Observation 12437739: LAPAN-A2 (40931) - Need Update TLE

Satellites & Observations Observations
1

Regarding Observation 12437739 …

the TLE data for lapan-a2 from space-track, is too old and not accurate. below i check using strf app by @cgbsat

fit process
fit process867×669 61.8 KB

mean anomaly fit
mean anomaly fit867×669 63.3 KB

867×669 62.9 KB

from TCA we know there is different 2 minutes between old and new custom TLE

867×669 118 KB

867×669 65.8 KB

867×669 66.6 KB

test for APRS and its valid:

09-test-aprs
09-test-aprs1198×669 44.5 KB

below is the LTE correction from above apps, and it work and tested :

LAPAN-A2                
1 40931U          25151.18580175  .00000000  00000-0  78118-4 0    08
2 40931   6.0006  24.0987 0012733 338.8432  13.6990 14.78805930    01
# 20250926.41-20250926.41, 302 measurements, 0.051 kHz rms

maybe @ferdy can add this LTE into satnodgs local database, for temporary solution.

thank you!

2 Likes
2

HI,
If I see things right you are trying to match an TLE to a radio transmitter transponder output. Keep in mind that if the transmitting station is not using frequency correction matching the exact doppler curve the output you see in the modulated signal never can match the actual TLE>

Did you check the age of the TLE you are using ?

Nice to see another one jumping into the STRF tools by the way !

Regards,
Ben

1 Like
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tle-old
tle-old349×236 19.2 KB

4

i’m just want ask satnogs admin to update the TLE. i use the STRF just for refit / update the current Lapan A2 TLE. so it will help make best observation for ground station

5

I can confirm LAPAN-A2 TLE data was way off (almost 2 minutes) and the TLE that was used is also more than a month older as the last update does not improve the accuracy.

Here’s one of the observation, you can see the Doppler correction was really off :slight_smile:

3 Likes
6

I echo your statement… We here in Brazil are delighted to have two active transponder passes over the weekend (one on Saturday and one on Sunday), and several operators have noticed a difference of about two minutes between the old TLE and the actual satellite position.

I have been providing an updated TLE to Brazilian operators every Friday so that we have an updated TLE before the satellite pass.

Screenshot_43
Screenshot_43794×582 106 KB

3 Likes
7

The TLE has been added, however it uses the epoch of the previous one so it will not be shown as the latest… let me see if I can fix this with using observations from the Network.

By the way it would be very helpful if you can also share the .dat file and the sites.txt files (or whatever are they named). This way we can verify and re-use these data. :wink:

8

Based on @bali TLE and using some Network’s observations here is a TLE with propagated epoch:

LAPAN-A2
1 40931U          25268.61359892  .00000000  00000-0  78118-4 0    05
2 40931   6.0006 257.9450 0012733 338.8432 104.2918 14.78961520    08

lapana2_269_v1.dat (1.5 KB)
sites.txt (11.6 KB)

EDIT: I’ve also scheduled a couple of observations to verify the new TLE sets.

1 Like
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this my file:
LAPAN2.dat (12.4 KB)
sites.txt (3.3 KB)

shot
shot867×669 7.08 KB

1 Like
10

thank you!

11

We have a MUCH better TLE (See this observation)

FM repeater active in northern South America (Me “PU4ELT” appear at minute 4:43 :grin:)

1 Like
12

LAPAN-A2 has a lost status, so isn’t being updated by space-track and celestrak.

image
image854×141 15.5 KB

I am unable to receive the satellite so I can’t create/update the TLE.

Jan | PE0SAT

1 Like
13

haha. i’m observe this. very good station. everyone call papa :smiley: finally i hear you mention your callsign.

1 Like
14

make me wonder, why the status is lost.

15

Where can I get hold of software which will display information as well as that displayed above? I run Linux on my main PC and Windows 11 on my laptops. I’m not a fan of Windows, but sometimes there is no other option. Thanks
Bob VK2BYF

16

the best thing is it for linux only

and recommended tutorial here:

17

Thanks bali,
Good ol’ github
Bob

18

Objects with low inclination are not very well tracked by space-track.org. For example Galassia-2, NuLIoN and VELOX-AM had similar issues. So, we can help these missions by generating TLE sets for them based on our observations.

1 Like
19

thank you for the answer.