The new Indian satellite INSAT-3DS

[sergsero]

In the near future an ISRO GSLV-II rocket will launch the new Indian satellite INSAT-3DS . The launch date is currently targeted for November 01, 2023 (UTC).

There is no file for earlier Indian INSAT-3DR among the pipelines.

Is this due to some circumstances of decoding signals from these satellites, besides the fact that the downlink transmission is in the extended C-band, near 4.78 GHz?

[Aang23]

The reason is just that nodody has ever provided data I could work off to implement a decoder. If you are able to receive it, I don't see why it would not be possible though.

Raw data and HRIT should be on C-Band.

[sergsero]

I tried to receive signals from INSAT-3DS at frequencies of 4798 MHz (SOUNDER) and 4781 MHz (IMAGER).

My LNB has LO=5950 MHz, so the reception frequencies were 1152.465 MHz and 1169.465 MHz.

I tried the HRIT processing options from different satellites for "IMAGER" and some SNR values were displayed for "GK-2A HRIT". For "SOUNDER" some values were obtained in the mode from "GOES-N Sounder SD".

I recorded the signals in s8 format. I don't know if these records will be useful for development.

SOUNDER https://drive.google.com/file/d/1A0y2enabf22Sp11pIpt0cJT38xNkFX-V/view?usp=sharing IMAGER https://drive.google.com/file/d/1A-5IvtMwsm9I_UstJBTVVdYGSAQEBGsk/view?usp=sharing IMAGER https://drive.google.com/file/d/1A1FGtM0wI39WZAbmrwXs9wMSjucTQv2j/view?usp=sharing IMAGER https://drive.google.com/file/d/1A1XU19XjT5eD1C9OEwcSli_46d_BKdaN/view?usp=sharing

Unfortunately, the SNR value of 5-6 dB for "HRIT" seems to be the maximum that can be obtained on the my setup for this satellite. I hope this will prove useful.

[sergsero]

Today I checked the signal receiving from Insat-3dr again after accurate guidance of antenna on the target satellite and it was slightly better by 1-2 dB, but still does not reach SNR 7 dB on the GK-2A HRIT scale.

[sergsero]

Launch Overview: Liftoff Time - November 01, 2023 +07 (00:00 UTC).

Mission Overview: INSAT-3DS is an Indian weather satellite built by the Indian Space Research Organization and operated by ISRO as part of the Indian National Satellite System. It provides meteorological services to India using a 6-channel imager and a 19-channel sounder, as well as search and rescue information and message relay for terrestrial data collection platforms. The satellite will be a follow-up to INSAT-3DR.

[sergsero]

There are two different modes in the transmission. Probably one of its contains data. Initially, it was assumed that this is hrit. Now it's probably a raw stream.

[sergsero]

I checked if there is still signal reception from Insat-3dr and made two .s8 recordings of 6 MSpS samplerate. I still hope that they will prove useful and that someday the possibility of decoding the will be implemented.

2023-12-17_06-33-41_6000000SPS.s8.tgz https://drive.google.com/file/d/1oNGbgWKL_W6zB6ZN3GYbgYTBzqnCqxt6/view?usp=drive_link 2023-12-17_07-12-43_6000000SPS_1.s8.tgz https://drive.google.com/file/d/1oSab218smbWtqWv3vALb8FlUfTOOa1_L/view?usp=drive_link

[Aybarnur]

I also recorded the baseband from insat3dr via the same C-band antenna LNB LO=5.95 GHz (5950-4780.5=1169.5): 2023-12-18_08-46-20_6000000SPS_1169500000Hz.s8 (~6.55GB). https://drive.google.com/file/d/1gIcR4isM5dz5efmReq69hhhkVPJh2sxE/view?usp=drive_link

To avoid DC-spike, the receiver's tune was 50 kHz lower in frequency from the signal carrier.

For these gain's values, the constellation does not yet become square.

[Aybarnur]

INSAT-3DS - 4th orbital launch attempt Launch Time: Wed Jan 10, 2024 18:30 GMT+7

[sergsero]

It's a new recording of the C-band signal on 4781 MHz in the format .s8 with duration of 15 minutes and size 15 GB. 2024-01-01_07-00-00_8000000SPS_1169500000Hz.s8. https://drive.google.com/file/d/1oiuooMTEYzGb1DNNzZt_UIIFpt2HIG7z/view?usp=drive_link

I noticed that the transmission is cyclical. It starts at the 15th minute of every hour and lasts until the 40th.

From the 11th minute to the 14th, the first type of signal with the maximum amplitude is transmitted.

Starting from the 15th minute to the 40th, it looks like basic data is being transmitted.

And from the 41st to the 44th minute there is the same transmission mode as "11-14".

Recently implemented in HackRF function for adjusting the filters help block out of band interference. It's very useful, thank you so much! I hope that it will be useful and someday there will be an opportunity to get not only .soft-file, but also images from the Insat-3dr.

[sergsero]

The launch of the GSLV-F14/INSAT-3DS mission is set for Saturday, February 17, 2024, at 17:30 Hrs. IST from SDSC-SHAR, Sriharikota. In its 16th mission, the GSLV aims at deploying the INSAT-3DS meteorological satellite into the Geosynchronous Transfer Orbit (GTO). Subsequent orbit-raising maneuvers will ensure that the satellite is positioned in a Geo-stationary Orbit.

The Satellite carries 6 Channel Imager, 19 Channel Sounder payload, Data Relay Transponder(DRT)and Satellite aided Search and Rescue (SA&SR) transponders. Imager and Sounder payloads are similar to the payloads flown on INSAT-3D and INSAT-3DR with significant improvements in radiometric performances.

https://www.isro.gov.in/media_isro/pdf/Missions/GSLVF14/GSLVF14-INSAT-3DS_Brochure_English.pdf

[Aybarnur]

ISRO's INSAT-3DS, aboard a GSLV rocket, successfully launched from Sriharikota. "The vehicle has successfully placed the satellite into the intended geosynchronous transfer orbit. The satellite will augment the meteorological services along with the presently operational INSAT-3D and INSAT-3DR satellites", ISRO said.

Unfortunately, processing data from that satellite is not a priority, as the authors explained to me.

Nevertheless, with the hope that someday this time will come, Insat-3DR satellite Imager: insat3dr_20240218_043551_10MSPS.s16.tgz (8479MB) https://drive.google.com/file/d/1SOd0SFbI2kHCn1afftxhR2GRpgXUUDOT/view?usp=drive_link

insat3dr_20240218_044126_10MSPS.s16.tgz (1680MB) https://drive.google.com/file/d/1aS59t60r2fc2DwqeUJMBSxyRzBOE6GvM/view?usp=drive_link

[Aybarnur]

12 MSPS .soft 1 hour and 20 minutes. The file size is 34 GB: https://drive.google.com/file/d/1_7SHpzMDoAFytrDFS4h1FG5P1rHb5l-g/view?usp=drive_link

1 hour and 50 minutes. The file size is 46 GB: https://drive.google.com/file/d/1wLAYyKCyMui8O5k_FPr11k8COWD7cfwq/view?usp=drive_link

[Aang23]

Thanks!

[Aang23]

@sergsero it is likely 3DS will use some slightly newer protocols if it follows the general trend of Indian missions.