DSLWP-2 elements for GMAT?

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Ken Swaggart

23 Jun 2018 23 Jun '18

7:36 p.m.

Are the DSLWP-2 elements used by GMAT available somewhere? Google wasn't any help this time.

73, Ken, W7KKE

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Nico Janssen

24 Jun 24 Jun

3:04 a.m.

New subject: [amsat-bb] DSLWP-2 elements for GMAT?

Ken,

You can always find the most recent LongJiang 2 orbital elements for GMAT in my GMAT script for LongJiang 2 here: https://hamsat1.home.xs4all.nl/LongJiang2_NYC.script

For further information see my web page: https://hamsat1.home.xs4all.nl/index.html

By the way, I wonder why some people still continue to use the old outdated name 'DSLWP' for this satellite. The only real official name is 'LongJiang 2'. To make it worse, several variations of the old ID are now used. While the original IDs for the two satellites were DSLWP A1 and A2, you now also see DSLWP 1 and 2, and DSLWP A and B, etc. All confusion can be avoided by simply using the official name: 'LongJiang 2'. https://gbtimes.com/change-4-lunar-far-side-satellite-named-magpie-bridge-fr...

73, Nico PA0DLO

On 24-06-18 01:36, Ken Swaggart wrote:

...

Are the DSLWP-2 elements used by GMAT available somewhere? Google wasn't any help this time.

73, Ken, W7KKE

Sent via AMSAT-BB@amsat.org. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://www.amsat.org/mailman/listinfo/amsat-bb

Daniel Estévez

4:31 a.m.

New subject: [amsat-bb] DSLWP-2 elements for GMAT?

El 24/06/18 a las 09:04, Nico Janssen escribió:

...

By the way, I wonder why some people still continue to use the old outdated name 'DSLWP' for this satellite. The only real official name is 'LongJiang 2'.

Hi Nico,

DSLWP-B is the name currently used by Wei Mingchuan BG2BHC and all the information from Harbin Institute of Technology. I guess that this is the development name for the satellite, as it refers the the interferometry scientific payload.

The LongJiang name appeared only recently (shortly before launch I think), and I get the impression that this name was given for marketing reasons (but I might be wrong). In the same way, the Chang'e 4 relay was named Queqiao.

So personally I'm sticking with DSLWP-B, as Wei does.

73,

Dani.

Nico Janssen

5:32 a.m.

New subject: [amsat-bb] DSLWP-2 elements for GMAT?

Hi Dani,

The DSLWP names were indeed development names. As usual, most satellites have development names that are used pre-launch, and final names, that are used post-launch. So the DSLWP names were replaced by the official post-launch names LongJiang 1 and 2. This was done already in April: https://gbtimes.com/change-4-lunar-far-side-satellite-named-magpie-bridge-fr...

In the Satellite Catalog you will find the LongJiang names.

Obviously a lot of material, like software, was created before the launch, where the old name DSLWP was used. So I can imagine it is a lot of work to change that now. That is probably the reason the old name is still used now.

The name DSLWP-B is certainly wrong. If you insist on using the old name, then you should use DSLWP A2.

I'll stick to the official name LongJiang 2.

73, Nico PA0DLO

On 24-06-18 10:31, Daniel Estévez wrote:

...

El 24/06/18 a las 09:04, Nico Janssen escribió:

...
By the way, I wonder why some people still continue to use the old outdated name 'DSLWP' for this satellite. The only real official name is 'LongJiang 2'.

Hi Nico,

DSLWP-B is the name currently used by Wei Mingchuan BG2BHC and all the information from Harbin Institute of Technology. I guess that this is the development name for the satellite, as it refers the the interferometry scientific payload.

The LongJiang name appeared only recently (shortly before launch I think), and I get the impression that this name was given for marketing reasons (but I might be wrong). In the same way, the Chang'e 4 relay was named Queqiao.

So personally I'm sticking with DSLWP-B, as Wei does.

73,

Dani.

Sent via AMSAT-BB@amsat.org. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://www.amsat.org/mailman/listinfo/amsat-bb

Apostolos Kefalas

27 Jun 27 Jun

7:25 a.m.

New subject: [amsat-bb] DSLWP-2 elements for GMAT?

On Sun, 2018-06-24 at 09:04 +0200, Nico Janssen wrote:

...

