XML schema

An area to discuss the design and development of a system to maintain information on satellites and their characteristics

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Re: XML schema

Postby pa3weg » Wed Apr 29, 2015 10:31 am

pa9tv wrote:* frequency should be in Hz.
* how about centerfreq, bandwidth instead of upper/lower bounds.


I agree with the CF / BW combination, and this is also how we are building the IARU database at the moment.
Frequencies are ALWAYS in Hz in any formal communication with ITU, so indeed that should always be the case.
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Re: XML schema

Postby pa9tv » Wed Apr 29, 2015 12:17 pm

Last result:
Code: Select all
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<response version="v1">
    <satellite id="sat0">
        <name>Oscar 7</name>
        <alias>AO-7</alias>
        <catalog-number>74089B</catalog-number>
        <international-designator>1974-089-B</international-designator>
        <transponder>
            <bandwidth>100000</bandwidth>
            <rxfrequency>145900000</rxfrequency>
            <txfrequency>29450000</txfrequency>
            <inverting>false</inverting>
        </transponder>
        <transponder>
            <bandwidth>50000</bandwidth>
            <rxfrequency>432150000</rxfrequency>
            <txfrequency>145950000</txfrequency>
            <inverting>true</inverting>
            <confirmation>
                <callsign>OZ1MY</callsign>
                <time>2015-04-29 00:46:00</time>
            </confirmation>
        </transponder>
        <beacon>
            <frequency>2304100000</frequency>
            <status>inactive</status>
        </beacon>
        <telemetry>
            <frequency>29502000</frequency>
            <modulation>CW</modulation>
        </telemetry>
        <telemetry>
            <frequency>145977500</frequency>
            <description>Mode U/V (B) TLM Beacon</description>
            <modulation>CW</modulation>
        </telemetry>
        <telemetry>
            <frequency>435100000</frequency>
            <description>Mode U TLM Beacon</description>
            <modulation>FSK</modulation>
        </telemetry>
        <owner>http://www.amsat.org/?page_id=1031</owner>
        <phase>ORBIT</phase>
    </satellite>
    <satellite id="sat1">
        <name>UWE-3</name>
        <catalog-number>39446</catalog-number>
        <phase>ORBIT</phase>
    </satellite>
    <satellite id="sat2">
        <name>FUNcube-3</name>
        <alias>EO79</alias>
        <launch-date>2014-06-19</launch-date>
        <phase>ORBIT</phase>
    </satellite>
    <satellite id="sat3">
        <name>AMSAT Phase 3C</name>
        <alias>P3C</alias>
        <alias>AO-13</alias>
        <phase>DECEASED</phase>
    </satellite>
    <satellite id="sat4">
        <name>AMSAT Phase 3E</name>
        <alias>P3E</alias>
        <image>https://www.p3e-satellite.org/en_EN/images/p3e_09.jpg</image>
        <logo>https://www.p3e-satellite.org/en_EN/images/p3e_logo.jpg</logo>
        <phase>PRELAUNCH</phase>
    </satellite>
    <satellite id="sat5">
        <name>ARISS</name>
        <alias>ISS</alias>
        <alias>Zarya</alias>
        <catalog-number>25544</catalog-number>
        <international-designator>1998-067A</international-designator>
        <image>http://nssdc.gsfc.nasa.gov/image/spacecraft/iss.jpg</image>
        <phase>ORBIT</phase>
    </satellite>
    <satellite id="sat6">
        <name>Delfi C3</name>
        <alias>DO-64</alias>
        <catalog-number>32789</catalog-number>
        <international-designator>2008-021G</international-designator>
        <beacon>
            <frequency>145870000</frequency>
            <status>inactive</status>
        </beacon>
        <telemetry>
            <frequency>145870000</frequency>
            <description>Telemetry beacon</description>
            <modulation>BPSK</modulation>
            <symbol-rate>1200</symbol-rate>
            <protocol>AX25</protocol>
        </telemetry>
        <phase>ORBIT</phase>
        <qsl-contact>
            <email>Delfi@TUdelft.nl</email>
        </qsl-contact>
    </satellite>
    <satellite id="sat7">
        <name>FUNcube-1</name>
        <alias>AO73</alias>
        <alias>AO-73</alias>
        <telemetry>
            <frequency>145935000</frequency>
            <description>Telemetry beacon</description>
            <modulation>BPSK</modulation>
            <symbol-rate>1200</symbol-rate>
        </telemetry>
        <phase>ORBIT</phase>
        <datawebsite>http://warehouse.funcube.org.uk/</datawebsite>
    </satellite>
</response>


