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diff --git a/doc/altusmetrum.xsl b/doc/altusmetrum.xsl index 60ad118a..fb08f5c6 100644 --- a/doc/altusmetrum.xsl +++ b/doc/altusmetrum.xsl @@ -2009,22 +2009,112 @@ NAR #88757, TRA #12200 time, and would of course appreciate customer feedback on performance in higher altitude flights! </para> + </section> + <section> + <title>APRS</title> <para> TeleMetrum v2.0 and TeleMega can send APRS if desired, and the interval between APRS packets can be configured. As each APRS packet takes a full second to transmit, we recommend an interval of at least 5 seconds to avoid consuming too much - battery power or radio channel bandwidth. + battery power or radio channel bandwidth. You can configure + the APRS interval using AltosUI; that process is described in + the Configure Altimeter section of the AltosUI chapter. + </para> + <para> + AltOS uses the APRS compressed position report data format, + which provides for higher position precision and shorter + packets than the original APRS format. It also includes + altitude data, which is invaluable when tracking rockets. We + haven't found a receiver which doesn't handle compressed + positions, but it's just possible that you have one, so if you + have an older device that can receive the raw packets but + isn't displaying position information, it's possible that this + is the cause. + </para> + <para> + The APRS packet format includes a comment field that can have + arbitrary text in it. AltOS uses this to send status + information about the flight computer. It sends four fields as + shown in the following table. + </para> + <table frame='all'> + <title>Altus Metrum APRS Comments</title> + <?dbfo keep-together="always"?> + <tgroup cols='3' align='center' colsep='1' rowsep='1'> + <colspec align='center' colwidth='*' colname='Field'/> + <colspec align='center' colwidth='*' colname='Example'/> + <colspec align='center' colwidth='4*' colname='Description'/> + <thead> + <row> + <entry align='center'>Field</entry> + <entry align='center'>Example</entry> + <entry align='center'>Description</entry> + </row> + </thead> + <tbody> + <row> + <entry>1</entry> + <entry>L</entry> + <entry>GPS Status U for unlocked, L for locked</entry> + </row> + <row> + <entry>2</entry> + <entry>6</entry> + <entry>Number of Satellites in View</entry> + </row> + <row> + <entry>3</entry> + <entry>B4.0</entry> + <entry>Altimeter Battery Voltage</entry> + </row> + <row> + <entry>4</entry> + <entry>A3.7</entry> + <entry>Apogee Igniter Voltage</entry> + </row> + <row> + <entry>5</entry> + <entry>M3.7</entry> + <entry>Main Igniter Voltage</entry> + </row> + </tbody> + </tgroup> + </table> + <para> + Here's an example of an APRS comment showing GPS lock with 6 + satellites in view, a primary battery at 4.0V, and + apogee and main igniters both at 3.7V. + <screen> + L6 B4.0 A3.7 M3.7 + </screen> + </para> + <para> + Make sure your primary battery is above 3.8V, any connected + igniters are above 3.5V and GPS is locked with at least 5 or 6 + satellites in view before flying. If GPS is switching between + L and U regularly, then it doesn't have a good lock and you + should wait until it becomes stable. + </para> + <para> + If the GPS receiver loses lock, the APRS data transmitted will + contain the last position for which GPS lock was + available. You can tell that this has happened by noticing + that the GPS status character switches from 'L' to 'U'. Before + GPS has locked, APRS will transmit zero for latitude, + longitude and altitude. </para> </section> <section> <title>Configurable Parameters</title> <para> Configuring an Altus Metrum altimeter for flight is very - simple. Even on our baro-only TeleMini and EasyMini boards, the use of a Kalman - filter means there is no need to set a “mach delay”. The few - configurable parameters can all be set using AltosUI over USB or - or radio link via TeleDongle. + simple. Even on our baro-only TeleMini and EasyMini boards, + the use of a Kalman filter means there is no need to set a + “mach delay”. The few configurable parameters can all be set + using AltosUI over USB or or radio link via TeleDongle. Read + the Configure Altimeter section in the AltosUI chapter below + for more information. </para> <section> <title>Radio Frequency</title> @@ -2041,6 +2131,35 @@ NAR #88757, TRA #12200 </para> </section> <section> + <title>Callsign</title> + <para> + This sets the callsign used for telemetry, APRS and the + packet link. For telemetry and APRS, this is used to + identify the device. For the packet link, the callsign must + match that configured in AltosUI or the link will not + work. This is to prevent accidental configuration of another + Altus Metrum flight computer operating on the same frequency nearby. + </para> + </section> + <section> + <title>Telemetry/RDF/APRS Enable</title> + <para> + You can completely disable the radio while in flight, if + necessary. This doesn't disable the packet link in idle + mode. + </para> + </section> + <section> + <title>APRS Interval</title> + <para> + This selects how often APRS packets are transmitted. Set + this to zero to disable APRS without also disabling the + regular telemetry and RDF transmissions. As APRS takes a + full second to transmit a single position report, we + recommend sending packets no more than once every 5 seconds. + </para> + </section> + <section> <title>Apogee Delay</title> <para> Apogee delay is the number of seconds after the altimeter detects flight |