Wednesday, 12 October 2016

Lesson Note On How to Carry Out Surveying from a Known Point With Leica Total Station

How to Carry Out Surveying from a Known Point With 

Leica Total Station

Image result for LEICA TOTAL STATION setupImage result for LEICA TOTAL STATION setup
When the total station is set up and level over the known point it will require another known point to help calculate the coordinate reference system that the unknown measurements will be measured with. That is to say that the total station will be able to know the angular relation between the easting, northing and elevation of itself and the Easting northing and elevation of the second known point (often referred to as the back sight). Then all of the angles and distances measurements calculated and computed with the laser will be translated into the same east, northing and elevation coordinate space as well.
Image result for LEICA TOTAL STATION setupImage result for LEICA TOTAL STATION setup

Create a Measure Job File

From the main menu, select Meas job management by pressing the number 1 on the keypad (from the Main Menu).  The measure job created will be the file that your measured points in your survey will be recorded.
Next press F2 to open the Create new job menu.
Leave all settings at default and enter a new job name by using the letters on the keypad.
The F6 key (NUM) will switch the key pad between numbers and letters.  Note it may take some practice to get used to this switching back and forth.
After the new file name has been entered press F1 to continue.
Next ensure that the job file that you have just created is highlighted and select CONT again by selecting F1 from the keypad.

Create a Data Job File


The data job is where the known or fixed points are stored (the Data job file can be the same as the measure job file but often it is good survey practise to keep these two files separate).
Steps followed for creating a data job file are very similar to those mentioned above for creating a measure job.
From the main menu, select data job management by pressing the number 2 on the keypad.
Next press F2 to open the Create new job menu (and provide a file name like you did above) or select an existing data job file if one exists. Then press F1 to continue.
If it is a new data job file then you will need to input values for the known points.
Select the FNC key from the bottom grey keypad.
Select menu item 5 Data view and Edit
On the next screen select Input from the function key options by pressing the F3 key.
Enter the name of the point id of the known point you wish to create.
Enter the known Easting, Northing and Elevation values for this point.
Press REC to accept the value of the point id
Repeat the steps to enter all the known points that you wish to use in your survey and then use the ESC key until you reach the main menu again.

Select your Codelist

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From the main menu, select codelist management by pressing the number 3 on the keypad.
Select the name of the code list you created earlier with the Leica Survey Office software and uploaded to the memory card. Then press F1 to continue.

Record Backsight Locations

From the Main Menu select Setup from the bottom of the screen by pressing F5.
In the Job settings menu you should see the name of your measure job, data job, and code list. If either looks incorrect than go back and select them again using the instructions from the start of this manual.
Select QSET (quickset) from the bottom of the menu using F4.
For the Station Id enter the point id of the known point for the surveying monument that you have the total station set up upon.
Next enter the Backs. Id to select the backsight point id
Enter the instrument height of the total station that you recorded previously in the initial setup.
Enter the base height of the reflector poles used to collect the various points during the survey.  The number to enter here will be the value found above the grasp of the reflector pole. A height of 2 meters is common height for reflector poles in most surveys but sometimes there is a need to use different height values.
Aim the total station instrument towards the survey prism with the and press F2 on the key pad which selects DIST. Ensure that the range pole is vertical and plumb by centering the bubble on the pole. This will allow the Total Station to compute the delta of what you told it where it was and where it is based on the reading of shooting the pole.
Take note of the delta horizontal distance on the screen. Anything under 2cm is considered an acceptable value. Once accuracy under 2cm is achieved hit CONT by pressing F4 on the key pad.  The unit will now know spatially where it is located and surveying of the unknown points can commence.
The screen should now have an option MEAS appear in the lower right corner of the screen, this is an indication that you can now shoot to any unknown point with the reflector. 
 Press the F6 function key to enter into the measure and Record menu. Here you can point and aim at the reflector, enter the point Id value and then press the F3 function key to record the coordinate values of that point. The total station will increment the point ids taken automatically, or you can change the values manually each time.
Tip: Remember to adjust the height of reflector on this screen if the height of the reflector unit is adjusted during the survey.
To finishing surveying simply press ESC until the screen is back to the main menu. Press both the ON button and the left arrow button at the same time to shut down the unit.
Tip: How to adjust the view of the Total Station
Use the “sight” on the total station to roughly point the Total station at the reflector.  Then use the knobs to fine tune the view at the reflector target.  Use the focus on the lens to ensure a clear and focused view of the target and that the cross hairs are centered on the center of the target. 

