Leica rigid tripod. Stainless steel target poles supported by Leica telescopic bi-poles (2). Shortened stainless steel target pole for the SEAFRAME sensor BM connection. Leica cast iron change plates (2). Kestral 4000 pocket weather tracker Method The EDM height traversing technique was employed for the Betio Island tide gauge “Leap-Frog” levelling survey. This technique involves setting up a total station (TCA1800L) midway between two target/reflectors (on reflector rods with struts). The targets remain at a particular change point for the back-sight and fore-sight observations. The instrument measures slope distances (±1mm) and vertical angle (1”) to derive height differences (between the instrument’s trunnion axis and the reflectors). In support of the slope distance observations, the ambient temperature, pressure and humidity are recorded (Kestral 4000 pocket weather tracker) and input into the instrument to apply the first velocity correction to the observed distances (Rüeger & Brunner, 1982). Four rounds of observations are taken to the back-sight and fore-sight targets from each instrument setup. All levelling runs started and finished with the same reflector and reflector rod, i.e. an even number of setups when the two reflector rod configuration was used. This eliminates any reflector rod zero error. This technique can also be performed using a single set-up / single rod configuration which is particularly useful when levelling between bench marks which are close together e.g. between the CGNSS RMs. Reduction of the digital data was computed by the Geoscience Australia levelling program This program computes the height difference between the two reflectors. “leveling1.exe”. Survey Assistance from Iabeta, Acting Chief Surveyor in absence, and his staff; from the Ministry of ’s Lands was appreciated, they provided great support throughout the survey, including assistance in obtaining customs clearances for the surveying equipment. This is a lengthy process and seems to becoming more time consuming throughout most countries in the Pacific. The from the Kiribati Weather Office also provided great assistance during the 2012 visit. Issues No issues of any significance were encountered during the 2012 visit.
Leica rigid tripod. Stainless steel target poles supported by Leica telescopic bi-poles (2). Shortened stainless steel target pole for the SEAFRAME sensor BM connection. Leica cast iron change plates (2). Kestral 4000 pocket weather tracker Method The “Leap-Frog” EDM height traversing technique was employed for the Betio Island tide gauge levelling survey. This technique involves setting up a total station (TCA1800L) midway between two target/reflectors (on reflector rods with struts). The targets remain at a particular change point for the back-sight and fore-sight observations. The instrument measures slope distances (±1mm) and vertical angle (1”) to derive height differences (between the instrument’s trunnion axis and the reflectors). In support of the slope distance observations, the ambient temperature, pressure and humidity are recorded (Kestral 4000 pocket weather tracker) and input into the instrument to apply the first velocity correction to the observed distances (Rüeger & Brunner, 1982). Four rounds of observations are taken to the back-sight and fore-sight targets from each instrument setup. All levelling runs started and finished with the same reflector and reflector rod, i.e. an even number of setups when the two reflector rod configuration was used. This eliminates any reflector rod zero error. This technique can also be performed using a single set-up / single rod configuration which is particularly useful when levelling between bench marks which are close together e.g. between the CGNSS RMs. Reduction of the digital data was computed by the Geoscience Australia levelling program “leveling1.exe”. This program computes the height difference between the two reflectors. Survey Assistance from Iabeta, Acting Chief Surveyor in ’s absence, and his staff; from the Ministry of Lands was appreciated, they provided great support throughout the survey, including assistance in obtaining customs clearances for the surveying equipment. This is a lengthy process and seems to becoming more time consuming throughout most countries in the Pacific. The from the Kiribati Weather Office also provided great assistance during the 2012 visit. Issues No issues of any significance were encountered during the 2012 visit.