles as a screwdriver to remove and install the battery module. There are a couple of things that are recommended by TDS that we agree with completely: purchase a spare battery module, and have it with you ready to change out. Thirty hours of useful battery life would seem like enough time to accomplish most any job. But, knowing it will last up to 30 hours creates somewhat of a false sense of security, which leads to the crew not putting the battery on charge each day. Doing several small to medium sized jobs over a period of several days, we found that we would not need to change or even charge batteries. One step that we found to be much different with changing this particular battery module compared to other data collectors is that you are supposed to power the unit on and leave it on while changing the battery module. We also found that if we didn’t power down the unit after changing the battery module, the battery indicator remained the same as for the battery that was just removed from the unit (which might make it appear that the battery just put in is also low on charge). A complete recharge takes only about 4.5 hours.
The Ranger comes with a pre-installed backup utility program called Sprite Backup. Initially I thought the Sprite backup was to be used regularly throughout the day to insure that no data Support on this issue and were told that was lost. This is not the case. The Sprite backup routine should be used any time new software is installed to the unit or when using non-TDS programs that store data to the RAM memory. This is to insure that you can restore the software if a hard reset should occur. Survey Pro is installed to the internal storage of the Ranger so the software cannot be lost. All the data that Survey Pro stores is also written to the internal storage as soon as it is computed. Even with a complete loss of power, all the data that Survey Pro stored will be retained. This is a great feature and is similar to the old RAM cards used on the HP48, except TDS tells me that the Ranger memory is more reliable, does not require battery power, and is built into the Ranger. You can use a CompactFlash memory card to copy data for an easy way of sharing data in the field if you want.
We made sure that we followed our normal daily routine of downloading our data collector before leaving for home each day. Unlike the HP48 for data collection, where one must manage the built-in memory carefully to make sure you don’t run out of memory while on the job, we found the 500X Ranger to have plenty of internal memory. Adding SD memory cards will also increase memory. During the several weeks of using the Ranger for various jobs, we didn’t have to worry about deleting projects from the data collector prior to working on another project.
The Ranger combined with the Nikon NPL-362 worked very well. One slight glitch we noticed is that with most data collectors and total stations, you can set the prism constant (i.e., -30 mm prism offset) in either the data collector or in the instrument, and the measured distance will be corrected for the offset. In our first trip to the field, we had set our prism constant in the instrument (and not in the Ranger), when we downloaded our data to the computer and reviewed the raw data file, we found that the printout noted the prism offset as zero (0), not the -30 mm that it should have been. This made all of our distances short by approximately 0.10 of a foot. We contacted TDS Technical the prism must be set in the Ranger in order to be recognized by the Survey Pro software. On the surface this sounds like an easy solution, however, you must dosome manipulation through the various screens in Survey Pro to arrive at the "Backsight Setup" screen, where you first set the instrument, click on the button for "Smart Targets," then set your prism constant.
A nice feature of the Ranger is that the "Smart Targets" button allows you to toggle back and forth between two targets of different prism offsets (if ever necessary) or between targets with different rod heights when shooting topography. You also switch back and forth to the "reflectorless measurement" mode through the use of the "Smart Target" button. We made the change as was suggested by Tech Support and the next raw data file read correctly for the prism offset.
Another feature that we found worked very well with the Ranger and the NPL362 combination was the "Repetition Shots" mode to turn sets of angles. Using this mode, we were consistently able to obtain traverse closures of greater than 1:50,000 and some as high as 1:150,000.
With the Ranger and Survey Pro software one can import a base map such as a topo quad sheet, an aerial photograph, a GIS data base plot, or even a boundary survey or deed plot that has been computed prior to going to the field and be able to orient your field work to the map while in the field. This should be very helpful in finding your way around a site whether on a boundary survey or on a construction site (where you can have something like a parking lot or a road alignment underlying your current field work). However, it does not appear at this time that we can make the base mapping and the current fieldwork map interact with each other.
With its Windows Mobile operating system and color screen, many add-on programs can be downloaded and installed on the Ranger such as Excel, Word, wireless, Bluetooth, and web connection features. Faithful TDS users will be happy to hear that the majority
of the COGO functions are identical to those used for years by TDS in the HP48. This allowed for a very smooth transition from the 48 to the Ranger. We didn’t really use the office software during this test drive other than using Survey Link (which we already use with the HP48) to upload and download coordinate files and raw data files (we are currently using other software for our data processing, computations and drafting in our office, and are at this time not quite ready to change everything). TDS does offer a newer file transfer and conversion package called ForeSight DXM. It uses the native files that Survey Pro produces on the Ranger and supports fast USB transfers. ForeSight DXM is designed to make it easy for Surveyors like me to integrate Survey Pro data into the existing CAD software that I have according to TDS. A notable feature is Survey Pro can take an ASCII (text) coordinate file and import it into the current job. This made it easy for us to get data out of our CAD software and into Survey Pro.
The Nikon NPL-362 also has an onboard data collection system available that we did not use or evaluate at this time. We found the optics to be very satisfactory. The focus knobs for both short and long distances worked well, even while wearing gloves. The built in EDM also worked very well. The battery pack is made to give you more than a "full day’s work". It is made to last up to 16 hours before needing a recharge. The sales brochure states, "with one measurement every 30 seconds, battery life extends up to 27 hours." We did keep a spare battery charged and ready, but found that the batteries lasted better than most. With a single prism, you can measure up to 16,400 feet.
The only shortcomings were that it did not seem to be able to "burn through" brush the way some other total station instruments can. We found that we needed a fairly clear line of sight even for the shorter distances. The literature also states that when measuring distances shorter than 30 feet, you must tilt the prism slightly to reduce the signal strength coming back into the EDM. This could be a potential problem for someone who doesn’t read manuals before operating new equipment. Also, because the optical plummet is contained in the body of the instrument instead of in the tribrach of the instrument, it does not lend well to the procedure of "leap-frogging" used often in traverses. The ability to rotate an instrument containing an optical plummet in the alidade allows the user to confirm the OP is in adjustment. This is achieved by looking through the OP as the instrument is rotated. If the OP is in adjustment, the OP’s centering circles remain centered on the point. If the centering circles meander about the point, the optical plummet is out of adjustment. Having the optical plummet in the alidade enables the user to confirm the optical plummet is in adjustment and hence that the instrument itself is centered directly over the point.
Overall this TDS package performed very well for us in all kinds of weather. It allows for a seamless transition into the latest technology available in data collection and radial stakeout. We experienced a very short learning curve with both the Ranger and with the NPL-362 total station. Our productivity increased in the area of 50 percent by the time we were on our second job, and increased by at least another 50 percent over the period of a couple of weeks. The Ranger 500X has all the horsepower (520 MHz, 128 MB SDRAM 20MB reserved, and 512 MB data storage (On-board Flash 26 MB reserved) that the smaller firm would ever need, and if cost is an issue purchasing the Ranger 300X now can save you some money, while still allowing for adding memory through the use of adding more data storage later on by using the new Secure Digital (SD) slot. You can also use the Ranger’s two Compact Flash (CF) slots to add GPS, GPRS, digital cameras, bar code scanners and other CF devices.
Tom Merrill has been licensed in New York State since 1984. Prior to launching his own business in Watkins Glen, NY, he was Survey Department Head for Greenhorne & O’Mara in Germantown, Maryland. Merrill was featured in the ProFile section of the charter issue of TAS (Jan/Feb 2004).
A 577Kb PDF of this article as it appeared in the magazine—complete with images—is available by clicking HERE