HOW TO SURVEYING FROM AN UNKNOWN POINT WITH LEICA TOTAL STATION

SURVEYING FROM AN UNKNOWN POINT
 WITH 
LEICA TOTAL STATION
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The total station can be used to survey in locations where you do not know the value of the point upon witch it is setup upon, this is known as Free Station Surveying. This survey technique is often used when you have two points with known established coordinate values but are not in an ideal place to perform your survey from, or at times where you wish to progress further into an unknown survey region.
A good example for using this technique would be if you needed to measure points under a dense forest canopy where your GPS could not provide high precision point values. In a case like this you would use the GPS unit to establish known values around the perimeter of the tree stands and then use them as back-sights so that you can setup your total station in under the forest canopy.
You would then be able to establish the value of this unknown point and then continue collecting other unknown points as well.  Accurate results from this style of surveying rely on careful planning and the use of good geometry when setting up your known point.
Set up is similar in many ways to the set up technique explained earlier when surveying with the total station setup over a known station. Therefore we will assume that you can follow the steps outlined above in earlier sections for instructions on setting up the total station, leveling the unit and measuring the HI.
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– Create the measure job, data job and select codelist as outlined previously (all the steps are the same).
– Once the above steps have been taken return back to the main menu and press the PROG key from the bottom row of the key pad.
– Next select Free Station from the program Selection menu by pressing 1 on the key pad.
The station ID is a uniquely identified for the point that you are occupying.  It is good practice to use the point id values of the two known points that you will be measuring as this identifier.  Something like pt1 or pt2 can also be used.
– Enter the instrument height (HI) of the total station.  Press CONT by using the F1 key.
Now you will be on the Target Point screen.
– Enter the ID of the first known point you wish to use. Enter height of reflector pole with the prism above the unknown point. Aim the total station towards the reflector.
Then shoot the laser at the reflector with SEARCH by hitting the F1 key.
On the next screen press F2 to use the DIST function. Keep pressing the using the DIST function until the number you see is resolved to within 5mm of the last two DIST measurements. After you are satisfied with the value that was resolved from the measurement process then Press F4 CONT.
Repeat these steps for the second known point.
Once these two points have been shot use the F6 button to access the CALC function. This will do the math for the total station to figure out where it is set up upon. The total station will know spatially where it is located so that it can measure and calculate more unknown points within the survey area.

Note: You may result with an error screen telling you the error calculation is too large. If this occurs you must try to resolve this by shooting to the two known points again to obtain better, more accurate data.  What has occurred is that the place where you told the Total station that the two points are not matching up wit the math it does to confirm that and establish it own position.
If everything is fine you will arrive at a screen that will give you and option on the bottom left screen above the F1 key SET. Press F1 to establish the Total Stations position. This brings you back to the main menu.
 You can now use the MEAS function to begin your survey as per the instruction in setting up over a known point explained above.

Thursday, 6 October 2016

Federal Civil Service Commission Announces Vacancies in The Federal Civil Service.

PUBLIC NOTICE
PUBLIC NOTICERAL CIVIL SERVICE COMMISSION RECRUITMENT PORTAL-(vacancy.fedcivilservice.gov.ng) IS OPENED BETWEEN THE 19TH OF SEPTEMBER AND THE 31ST OF OCTOBER 2016-(SIX (6) WEEKS).
PLEASE NOTE FOR CLARIFICATION THAT THERE IS NOTHING LIKE ‘’ FIRST COME, FIRST SERVICED’’ ON FEDERAL CIVIL SERVICE COMMISSION RECRUITMENT PORTAL.
QUALIFIED APPLICANTS ARE ONLY REQUIRED TO SUBMIT APPLICATIONS ONLINE AT ANYTIME WITHIN THE SIX (6) WEEKS PORTAL OPENING PERIOD.
FEDERAL CIVIL SERVICE COMMISSION.

READ THIS INSTRUCTION BEFORE APPLYING

A GUIDE TO COMPLETING FEDERAL CIVIL SERVICE ONLINE COMPETENCE-BASED APPLICATION FORM

The internet is being used more for advertising jobs and accepting applications. It’s very important to learn how to apply online for job opportunities. Online application forms allow you to save time, postage, and paper. However, some can be a bit tricky to complete.

