What't the height of antenna, GNSS Multi-Band L1/L2 Surveying Antenna - TNC (TOP106)

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1

Hi technical team,

Could you let me know the height of antenna from bottom?
We have two sparkfun RTK surveyor units and the model of antennas is TOP106
There is a figure in the antenna below.

Figure of heights
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Please let me know which number is the height of this antenna from bottom, 43.50mm or 39.50mm?
I’m conducting topgraphic survey and using this RTK GPS to check ellipsoidal height. The Reduced Level of ground service equals to = surveyed height - pole height - antenna height. Thanks heaps.

2

Both! :slight_smile:
They are L1 & L2, respectively

image
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3

Hi Russell,

Thanks for you quick reply.
could you let me know whether the band I am using is L1 or L2?
I’m in Australia and when I use this RTK GPS, I pair the GPS to app SW Maps via bluetooth, then collect the app to Allday RTK to get an accuarate GNSS height.

4

Since the TOP106 has a NGS Calibration, we should be using that instead of the Mechanical Phase Centers.

The actual Antenna Phase Centers for L1 and L2 frequencies are points in space above the Mechanical Antenna Phase Center.

From the TOP106 Calibration File:

Actual L1 Phase Center
2.66 North, -3.23 East, 52.94mm Up (verses 43.6mm Mechanical)

Actual L2 Phase Center
-0.29 North, 3.54 East, 48.05mm Up (verses 39.6mm Mechanical)

Source:

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For general RTK work, it’s hard to get everyone to agree on which offset to apply, and in reality it doesn’t matter all that much due to the actual precision & accuracy of typical RTK solutions. But you are introducing ~1cm of systematic error (Mechanical vs Actual) by not using the Actual Phase Center for the TOP106 per the NGS Calibration.

For Static Sessions, the calibration becomes very important.

But to answer your question for RTK work, I personally use the actual L2 phase center at 48mm above ARP per the NGS calibration file.

When using a different antenna without NGS calibration, you are forced to stick with the Mechanical Phase Center, per it’s dwg.

6

Since I was already on the NGS page :

The Facet - SFEFACET
Actual L1 Phase Center
2.46 N -0.93 E 71.84 UP

Actual L2 Phase Center
2.21 N 5.44 E 67.25 UP

The Tri-Band - SFESPK6618H
Actual L1 Phase Center
0.47 N -1.26 E 48.02 UP

Actual L2 Phase Center
2.73 N -1.87 E 35.91 UP

Actual L5 Phase Center
3.16 N -2.02 E 36.91 UP

But please verify the numbers before you use them :face_with_peeking_eye:

7

Thanks heaps rftop. It looks like that this question is more complicated than I though :smile:
Could you check which number I could use in Melbourne Vicotoria Australia if possible? Thanks for supplying these data but I cannot interprete them.

8

When using the RTK surveyor and it’s TOP106 antenna, Add 48mm to your Pole Height measurement in your data collector software of choice.

IE: if your Rod is actually a true 2.000 meters, enter 2.048 meters as the Rod Height to account for the L2 Phase Center.

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9

Thanks a lot mate.

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