I have supporting java classes with jaxb annotations.
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Re: XML schema

Postby g4dpz » Mon May 04, 2015 9:39 am

Hi,

A few observations:

A satellite may have more than one alias, depending in the source: AMSAT / Celestrak

Should telemetry be a child of beacon

73

- Dave
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Re: XML schema

Postby pa9tv » Mon May 04, 2015 10:05 am

g4dpz wrote:A satellite may have more than one alias, depending in the source: AMSAT / Celestrak

I agree, if only to catch dominant spelling variants. or ISS/Zarya case.

g4dpz wrote:Should telemetry be a child of beacon


True, you can view telemetry as a specialization of a beacon. In any case, if they share properties, these should be equally named.
I would not make it a child element in the xml, because i cant see any physical dependency other than the satellite.
Telemetry can be used as a beacon in a rf listeners case, i agree.
How would you differentiate between a CW beacon only and a telemetry-beacon only situation.
In a client it would require testing for the existence of properties of the beacon, or adding an extra element 'beacon-implementation' which existence can be tested.

In the underlying object model you could make telemetry a derivation of beacon, but how do you model a transponder into this. If you want this to drive your receiver, the objects could all implement an interface with freq, mode, bw. But this will be up to the implementors of the clients. If you do it in java, it would be my preferered approach.

Code: Select all
   <satellite id="sat3">
        <name>AMSAT Phase 3C</name>
        <alias>P3C</alias>
        <alias>AO-13</alias>
        <phase>DECEASED</phase>
    </satellite>
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Re: XML schema

Postby pa9tv » Mon May 04, 2015 10:19 am

Reading the topic about WX sats, it would be meaningful to include the type of data that is sent if we model WX data as telemetry.
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Re: XML schema

Postby pa9tv » Mon May 04, 2015 12:15 pm

Modelling issue APT.

AM subcarrier, modulated with FM.

multiple approaches:
- fixed modulation types AM, FM, APT, etc. which need additions on new modulation forms.
- describe the first detector, and optional the second.
- free field to describe popular name of modulation.
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Re: XML schema

Postby pa9tv » Mon May 04, 2015 12:35 pm

Code: Select all
    <satellite id="sat8">
        <name>NOAA 15</name>
        <alias>Advanced TIROS-N (ATN)</alias>
        <catalog-number>25338</catalog-number>
        <international-designator>1998-030A</international-designator>
        <telemetry>
            <frequency>137620000</frequency>
            <description>APT picture transmissions</description>
            <modulation>FM</modulation>
            <modulation-name>APT</modulation-name>
        </telemetry>
        <telemetry>
            <frequency>137350000</frequency>
            <description>POES Direct Sounder Broadcast, charged particle spectrometer</description>
            <modulation>PSK</modulation>
            <modulation-name>TIP Digital split phase 67deg</modulation-name>
            <symbol-rate>8320</symbol-rate>
        </telemetry>
        <phase>ORBIT</phase>
    </satellite>
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Re: XML schema

Postby g4dpz » Mon May 04, 2015 2:37 pm

I should prefer the catalogue number to be the primary key.
Java Long, MySQL bigint(20) and standard for Hibernate/JPA @id
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Re: XML schema

Postby pa9tv » Mon May 04, 2015 2:39 pm

g4dpz wrote:I should prefer the catalogue number to be the primary key.
Java Long, MySQL bigint(20) and standard for Hibernate/JPA @id


Are there any satellites without a satcat number? If none, indeed a good primary key.
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