mbuonanno
lvl.4
Italy
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patiam Posted at 4-13 08:41
To clarify what I think both @Straightarrow & @mbuonanno are saying, no matter what mode you use, the D-RTK 2 initially calculates the X,Y,Z of the antenna phase center (APC).
If in Mode 1, and you are entering a known coordinate into the UI for the benchmark over which you have placed the base, you must ADD the height of the APC on its pole to that of the benchmark Z on the ground before entering it.
Hi patiam,
We all agree that "no matter what mode you use, the D-RTK 2 initially calculates the X,Y,Z of the antenna phase center (APC)".
As far as I know, at present the D-RTK2 in Mode 1 calculates the APC coordinates using a Code-based pseudorange solution (single Point Positioning - SPP)(RTK differential is available in Mode 3 only). The system averages the solutions for about 50 seconds and then freezes the position on the calculated average.
e.g. (from a user_log .DAT file)
bestpos:0,0ms,type:0,lat:0.000000000,lon:0.000000000,hgt:0.000,std(0.000000,0.000000,0.000000)
bestpos:2082,133858200ms,type:16,lat:40.838071183,lon:14.364137186,hgt:193.776,std(1.469309,1.049694,2.386449)
bestpos:2082,133858400ms,type:16,lat:40.838057752,lon:14.364110893,hgt:198.016,std(2.146445,1.552083,3.531028)
bestpos:2082,133858600ms,type:16,lat:40.838057940,lon:14.364110973,hgt:197.990,std(2.146502,1.552072,3.530988)
bestpos:2082,133858800ms,type:16,lat:40.838056888,lon:14.364110778,hgt:197.986,std(2.109553,1.552364,3.531375)
bestpos:2082,133859000ms,type:16,lat:40.838057086,lon:14.364110868,hgt:197.997,std(2.109610,1.552353,3.531334)
...
bestpos:2082,133907600ms,type:16,lat:40.838053817,lon:14.364128558,hgt:196.076,std(1.658283,1.278527,2.777866)
bestpos:2082,133907800ms,type:16,lat:40.838053803,lon:14.364128663,hgt:196.058,std(1.652255,1.256276,2.755571)
bestpos:2082,133908000ms,type:16,lat:40.838053810,lon:14.364128752,hgt:196.040,std(1.650643,1.255451,2.749521)
bestpos:2082,133908200ms,type:16,lat:40.838053814,lon:14.364128844,hgt:196.024,std(1.650670,1.255441,2.749503)
... then after 50sec it calculate the average solution
bestpos:2082,133908400ms,type:1,lat:40.838053603,lon:14.364117239,hgt:197.287,std(0.000000,0.000000,0.000000)
bestpos:2082,133908600ms,type:1,lat:40.838053603,lon:14.364117239,hgt:197.287,std(0.000000,0.000000,0.000000)
bestpos:2082,133908800ms,type:1,lat:40.838053603,lon:14.364117239,hgt:197.287,std(0.000000,0.000000,0.000000)
bestpos:2082,133909000ms,type:1,lat:40.838053603,lon:14.364117239,hgt:197.287,std(0.000000,0.000000,0.000000)
bestpos:2082,133909200ms,type:1,lat:40.838053603,lon:14.364117239,hgt:197.287,std(0.000000,0.000000,0.000000)
bestpos:2082,133909400ms,type:1,lat:40.838053603,lon:14.364117239,hgt:197.287,std(0.000000,0.000000,0.000000)
bestpos:2082,133909600ms,type:1,lat:40.838053603,lon:14.364117239,hgt:197.287,std(0.000000,0.000000,0.000000)
bestpos:2082,133909800ms,type:1,lat:40.838053603,lon:14.364117239,hgt:197.287,std(0.000000,0.000000,0.000000)
Why the software in Mode1 should subtract the default APC height of the BASE receiver from the initial Z solution before reporting and use in the survey?
I am not a professional surveyor and I thought that for differential calculation it is essential to know the coordinates of the BASE receiver APC, no matter the height of the APC on the ground.
Is it another "strange" decision of the DJI engineers? Did you check such behaviour of the software?
Please help me to better understand your sentence. :-)
Cheers,
Maurizio
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