Filling out an Online Competence-Based Application form can be tough if you don’t have all the information you need and computer competency. The application completion and submission process is part of the candidate’s selection process.

This Online Competence-Based Application Form contains eighteen (18) sections, so be prepared with all your biographical data; schools & education certificates, employment history and others before clicking the "Apply" button. It may take on the average thirty (30) minutes to complete the form. Use the "Save Draft" button as often as possible while completing the form. You will be able to edit the form after submission by clicking the "My Portal" menu, before the application period closes.

BE CAREFUL OF SCAMS. NO LEGITIMATE EMPLOYER WILL ASK FOR PERSONAL INFORMATION SUCH AS CREDIT/DEBIT CARD NUMBERS OR BANKING INFORMATION.

Wednesday, 28 September 2016

Lesson Note On Step-by-Step RTK Setup Guide - Part B

RTK Setup Guide

The following is a concise step-by-step guide to setting up the Trimble equipment for RTK surveying. It does not cover the theory of operation; these instructions are much more useful after an introduction to the system.
Image result for TRIMBLE rtk gpsImage result for TRIMBLE rtk gpsImage result for TRIMBLE rtk gps
Rover setup - do this after the base station is running
1.     GPS receiver
1.     Place 2 charged camcorder batteries in the holders at the bottom of the rover backpack.
2.     Connect the battery cables to the batteries, and use the Velcro straps to secure the batteries and cables in place.
3.     Strap receiver into the backpack, upside down. Use the lower set of straps, which have 2 black foam pads underneath.
4.     Connect the battery cables to ports #2 & #3 on the GPS receiver.
5.     Thread the radio antenna cable through a top cable pass-through, and attach the antenna mount to a brass threaded mount on the backpack. (The radio cable is normally left in the backpack, so this step is normally skipped.)
6.     Connect the radio antenna cable to the GPS receiver.
7.     Attach the radio antenna, with the correct tip (0dB or 5dB).
8.     If not using the 2m range pole, attach the GPS antenna to the 3rd piece of the radio mast, and attach that to the other brass mount on the backpack.
9.     If using the 2m range pole, attach the antenna to a Quick-Connect shaft, and attach the quick-connect to the assembled range pole.
10. Thread the GPS antenna cable through the other top cable pass-through and coil neatly above the receiver. Do not kink the cable. Connect the 3-shell Lemo [large] to the GPS receiver, and the coaxial connector to the antenna.
11. Connect the data collector I/O cable to receiver port #1.
12. Thread the data collector I/O cable through the lower pass-through on the same side as the GPS antenna cable. Connect to the data collector.
13. Tie down loose cables in the pack, and zip it closed.
14. Put on and adjust the pack for a comfortable fit.
15. Turn on the data collector (and hence the GPS receiver).
16. Measure vertical height of the antenna; this is measured to the bottom of the antenna mount, and can be done with the Height Rod. Check that the measurement type is correct.
2.     Start the rover measurements
1.     Make sure that the correct Job is selected on the data collector. New Jobs may be defined in the Files mode.
2.     On the hand controller, choose Survey, and then choose the appropriate Survey Style; typically Trimble RTK or a custom style. New styles may be defined at this stage, or in the Survey Styles option in the Configuration mode. Be sure to choose the same style as for the base station.
3.     Choose Start survey.
4.     Choose Measure PointsContinuous Topo, etc.
5.     When measuring points (of any type), the Rover will attempt to initialize on-the-fly (OTF). This can only be done if 5 or more satellites are visible and tracked by both the rover and base station.
6.     When the radio link is locked, and the receiver has completed the OTF initialization, the status line on the data collector will have estimated uncertainty and "RTK Fixed" displayed. You can know begin measuring points.
7.     If less than 5 satellites are visible, it is possible to initialize on a known point. However, the data quality is liable to be poor due to the low number of satellites. It is often advisable to change locations or try the survey at a later date with more satellites.
8.     For all GPS surveying, try to keep the PDOP < 6.0 - the best yet seen was 1.7 (8 satellites in open terrain), and PDOP tends to average about 3.0 with 5 or more satellites.


