Telemetry plan for ANDE and RAFT amateur radio satellites

The first few days of ANDE, RAFT and MARScom will focus on
capturing whole orbit telemetry. User packets are not
authorized (except for authorized command station checkouts).

But we do welcome TELEMETRY and LOG capture files for any data that did not make it through the Satgates and APRS Internet System.

We make these telemetry requests:

1) Make sure your TNC or logging clock is within a second or so of UTC time. It can be LOCAL time if you clearly tell us
whether to ADD or SUBTRACT X hours from the time indicated. If you send us the file, include your statment of the accuracy or offset of your clock in the first line of the file.

2) Please compare your packets to the raw packets captured at the bottom of the live FINDU downlink page:
http://pcsat.aprs.org . We only need a copy of the raw packets that you captured that are not on that list (at the bottom of the page). You will have to make your comparison within an hour or so, depending on activity, so that the packets of interest do not scroll off the page.

3) It would be very helpful to our data team if you edited out all the dupes and only send us the packets that are not on FINDU.

CAUTION: Since the FINDU page normally does not have a time stamp and only shows the relative age of a packet (but no reference) it is obsolete the moment you view it. So it is best to either annotate the time at the instant that you refreshed the page, or better is to click on the LINK that says "clickhere to see times in UTC". It will download another page with complete time stamps.

FREQUENCY: Monitor 145.825 MHz 1200 baud packet for ANDE and RAFT. Monitor 27.965 SSB 1200 baud AFSK packet for NMARS.

Notice, you may also hear UO-11 on the same 145.825 frequency. NMARS is lighter and will eventually lead RAFT.

TELEMETRY NOTES: The telemetry from all three satellites are in standard APRS telemetry format of the KPC-3 TNC's:
T#SSS,111,222,333,444,555,11111111,000. There are several easy observations:

1) It is important to note that T#SSS is a serial number and
that these serial numbers are helpful for determining dupes or absolute time. For RAFT and NMARS, these are once a minute and will count up to 999 and then roll back to 000. That takes about 16 hours unless we take some high rate data.

2) ANDE, however, does a COLD boot on every pass. So for ANDE, the T#SSS is every 50 seconds and will tell you how long the TNC has been up since it last awoke. Hopefully it will only be awake for 10 to 20 minutes at a time, though while it is in range of the pesky RAFT's telemetry, it may be kept awake for hours until RAFT gets out of range.

WHAT TO LOOK FOR:
For RAFT and NMARS you can visually decode the 5 channels of telemetry (see format above).
111 - is Voltage in 0.1 volts. (80 ==> 8.0 volts)
222 - is Solar current in 2 mA's. Multiply by 2 for mA
333 - is Battery current in 2 mA's. Multiply by 2 for mA
444 - is Load current in 2 mA's. Multiply by 2 for mA
555 - is temperature (a cubic, but 128 is about room temp)

A healthy spacecraft will be above 8.0 volts and will see
consistent solar current while in the sun.

ANDE is more complicated because it has a total of 20 telemetry channels divided up among four separate packets. So it takes 3.3 minutes to get a complete set. You can tell which set you get by the first 2 digits of the 8 bit number at the end. 00XXXXXX, 01XXXXXX, 10XXXXXX and 11XXXXXX.

ANDE runs on primary batteries and no solar power, so it either works or it doesn't. But the most important data is the spin rate which we hope to derive from the 6 solar sensors. These packets are the 11XXXXXX packets.

For more info on telemetry, check these pages:
http://www.ew.usna.edu/~bruninga/craft/RAFTeqns.gif
http://www.ew.usna.edu/~bruninga/ande/ANDEeqns.txt

And for up-to-date info about this mission, please check the
main operations page:

http://www.ew.usna.edu/~bruninga/ande-raft-ops.html

Bob Bruninga, WB4APR
US Naval Academy Satellite Lab

Frequencies:
ANDE Side A: 145.825 MHz Digipeater up/downlink 1200 baud packet
ANDE Side B: 145.825 MHz downlink (backup to side A only)
RAFT System: 145.825 Mhz Digipeater up/downlink 1200 baud packet
RAFT PSK-31: 28.120 MHz HF PSK-31 uplink -downlink on 145.825 MHz

See also
http://www.southgatearc.org/news/december2006/
satellites_to_deploy_thursday.htm

http://www.southgatearc.org/news/december2006/
satellite_deployment.htm

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