Test Dataset 1 - Residual Stacking

Mean residual maps - Comparison between different periods

Residuals have been stacked over three different periods in 2000. After the first period, there have been some changes in antenna with respect to the second and third, or main, period. This allows us to investigate the effect of antenna changes on the one hand, and sensitivity and repeatability of the residual stacking on the other hand. The three main periods are

1. Day 110-117 2000 (8 days)
   The Dutch stations Delft, Eijsden and Terschelling used different antenna and receivers compared to the other two periods.
2. Day 200-207 2000 (8 days)
   Actually, the antenna and receiver in Delft has been changed during the middle (day 205) of the 2nd period. Therefore, results for Delft are analysed for 5 days directly before the change (day 199-204) and 5 days directly after the change (day 206-211).
3. Day 297-311 2000 (15 days). This is the main period.

The mean residual, in [mm], is plotted in a polar plot of elevation and azimuth, using approximately 1 x 1 degree bins, for the three different periods

Period 1 day 110-117 2000 (8 days)	Period 2 day 200-207 2000 (8 days)	Period 3 (main period) day 297-311 2000 (15 days)
Delft (DELF) AOA SNR-12 RM AOAD/M_T DUTD	Delft (DELF) AOA SNR-12 RM AOAD/M_T DUTD	In Delft the receiver and antenna where changed during the middle of the 2nd period. In the middle column (to the left) is plotted day 199-204. In the middle column on the next row is plotted day 206-211.
	Delft (DELF) TRIMBLE 4700 TRM29659.00 UNAV	Delft (DELF) TRIMBLE 4700 TRM29659.00 UNAV
Eijsden (EIJS) AOA SNR-12 RM AOAD/M_T DUTD	Eijsden (EIJS) TRIMBLE 4700 TRM29659.00 UNAV	Eijsden (EIJS) TRIMBLE 4700 TRM29659.00 UNAV
Terschelling (TERS) AOA SNR-12 RM AOAD/M_T DUTD	Terschelling (TERS) TRIMBLE 4700 TRM29659.00 UNAV	Terschelling (TERS) TRIMBLE 4700 TRM29659.00 UNAV
Westerbork IGS (WSRT) AOA SNR-12 ACT AOAD/M_T DUTD	Westerbork IGS (WSRT) AOA SNR-12 ACT AOAD/M_T DUTD	Westerbork IGS (WSRT) AOA SNR-12 ACT AOAD/M_T DUTD
Westerbork IGS and AGRS use the same antenna, but are different receivers.	Westerbork AGRS (WSRA) TRIMBLE 4700 AOAD/M_T DUTD	Westerbork AGRS (WSRA) TRIMBLE 4700 AOAD/M_T DUTD
Kootwijk IGS (KOSG) ROGUE SNR-12 RM AOAD/M_B DUTD	Kootwijk IGS (KOSG) ROGUE SNR-12 RM AOAD/M_B DUTD	Kootwijk IGS (KOSG) ROGUE SNR-12 RM AOAD/M_B DUTD
Kootwijk IGS and AGRS use the same antenna, but are different receivers.	Kootwijk AGRS (KOSA) TRIMBLE 4700 AOAD/M_B DUTD	Kootwijk AGRS (KOSA) TRIMBLE 4700 AOAD/M_B DUTD

The following can be concluded from these results

• Maps for the same station are very similar from one period to another, as long as the same antenna is used
• Even when antenna's have been changed, the same high periodic variations can be observed, which is an indication that by changing the antenna mainly the low periodic elevation dependency is affected, see also the elevation dependency plots
• The variation between stations are larger than variation within a station due to antenna changes, which is a sure indication that the maps are mainly influenced by the near field environment (multipath), and which corresponds to the observation that the magnitude of elevation dependent variations are somewhat lower, see also the elevation dependency plots
• Kootwijk and Westerbork use two different receivers, connected to the same antenna by means of antenna slitters. The results are very identical, indication that the elevation dependent and azimuth dependent effect originate in the antenna, radome and/or near field environment (multipath). Differences in receiver performance can be observed in the plots of empiral and formal standard deviation