The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part B4. Beijing 2008 
3.2.2 Case 2: Real-Time Kinematic Positioning Highway 
Mapping 
Various RTK survey tests were executed at different distances 
from the permanent stations aiming at testing the substructure 
and the accuracy quality of the network. The equipment used 
was the Leica Geosystems SR520 and GRX1230 receivers. The 
initialization test (KIS) was performed using the GRX1230 
geodetic GPS receiver in the broader area of the Paralimni town. 
The campaign was scheduled in order to have the maximum 
GPS visibility. The recording interval for the kinematic chain 
was set equal to 2 sec. The measured points were processed 
from the two permanent stations of Lamaca and CavoGreko 
(southeastern of Cyprus) in order to test the method 
effectiveness on various baseline distances. Specifically, the 
test distances varied from about 1 to 21 Km. 
For every occupied point, we calculated the distance between 
the point obtained from DGPS and the one from kinematic post 
processing (KIS-PP) (Pala et.al., 2003, Xinhua, WU. et.al., 
2004). In addition, some points of the kinematic also were 
measured with RTK in order to simultaneously evaluate the 
accuracy of this method against the other techniques. It is 
critical to report that several problems came up, mainly due to 
obstacles to the radio-modem signal communication. Therefore, 
a GPRS connection is preferable (Gao Y., 2002). Also a post 
processed single point position (SPP) based on C/A code data 
was estimated and evaluated accordingly. A part of the 
kinematic chain trajectory starting from the broader area of the 
Paralimni with direction to Lamaca is shown on the following 
Figure 2. 
Figure 2. The GPS Kinematic trajectory 
The comparison between obtained positions from phase (fixed) 
solutions, using different permanent station data, shows an 
agreement at the order of few cm, value which meets the 
manufacture’s accuracy specification. 
Also, the results confirmed the expected sub-meter precision for 
the code differential mode. Such accuracy data are quite useful 
for fleet management. In addition, it is proved that DGPS, due 
to the high rate of collecting the necessary information, is 
probably the best mobile method for map generation (or update) 
for scales 1:5000 and smaller. There is no need for initialization, 
cycle slip fixing and ambiguity resolution and of course the 
installation cost is highly reduced. 
solution, for selected points of the kinematic trajectory. As it is 
known the height dimension is the mainly affected one so this 
quantity was selected to represent the worse case. It is clearly 
shown that the differences are lower than 5 cm except for a few 
points where the re-initialization was necessary after loss of 
signal lock (lower than 4 satellites tracking) (Hofmann- 
Wellenhof et.al., 1997). 
Height differences between Kinematic - RTK 
Figure 3. Height differences between Kinematic and RTK 
solutions 
In addition to the above test, another survey was concurrently 
contacted using only low-cost handheld GPS receivers (at cost 
of 300 €), aiming at accuracies at the order of 1 m. The 
achieved DGPS results confirmed that accuracies of better than 
1 m are achievable under regular survey conditions (Fig. 4). 
DGPS Positioning Error 
(4.0—5.0) m 
(5.0—6.0) m 
(3.0—4.0) m 0.2% 
0.2% 
1% 
(2.5-3.0) 
6.0 m kqi novio 
{2.0—2.5) \ / 
3% 
(1.5—2.0) m 5% 
(0.0—0.5) m 
4!% 
5% 
(1.0-1.5) m S' 
16% L ^|H 
(0.5—1.0) m 
27% 
Figure 4. Accuracies of the DGPS solution. In 68% of the cases 
the accuracy is better that 1 m. 
3.2.3 Case 3: Parcel identification and measurement with 
low-cost GPS receivers 
This application aims at the evaluation of the performance of 
the PSI network in the determination and improvement of the 
position of parcel boundaries for the update of the national 
vineyard cadastral. With the use of data from low cost portable 
GPS receivers as also from the referenced stations of the 
Cyprus PSI network, the technique of relative kinematic 
positional determination is applied using C/A code data. The 
parcels chosen f are shown in Figure 5. The closest permanent 
PCI network station is used as a referenced receiver. 
The following diagram (Figure 3.) shows the height differences 
between the post-processed kinematic solution and the RTK 
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