Ken,

You can always find the most recent LongJiang 2 orbital elements for GMAT in my GMAT script for LongJiang 2 here: https://hamsat1.home.xs4all.nl/LongJiang2_NYC.script

For further information see my web page: https://hamsat1.home.xs4all.nl/index.html

Hello Nico,

I am trying to use your script for GMAT and learn a little bit of it. I am using GMAT R2018a 64bit for linux.

So far I have added a new "Ground Station" with the exact same "options" of "New_York_City", but with the coordinates of Athens (Lat:38.0246 , Lon:23.8442, Elev:0.230)

Also in the "Event Locators -> ContactLocator->Observers" I have unchecked New_York_City and checked Athens.

I run the Analysis and get the following:

Target: LongJiang2

Observer: Athens Start Time (UTC) Stop Time (UTC) Duration (s) 22 Jun 2018 20:00:01.308 22 Jun 2018 23:57:54.270 14272.962042 23 Jun 2018 13:30:48.606 24 Jun 2018 00:31:55.696 39667.090330 24 Jun 2018 14:29:38.778 25 Jun 2018 01:08:24.795 38326.017501 25 Jun 2018 15:29:40.410 26 Jun 2018 01:47:31.343 37070.933417 26 Jun 2018 16:25:59.568 27 Jun 2018 02:18:55.784 35576.216663 27 Jun 2018 17:18:46.946 28 Jun 2018 03:01:47.463 34980.517488 28 Jun 2018 18:07:27.244 29 Jun 2018 03:51:26.879 35039.635199 29 Jun 2018 18:51:47.025 30 Jun 2018 04:46:31.909 35684.884510 30 Jun 2018 19:31:54.199 01 Jul 2018 05:46:51.938 36897.739497 01 Jul 2018 20:08:14.499 02 Jul 2018 06:32:57.414 37482.914687

Number of events : 10

According to the above there should be a "pass" over my location on 27 Jun 2018 17:18:46.946 until 28 Jun 2018 03:01:47.463 (correct?)

But when I see the ReportFile1 I get:

........ (snip)

27 Jun 2018 17:23:32.914 150.5092511914209 NaN 419362.0357962959 282 97.22511514511 27 Jun 2018 17:40:29.154 142.0321174249796 NaN 418700.9067020232 282 97.23687717522 27 Jun 2018 18:00:10.948 133.4730126623195 NaN 417834.3036042269 282 97.25055535639 27 Jun 2018 18:18:31.981 126.6220879528141 NaN 416924.6852335503 282 97.26329879122 27 Jun 2018 18:33:21.680 121.7549078882987 NaN 416111.3291154901 282 97.27359622712 27 Jun 2018 18:48:06.639 117.4075174974269 NaN 415226.7124895696 282 97.28383881658 27 Jun 2018 19:01:35.422 113.7946111646366 NaN 414346.6042086262 282 97.29319973242 27 Jun 2018 19:13:46.677 110.7761388040548 NaN 413486.9471883456 282 97.30166332914 27 Jun 2018 19:24:48.083 108.217464063449 NaN 412653.1299510594 282 97.3093184835 27 Jun 2018 19:33:38.926 106.2647394891434 NaN 411942.9592179462 282 97.31546249967 27 Jun 2018 19:41:30.141 104.5965376382924 NaN 411280.9274945419 282 97.32091637599 27 Jun 2018 19:48:27.000 103.1654945120115 NaN 410670.3271268641 282 97.3257411411 27 Jun 2018 19:54:38.434 101.9214367116329 NaN 410107.171915261 282 97.3300401459

........ (snip)

Could please explain what am I doing wrong and I do not have an elevation calculation?

Thanks in advance Apostolos - SV1LJJ

Nico Janssen

9:08 a.m.

New subject: [amsat-bb] DSLWP-2 elements for GMAT?

Apostolos,

I don't think you are doing anything wrong. Your results look correct. But I cannot check everything because I am running the most recent version of the script with the 29 June orbital elements.

Sometimes I also get the 'NaN' result in the elevation column. I think this is a program bug. I found that sometimes it helps to do the following: stop GMAT, start GMAT, load the script, immediately run the script before doing anything else with the program.

I hope this helps.

73, Nico

On 27-06-18 13:25, Apostolos Kefalas wrote:

...

