Is the UM982 an F9P killer for AOG?

GPS / RTK / GNSS
74

Is there a post from potatofarmer with his findings for the UM982? Don’t want to plow any already plowed fields. :wink:

75

Taged him for converting cords to needed datum. Seen him write hire about that stuff.

No one did true accuracy test with um982. As far as I am awere.

76

tried to send a command to enable mmp. failed on um982. Applicable to: UM980 writed in Unicore_Reference_Commands_Manual_For_N4_High_Precision_Products_V2_EN_R1_1.pdf
$command,CONFIG MMP ENABLE,response: PARSING FAILD MISSING FIELD,*1D

77

Try lower case. I have seen some commands don’t work when uppercase. I always use lowercase. What version firmware does the UM982 have?

Here is my version string.
#VERSION,96,GPS,FINE,2285,474910000,0,0,18,456;UM982,R4.10Build9984,HRPT00-S10C-P,2310415000012-LR23B2224524818,ff274098521ef48b,2023/06/01*d73ea184

78

lower case not helped. How to update fw version?
#VERSION,97,GPS,UNKNOWN,1,105300,0,0,18,96;UM982,R4.10Build7650,HRPT00-S10C-P,2310415000012-LR23B2224524831,ff27d4987076f87c,2022/09/01*289ad0d7

79

Here is the procedure I used;

Do an freset to reset to factory defaults. Make note of your current settings.
Connect with Uprecise. Do an unlogall for COM1, COM2 and COM3.
Use the update function in Uprecise. I had to do it twice before it worked. Some of the upgrade GUI is still in Chinese even though I have the GUI set to english. I cut and pasted them into Google translate when needed.

Here is version 9984.
UM982_R4.10Build9984.pkg.zip (2.1 MB)

80

Thanks, now mmp enabled

81

Glad to hear it. Enabling it improved the stability of the readings for me.

82

Have you seen the SMOOTH setting? what does this mean?

83

It seems to do a continuous rolling average of the past N seconds of readings. I tried it and it made the GPS appear to lag behind the actual position slightly. I tested it with google maps which are not the most accurate either. The path on the map did look smoother.

Might be useful for folks using the slow poke version of AOG since they are moving at a snails pace.

84

Slow poke is pretty much done and committed, well past worrying about slow speed now :slight_smile:

85

if I may ask, do you have any direct line with Unicore? How are you getting those docs and firmwares?

86

The manuals are available on the Unicore public site. Make sure you are on the English site versus the Google translation of the Chinese site. There are more items available for download on the English site. The english site URL’s start with “en”.

Also, the manuals can be quite long and sometimes less than clear so read them carefully and completely. There is a lot of good info in the 300 page command manual. They can be out of date with regards to build numbers or model numbers that support a function so you just have to try the function sometimes.

1 Like
87

Is it correct that UM982 cannot roll in contrast to Dual F9P?

88

regarding dual antenna roll angle, see: Is the UM982 an F9P killer for AOG? - #38 by chri5k

89

To clarify, the F9P calculates the North East Down (NED) vector and baseline between the position receiver (moving base) and the heading receiver. This information is encoded into a NAV-RELPOSNED packet. The AOG firmware uses the information in this packet to calculate dual roll . The firmware only uses the results of the calculation when the receiver has an RTK Fixed solution. This can be found in the zRelPos.ino file in the AOG firmware repository.

The UM982 outputs Earth Centered Earth Fixed (ECEF) coordinates for the position antenna and the heading antenna. There are c++ routines for converting ECEF coordinates into a NED vector and baseline on the Teensy. This data can be used to calculate roll in the same manner as the F9P.

Attached are the c++ coordinate conversion routines header file I have been using. I did not create these routines. Someone way smarter than me created them and posted them on OnlineGBD. I did check the formulas against the NOAA references and they appear to be correct. I also changed the floats to doubles since the Teensy handles doubles with more precision.

conv_coord.h.zip (4.4 KB)

1 Like
90

What VCC (power supply voltage) is the UM982eb module good for? I’ve seen 3.3-7V and 3.3-5.5V. Also, what voltage levels are it’s IO?

edit
How much power does it need on the supply, is a 1A switching buck sufficient?
What “polarity” is pin 21 PVT_STAT?

91

The spec sheet for the evaluation board I have says min 3.3v and max 5.5v. The spec sheet for the UM982 chip says max 3.6v. I run mine at 3.3v. Min current for the evaluation board at 3.3v is listed as 150ma and max 250ma. The one I am running right now shows it is drawing 340ma.

COM port IO is at the LVTTL (3.3v) level. PVT_STAT is driven HIGH to VCC - 0.45 volts when positioning.

92

Thanks for those numbers. So I expect the eval board has a LDO or buck regulator. Are you running a bare chip or eval board? When you say “when positioning”, you mean it has a fixed/locked position? You’d use an LED to ground to indicate that it’s “working”?

93

I have an eval board. Looks like it has a regulator / buck of some sort.

By “positioning” I mean the UM982 is receiving satellite signals and is working on a position solution. I wouldn’t say fixed / locked since it could be producing a DGPS, RTK Float, Wide-lane or some other position solution. To me fixed means an RTK INT fix with sub-centimeter accuracy.

There is an RTK light on my eval board that lights up when it has an RTK fix of some sort, either float or int. Pad 25 on my board is for RTK_STAT but has no pin soldered in to it. I would put a current limiting resistor in series with the LED. Those outputs are good for something like 2 mA.

Earlier in this thread I posted all of the manuals and data sheets I have. The numbers are in those documents.