Why is there so much TLE confusion when new Cubesats are launched?

Every time a CubeSat gets launched, there is some confusion on what TLEs should be used.   This is the result of the process of launching a new amateur CubeSat with other CubeSats, often several dozen at a time.  We then start the  process of determining which object in a “flock” of CubeSats  is associated with a particular spacecraft.

Pre-launch TLEs that are calculated based on the expected orbit are usually supplied by the launch provider. Pre-launch TLEs are used until post-launch TLEs (for the group of objects that your satellite is in) are released from the US Department of Defense Joint Space Operations Center (JSpOC) based on observations made with cameras and radars.

There is a a 5 to 10 day period of tracking a group of CubeSats until they separate enough to isolate the one of interest. By observing the Doppler shift on transmissions from a particular satellite against the calculated Doppler shift from all candidate object TLEs, we can positively associate an object with a particular satellite. In the case of AMSAT satellites, we then advise JSpOC which object number is “ours”.

Finally, an individual satellite and its associated TLEs are determined and we settle down to an single, accurate, reliable set of TLEs … and all the other “best guesses” go away, although they may be still floating around on the Internet. But, there are so many variables  – did you launch on time, did you get released on time, has the group your CubeSat is in separated enough to identify your satellite, etc. that the process that can be both confusing and annoying at the same time.

AMSAT strives to minimize confusion when distributing TLEs.  Dummy object numbers are used for pre-launch TLEs since final object numbers cannot be assigned yet.    Immediately post launch we may post candidate objects with generic names like “OBJECT C”.    Finally, when positive association between an object number and a spacecraft is made, we will use the common name of the satellite.   We always recommend using TLEs from the Keps mailing list or the current bulletin or bare elements from the AMSAT web site.

 

by Ray Hoad
WA5QGD
Orbital Elements Manager

 

 

FoxTelem Version 1.06 Released

​I am releasing version 1.06 of FoxTelem today.  This release addresses several defects and instabilities in FoxTelem 1.05 and earlier.  It also introduces a new Earth Plot that allows any telemetry value to be plotted as a heat map against a map of the earth.  For more details about the Earth Plot and some example plots, you can read a quick tutorial that I have written here:
http://www.g0kla.com/workbench/2018-01-26.php

As always, let me know if you see any issues or log them on Github at https://github.com/ac2cz/FoxTelem/issues

KEY CHANGES
~~~~~~~~~~~
* EARTH PLOTS allow you to plot any telemetry value as a heat map on a map of the earth
* Allow graphs and telemetry results to be searched with UTC dates and for ranges of uptime/dates
* Allow stepping through the telemetry with up/down arrows
* Prevent hang when decoder starts if FCD returns an error
* Fixed bug where TLEs were not updated in the name is changed in the spacecraft settings window
* Fixed crashes introduced in 1.05 release
* Display all HERCI High Speed payloads when Raw Byte Payloads shown.
* Fix bug where missing TLE disables spacecraft from being tracked at all
* Fixes bug where DDE connection to SatPC32 fails with European decimal point format
* Add MPPT calibration values for Fox-1D
* Improved the RF signal measurements
* Improved the Find Signal algorithm
* Space graph labels more evenly
* Put the spacecraft tabs in FoxId order

And many other bug fixes. Full list of changes here:
https://github.com/ac2cz/FoxTelem/milestone/3?closed=1

You can download the latest version of the program from:

AO-92 Commissioned, Open for Amateur Use

On the 03:25 UTC pass on January 26, 2018, AMSAT Vice President – Engineering Jerry Buxton, N0JY, announced that AO-92 had been commissioned and formally turned the satellite over to AMSAT Operations. AMSAT Vice President – Operations Drew Glasbrenner, KO4MA, then declared that AO-92 was now open for amateur use. Audio of the handover and first operational pass can be heard here:

 

Initially, the U/v FM transponder will be open continuously for a period of one week. After the first week, operations will be scheduled among the U/v FM transponder, L-Band Downshifter, Virginia Tech Camera, and the University of Iowa’s High Energy Radiation CubeSat Instrument (HERCI).

Schedule updates will appear in the AMSAT News Service Weekly Bulletins and will also be posted to the AMSAT-BB, AMSAT’s Twitter account (@AMSAT), the AMSAT North America Facebook group, and the AMSAT website at https://www.amsat.org/satellite-schedules/

AO-92 was launched on the PSLV-C40 mission from Satish Dhawan Space Centre in Sriharikota, India on January 12, 2018. For the past two weeks, the AMSAT Engineering and Operations teams have been testing the various modes and experiments on board. Testing has shown that both the U/v FM transponder and L-Band Downshifter work very well. The Virginia Tech camera has returned stunning photos and data from HERCI has been successfully downlinked.

AMSAT thanks the 178 stations worldwide that have used FoxTelem to collect telemetry and experiment data from AO-92 during the commissioning process. The collection of this data is crucial to the missions of AMSAT’s Fox-1 satellites. Please continue to collect data from AO-85, AO-91, and AO-92.

Radio Programming Charts

AO-92 Doppler Shift Correction (Mode U/v)

Memory

Your Transmit Frequency

(With 67 Hz Tone)

Your Receive Frequency

Acquisition of Signal (AOS) 435.340 MHz 145.880 MHz
Approaching 435.345 MHz 145.880 MHz
Time of Closest Approach (TCA) 435.350 MHz 145.880 MHz
Departing 435.355 MHz 145.880 MHz
Loss of Signal (LOS) 435.360 MHz 145.880 MHz

AO-92 Doppler Shift Correction (Mode L/v)

Memory

Your Transmit Frequency

(With 67 Hz Tone)

Your Receive Frequency

Acquisition of Signal (AOS) 1267.320 MHz 145.880 MHz
Approaching 1 1267.325 MHz 145.880 MHz
Approaching 2 1267.330 MHz 145.880 MHz
Approaching 3 1267.335 MHz 145.880 MHz
Approaching 4 1267.340 MHz 145.880 MHz
Approaching 5 1267.345 MHz 145.880 MHz
Time of Closest Approach (TCA) 1267.350 MHz 145.880 MHz
Departing 1 1267.355 MHz 145.880 MHz
Departing 2 1267.360 MHz 145.880 MHz
Departing 3 1267.365 MHz 145.880 MHz
Departing 4 1267.370 MHz 145.880 MHz
Departing 5 1267.375 MHz 145.880 MHz
Loss of Signal (LOS) 1267.380 MHz 145.880 MHz

AMSAT Rover Award Photo Contest

AMSAT’s Director of Contests and Awards Bruce Paige, KK5DO, solicited photos to be used on the certificate for the new AMSAT Rover Award. The four finalists are listed below. Please select your favorite. The top vote receiver will be used on the award certificate. Deadline to vote is January 29, 2018 at 23:59:59 UTC.

 

Photo 1

 

Photo 2

 

Photo 3

 

Photo 4

Which photo should be used on the AMSAT Rover Award certificate?