[aprssig] APRS USER TELEMETRY Plan for ANDE and RAFT

Robert Bruninga bruninga at usna.edu
Tue Dec 19 17:49:34 CST 2006

ANDE, RAFT and MARScom Telemetry Plan:

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

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reference) it is obsolete the moment you view it.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

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.  


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

For more info on telemetry, check these pages:  

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


Bob Bruninga, WB4APR
US Naval Academy Satellite Lab

> -----Original Message-----
> From: aprssig-bounces at lists.tapr.org 
> [mailto:aprssig-bounces at lists.tapr.org] On Behalf Of Robert
> Sent: Monday, December 18, 2006 6:58 PM
> To: aprssig at lists.tapr.org
> Subject: [aprssig] APRS USER Operations Plan for ANDE and RAFT
> RAFT and ANDE are APRS satellites to be deployed on Thursday.
> We ask that ALL radio amateurs (except for command stations)
> refrain from any transmissions until after the spacecraft have
> been opened for general use.  There are many stations involved
> in the checkout, so wait until you see specific authorization
> for general use before using the digipeater.  If all goes well
> in a few days, we hope to open the satellites up for general
> in accordance with the User Service Agreement.  See:
> http://www.ew.usna.edu/~bruninga/ande/ANDEcontract.txt
> The success of these digipeaters is protocol driven and
> on user adherence to published operating parameters.  Please
> check the User Service Agreement before operating and
> periodically throughout the short life of these satellites.
> Basically it says you are authorized for these initial beacon
> rates:
> Unattended, beacon one APRS packet per 5 minutes only
> Attended Base, beacon one Position packet per 2 minutes
> Mobile, beacon no higher than 2 minutes
> Attended 5W HT, is authorized to beacon at a 1 minute rate.
> To aid everyone in understanding the statistics of this
> please include your Effective Radiated Power (ERP) and beacon
> rate in your packet.  Example:
> mobile.
> Remember that ERP is your TX power plus your antenna system
> gain.
> Operating authorization will change as we learn the demands on
> the uplink and the load on the systems.  Keep up to date on
> page that covers all three satellites (ANDE, RAFT and NMARS).
> See:
> http://www.ew.usna.edu/~bruninga/ande-raft-ops.html
> All of these new satellites have less than optimum antennas
> so they will probably be harder to operate than PCSAT-1.  We
> hope that PCSAT-1 will come out of hybernation the first week
> January for some multi-satellite opportunities.  Stay tuned.
> Bob Bruninga, WB4APR
> USNA Satellite Lab
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