Lesson Note On Step-By-Step To RTK Setup Guide - Part A

RTK Setup Guide

The following is a concise step-by-step guide to setting up the Trimble equipment for RTK surveying. It does not cover the theory of operation; these instructions are much more useful after an introduction to the system.
Image result for rtk gpsImage result for rtk gpsImage result for TRIMBLE rtk gps
Base Station Setup - do this first
1.     GPS Receiver
1.     Setup GPS antenna tripod and tribrach; insure that the optical plummet is aligned with the base station benchmark, and that the tribrach is level.
2.     Attach GPS satellite antenna ("GPS antenna") to the tribrach via the brass adapter. Attach GPS antenna cable (yellow 3-shell [large] Lemo to right-angle coaxial connector) to the antenna.
3.     Connect the base station battery (use the attached cable) to port #2 of the GPS receiver.
4.     Connect the GPS antenna cable to the receiver's antenna port (labelled, and the only port that fits).
5.     Connect the data collector I/O cable to receiver port #1; the cable is black, with 0-shell [small] Lemo connectors on each end. One end is straight, the other a right-angle. Connect the right angle connector to the receiver.
6.     Place the receiver inside the transport case (for weatherproofing). Be sure not the have any sharp bends in the cables, and do not clamp the lid on any cables.
7.     Connect the data collector to the other end of the data collector I/O cable connected to receiver port #1.
8.     Turn on the data collector and GPS receiver by pressing the green power button on the data collector.
9.     Measure the GPS antenna height using the Height Rod. Measure at 3 points (120 degrees apart). Always measure from the benchmark stamp to the bottom edge of the groundplane, inside a notch. Record the three measurements; if they are different by more than a few mm, check level and centering of the GPS antenna. Average the readings and enter the average into the data collector when prompted; either enter in meters, or type in the number followed by the unit (e.g. cm for centimeters). Check that the measurement type is set correctly.
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2.     Base radio
1.     Choose a location more than 10' from the GPS antenna. Do not choose a location near trees, cars, buildings, etc.
2.     Setup tripod with tribrach, levelling at the highest possible stable height.
3.     Attach the radio antenna cable to the tribrach with the brass adapter. If possible, use 2 pieces of the radio mast to increase the height of the radio antenna; save the 3rd piece for the Rover system, if not using the 2m rangepole.
4.     Attach the radio antenna, with tip (0dB or 5dB), to the radio antenna cable.
5.     Put the base radio near the radio antenna, preferably in a sheltered location. At the very least, place the cooling fan downhill without restricting airflow.
6.     Connect the radio antenna cable to the radio; there is only port that will work, and it is labelled.
7.     Connect the power cable to the radio; there is only one port that will work, and it is labelled. Be sure to align the red dot and mark before pushing with any force.
8.     Connect the donut lugs on the power cable to the battery; red to positive. 

DO NOT CONNECT WITH REVERSE POLARITY; the 10A fuse in the cable will blow, and it is possible to damage the radio.
9.     Connect the green ground cable (spade lug to alligator clip) to a real Earth ground. If no metal is readily available, use a piece of metal bar driven into the ground.
10. Turn on the radio; remove the removable faceplate, and use the black knob. This is also the volume control.
11. Select a channel that is not in use. Preferably avoid channels 15 and 16, as the FCC has an unusually large number of complaints on these channels. Make sure that the status light is green, indicating the use of Carrier Detect; changing carrier detect requires use of a PC and the COMMSET program.
12. Once a channel is selected, close the faceplate and note the channel number; this will be needed for the rover.
13. Connect the base radio data cable (30m flat yellow jacket, 1-shell Lemo [medium] to 0-shell Lemo) to the GPS receiver port #3.
3.     Start the base station measurements
1.     Make sure that the correct Job is selected on the data collector. New Jobs may be defined in the Files mode.
2.     On the hand controller, choose Survey, and then choose the appropriate Survey Style; typically Trimble RTK or a custom style. New styles may be defined at this stage, or in the Survey Stylesoption in the Configuration mode.
3.     Choose Start base station. Type in the benchmark name, and the position, if known. If no position is known, the Here softkey will use the current GPS position. This is not very accurate, and is not recommended for precision work.

4.     Press the measure softkey, and disconnect the data collector when instructed to do so. Do not turn off the base receiver. Check that the satellite LED (red) is blinking slowly on the GPS receiver, and the transmit light (labelled "TX") on the base radio blinks once per second. This indicates everything is working correctly.