Follow PicSat on
   Twitter30width    Youtube30width
French version   English version    
Logo transparent
Unravelling the Beta Pictoris System
Picsat is: in a polar orbit at 505km altitude
Number of telemetry packets received today:
Last beacon satellite:
2018-03-17 21:34:38 UTC

Last beacon payload:
2018-03-17 21:34:41 UTC

Uplink is not active
Downlink is not active

PicSat Simple Downlink Share (SiDS) Interface

About SiDS

The SiDS (Simple Downlink Share) interface is a simple and straightforward standard which can be used to allow any receving station to forward data packets to a mission control center located elsewhere on the globe. It was introduced and first used by the University of W├╝rzburg, for the UWE-3 mission. The whole standard is documented in this PDF. To make life easier for the radio-amateurs wishing to contribute to the PicSat mission, and in the hope of reinforcing even more this collaboration, we decided to implement a Web server complying with this amateur standard.

The PicSat SiDS interface

Identification and security of the SiDS system

In its specification, the SiDS system does not really include any way to properly authenticate the user when sending the data. It relies mainly on the honesty of the users.

In the PicSat SiDS system, the "source" of the request (see parameter list below) is checked against the list of users registered on this Website. So if you want to send us your received data frames via the SiDS system, you must first create an account on the website. If you have a callsign, you should use it as the "source" parameter in your requests. If you do not have a callsign, you may use your username instead.

When you register on the website, you will have the possibility to open/close your SiDS access on your profile page. By default, the access if closed, so you must first open it before sending data. If you close your access, any request sent using your username/callsign will be rejected by the server.

Again, the callsign/username is used to allocate the packet to the user, and there is no way for us to authenticate the user. Keep that in mind when opening your SiDS access!

Addressing a request

The base address of the server is the following:
SiDS requests are sent as HTTP POST requests to this base address, with all the required and optional parameters: DC BA 98 76 54 32 10&locator=latlong&longitude=5E&latitude=45N
The required and optional parameters are described in the SiDS standard (see downloadable PDF in the above section), reproduced below for the reader's convenience.

A complete list of possible parameters for a PicSat SiDS request is given in the table below.
Parameter Required Type Description Example
noradID True int Norad ID of the spacecraft 43131
source True str Callsign or user name of the receiver F4HZG, or Mathias Nowak
timestamp True str UTC timestamp (see ISO 8601) 2018-01-24T23:42:46Z
frame True str The received data, in hexadecimal string (AX.25 packet with or without KISS 'C0 00 .. C0'. Whitespaces optional. C0 00 A9 05 DE ...
locator True str Type of the given receiver's location. Currently, only 'longLat' is supported. longLat
longitude True str Longitude of the receiver (WGS84) 8.95564E
latitude True str Latitude of the receiver (WGS84) 49.73145N
tncPort False int Optional as per SiDS standard specification, but not used in PicSat SiDS system 0
azimuth False float azimuth degree of directionnal antenna (if avaiblable) 10.5
elevation False float elevation degree of directionnal antenna (if avaiblable) 85.0
fDown False float Frequency of the receiver's downlink channel during reception (with Doppler), in Hz 435525000
Server Response

Upon reception of a request, the SiDS server replies to the user to let him know if the request was successful: