How to properly configure NS-HP-GN2 : PX1122R ?

[telemach]

I use this module as a rover; it is connected to bluetooth uart so can communicate with Android app - NTRIP Client which is streaming corrections from CORS (via internet) available/usable corrections are 1004, 1012, 1033 and serving mock location to Android map app

Antenna used is ANN-MB from U-blox

I often place antenna in one spot and expect precise location within max 30-50cm range from real location

Problem is that whatever I do I can't get NS-HP-GN2 to deliver that; there is a problem with multipath and even if I manage to get RTK or Float RTK it is clearly not near the real location but somewhere few meters away from real location; I do have 30 sats in view with good signal

For comparison I use Ublox NEO-7P with L1 GPS only, 6 to 8 sats in view and RTCM 2.3 corrections that result in DGPS and it beats NS-HP-GN2 with precision and multipath so please help me configure this module to perform best it can

I can only imagine that these settings might influence that : DOP Mask, Update Rate, Navigation Mode, Noise Power Control, Interference Detect Control

If you guide me what to configure I can deliver GPS/NTRIP data so you can inspect by yourself.

[ESPrtk]

How far from the NTRIP Base to your Rover ?
RTCM 1004/1012/1033 is old RTCM 3.0 but OK.
Why you don't use another PX1122R to build your own as NTRIP Base to get more RTCM MSM type ?

[telemach]

->How far from the NTRIP Base to your Rover ?

less than 7 Kilometers

->Why you don't use another PX1122R to build your own as NTRIP Base to get more RTCM MSM type ?

because it is not cheap and I don't have such requirements that will pay off this investment;
I have original NS-HP-5 but even if that will base with MSM messages how can I be sure of
correct measurements if without NTRIP corrections this module can't provide stable and accurate position ?

I don't need centimeter postion, I need decimeter position BUT stable with minimal multipath and accurate and not precise but meters away

I see different options in software so seek some help in choosing the right ones to get the result I am looking for.

[Andrew Hsu]

Hi,

If the corrections from CORS do not have enough satellites, the rover with baseline length as large as 7 Kilometers may have difficulty to get RTK fix or true position. Can you save the data of base and rover for analysis?

Best regards,

Andrew

[telemach]

sure I can, just instruct me if you want me to do factory defaults or setup something before gathering data ?

[Andrew Hsu]

Hi,

1. Please do a factory reset to your NS-HP-GN2.
2. Please configure NS-HP-GN2 to base mode. Viewer->RTK->Configure RTK Mode and Operational Function

configure_rtk_base.png (17.66 KiB) Viewed 8023 times

3. Please configure NS-HP-GN2 RTCM. Viewer->Raw->Configure RTCM Measurement Data Output.

configureRTCM.png (19.48 KiB) Viewed 8023 times

4. Please log RTCM data output of NS-HP-GN2: Viewer->File->Save Device Output.

filesave.png (10.08 KiB) Viewed 8023 times

5. Please log base from CORS RTCM data for 15 minutes simultaneously as item 4. You may use RTK lib strsvr to save to a file.

Best regards,

Andrew

[telemach]

I attach files you requested.
Antenna was placed on an elevated manhole that provides excellent ground plane.

[Andrew Hsu]

Hi,

After our analysis,

Since your CORS has only GPS+Glonass, the same satellites of GPS and Glonass on the rover side are too less for RTK to have stable and accurate fix. RTK post processing showed 6 SV in RTK fix or float solution. Besides, your testing time at your location was at the time when Glonass has the fewest SV (3 with elevation mask 15 ) shown as picture below,

glonass_SV.png (33.27 KiB) Viewed 7361 times

Here are our suggestions that you may try,

1. Change constellation type to GPS+Glonass, Viewer-> Venus 8-> Configure GNSS constellation type

configure_GNSS_const_1.png (108.61 KiB) Viewed 7361 times

configure_GNSS_const_2.png (68.53 KiB) Viewed 7361 times

2. Change elevation mask to 5 degree, Viewer->Binary-> Configure Elevation and CNR mask

configure_elv_1.png (147.5 KiB) Viewed 7361 times

configure_elv_2.png (81.45 KiB) Viewed 7361 times

3. Find some other time with more GPS/Glonass satellites to conduct the test.
4. Power on wait 15 minutes to get more satellites.

Best regards,

Andrew

[telemach]

Sure I will do another test but from what I see the situation with your module is alarming because it means there are only two states of operation
very bad and very good so nothing in between. I would expect that even without any corrections this multi constellation module with decent antenna and ground plane can provide efficient and accurate position but it turns out only RTK under specific conditions is reliable. Once again with Neo 7P it can be raining, I can stay under the tree or drive the car and DGPS is accurate enough to show me under what tree I am standing or what lane I am driving and it's using only 1 constellation.

[telemach]

measurements from today (different location)