On Sun, 2018-06-24 at 09:04 +0200, Nico Janssen wrote:

...
Ken,

You can always find the most recent LongJiang 2 orbital elements for GMAT in my GMAT script for LongJiang 2 here: https://hamsat1.home.xs4all.nl/LongJiang2_NYC.script

For further information see my web page: https://hamsat1.home.xs4all.nl/index.html

Hello Nico,

I am trying to use your script for GMAT and learn a little bit of it. I am using GMAT R2018a 64bit for linux.

So far I have added a new "Ground Station" with the exact same "options" of "New_York_City", but with the coordinates of Athens (Lat:38.0246 , Lon:23.8442, Elev:0.230)

Also in the "Event Locators -> ContactLocator->Observers" I have unchecked New_York_City and checked Athens.

I run the Analysis and get the following:

Target: LongJiang2

Observer: Athens Start Time (UTC) Stop Time (UTC) Duration (s) 22 Jun 2018 20:00:01.308 22 Jun 2018 23:57:54.270 14272.962042 23 Jun 2018 13:30:48.606 24 Jun 2018 00:31:55.696 39667.090330 24 Jun 2018 14:29:38.778 25 Jun 2018 01:08:24.795 38326.017501 25 Jun 2018 15:29:40.410 26 Jun 2018 01:47:31.343 37070.933417 26 Jun 2018 16:25:59.568 27 Jun 2018 02:18:55.784 35576.216663 27 Jun 2018 17:18:46.946 28 Jun 2018 03:01:47.463 34980.517488 28 Jun 2018 18:07:27.244 29 Jun 2018 03:51:26.879 35039.635199 29 Jun 2018 18:51:47.025 30 Jun 2018 04:46:31.909 35684.884510 30 Jun 2018 19:31:54.199 01 Jul 2018 05:46:51.938 36897.739497 01 Jul 2018 20:08:14.499 02 Jul 2018 06:32:57.414 37482.914687

Number of events : 10

According to the above there should be a "pass" over my location on 27 Jun 2018 17:18:46.946 until 28 Jun 2018 03:01:47.463 (correct?)

But when I see the ReportFile1 I get:

........ (snip)

27 Jun 2018 17:23:32.914 150.5092511914209 NaN 419362.0357962959 282 97.22511514511 27 Jun 2018 17:40:29.154 142.0321174249796 NaN 418700.9067020232 282 97.23687717522 27 Jun 2018 18:00:10.948 133.4730126623195 NaN 417834.3036042269 282 97.25055535639 27 Jun 2018 18:18:31.981 126.6220879528141 NaN 416924.6852335503 282 97.26329879122 27 Jun 2018 18:33:21.680 121.7549078882987 NaN 416111.3291154901 282 97.27359622712 27 Jun 2018 18:48:06.639 117.4075174974269 NaN 415226.7124895696 282 97.28383881658 27 Jun 2018 19:01:35.422 113.7946111646366 NaN 414346.6042086262 282 97.29319973242 27 Jun 2018 19:13:46.677 110.7761388040548 NaN 413486.9471883456 282 97.30166332914 27 Jun 2018 19:24:48.083 108.217464063449 NaN 412653.1299510594 282 97.3093184835 27 Jun 2018 19:33:38.926 106.2647394891434 NaN 411942.9592179462 282 97.31546249967 27 Jun 2018 19:41:30.141 104.5965376382924 NaN 411280.9274945419 282 97.32091637599 27 Jun 2018 19:48:27.000 103.1654945120115 NaN 410670.3271268641 282 97.3257411411 27 Jun 2018 19:54:38.434 101.9214367116329 NaN 410107.171915261 282 97.3300401459

........ (snip)

Could please explain what am I doing wrong and I do not have an elevation calculation?

Thanks in advance Apostolos - SV1LJJ

Sent via AMSAT-BB@amsat.org. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://www.amsat.org/mailman/listinfo/amsat-bb

Apostolos Kefalas

9:13 a.m.

New subject: [amsat-bb] DSLWP-2 elements for GMAT?

Thank you Nico,

i will try it again.

73, Apostolos

On Wed, 2018-06-27 at 15:08 +0200, Nico Janssen wrote:

...

Apostolos,

I don't think you are doing anything wrong. Your results look correct. But I cannot check everything because I am running the most recent version of the script with the 29 June orbital elements.

Sometimes I also get the 'NaN' result in the elevation column. I think this is a program bug. I found that sometimes it helps to do the following: stop GMAT, start GMAT, load the script, immediately run the script before doing anything else with the program.

I hope this helps.

73, Nico

On 27-06-18 13:25, Apostolos Kefalas wrote:

...
On Sun, 2018-06-24 at 09:04 +0200, Nico Janssen wrote:

...
Ken,

You can always find the most recent LongJiang 2 orbital elements for GMAT in my GMAT script for LongJiang 2 here: https://hamsat1.home.xs4all.nl/LongJiang2_NYC.script

For further information see my web page: https://hamsat1.home.xs4all.nl/index.html

Hello Nico,

I am trying to use your script for GMAT and learn a little bit of it. I am using GMAT R2018a 64bit for linux.

So far I have added a new "Ground Station" with the exact same "options" of "New_York_City", but with the coordinates of Athens (Lat:38.0246 , Lon:23.8442, Elev:0.230)

Also in the "Event Locators -> ContactLocator->Observers" I have unchecked New_York_City and checked Athens.

I run the Analysis and get the following:

Target: LongJiang2

Observer: Athens Start Time (UTC) Stop Time (UTC) Duration (s) 22 Jun 2018 20:00:01.308 22 Jun 2018 23:57:54.270 14272.962042 23 Jun 2018 13:30:48.606 24 Jun 2018 00:31:55.696 39667.090330 24 Jun 2018 14:29:38.778 25 Jun 2018 01:08:24.795 38326.017501 25 Jun 2018 15:29:40.410 26 Jun 2018 01:47:31.343 37070.933417 26 Jun 2018 16:25:59.568 27 Jun 2018 02:18:55.784 35576.216663 27 Jun 2018 17:18:46.946 28 Jun 2018 03:01:47.463 34980.517488 28 Jun 2018 18:07:27.244 29 Jun 2018 03:51:26.879 35039.635199 29 Jun 2018 18:51:47.025 30 Jun 2018 04:46:31.909 35684.884510 30 Jun 2018 19:31:54.199 01 Jul 2018 05:46:51.938 36897.739497 01 Jul 2018 20:08:14.499 02 Jul 2018 06:32:57.414 37482.914687

Number of events : 10

According to the above there should be a "pass" over my location on 27 Jun 2018 17:18:46.946 until 28 Jun 2018 03:01:47.463 (correct?)

But when I see the ReportFile1 I get:

........ (snip)

27 Jun 2018 17:23:32.914 150.5092511914209 NaN 419362.0357962959 282 97.22511514511 27 Jun 2018 17:40:29.154 142.0321174249796 NaN 418700.9067020232 282 97.23687717522 27 Jun 2018 18:00:10.948 133.4730126623195 NaN 417834.3036042269 282 97.25055535639 27 Jun 2018 18:18:31.981 126.6220879528141 NaN 416924.6852335503 282 97.26329879122 27 Jun 2018 18:33:21.680 121.7549078882987 NaN 416111.3291154901 282 97.27359622712 27 Jun 2018 18:48:06.639 117.4075174974269 NaN 415226.7124895696 282 97.28383881658 27 Jun 2018 19:01:35.422 113.7946111646366 NaN 414346.6042086262 282 97.29319973242 27 Jun 2018 19:13:46.677 110.7761388040548 NaN 413486.9471883456 282 97.30166332914 27 Jun 2018 19:24:48.083 108.217464063449 NaN 412653.1299510594 282 97.3093184835 27 Jun 2018 19:33:38.926 106.2647394891434 NaN 411942.9592179462 282 97.31546249967 27 Jun 2018 19:41:30.141 104.5965376382924 NaN 411280.9274945419 282 97.32091637599 27 Jun 2018 19:48:27.000 103.1654945120115 NaN 410670.3271268641 282 97.3257411411 27 Jun 2018 19:54:38.434 101.9214367116329 NaN 410107.171915261 282 97.3300401459

........ (snip)

Could please explain what am I doing wrong and I do not have an elevation calculation?

Thanks in advance Apostolos - SV1LJJ

Sent via AMSAT-BB@amsat.org. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://www.amsat.org/mailman/listinfo/amsat- bb