ground with our 10mW units and over 100k feet AGL with
the 40mW devices.
- === APRS
-
- TeleGPS 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. You
- can configure the APRS interval; that
- process is described in the Configure TeleGPS
- section of the TeleGPS Application chapter.
-
- 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.
-
- 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.
-
- .TeleGPS APRS Comments
- [options="header",cols="1,1,3"]
- |====
- |Field |Example |Description
-
- |1
- |L
- |GPS Status U for unlocked, L for locked
-
- |2
- |6
- |Number of Satellites in View
-
- |3
- |B4.0
- |Altimeter Battery Voltage
-
- |4
- |1286
- |Device Serial Number
- |====
-
- Here's an example of an APRS comment showing GPS lock with 6
- satellites in view and a battery at 4.0V from device 1286.
-
- ....
- L6 B4.0 1286
- ....
-
- Make sure your battery is above 3.8V 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.
-
- 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.
+ :aprsdevices: TeleGPS
+ :configure_section: _configure_device
+ include::aprs-operation.raw[]
=== Configurable Parameters
Configuring TeleGPS is very
simple; the few configurable parameters can all be set
using the TeleGPS application over USB. Read
- the Configure TeleGPS section in the TeleGPS Software chapter below
- for more information.
-
- ==== Radio Frequency
-
- Altus Metrum boards support radio frequencies in the 70cm
- band. By default, the configuration interface provides a
- list of 10 “standard” frequencies in 100kHz channels starting at
- 434.550MHz. However, the firmware supports use of
- any 50kHz multiple within the 70cm band. At any given
- launch, we highly recommend coordinating when and by whom each
- frequency will be used to avoid interference. And of course, both
- TeleGPS and the receiver must be configured to the same
- frequency to successfully communicate with each other.
-
- ==== Callsign
-
- This sets the callsign used for telemetry and APRS to
- identify the device.
-
- ==== Telemetry/RDF/APRS Enable
-
- You can completely disable the radio, if necessary, leaving
- TeleGPS only logging data to internal memory.
-
- ==== APRS Interval
-
- 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.
-
- ==== Maximum Flight Log
-
- Changing this value will set the maximum amount of flight
- log storage that an individual flight will use. The
- available storage is divided into as many flights of the
- specified size as can fit in the available space. You can
- download and erase individual flight logs. If you fill up
- the available storage, future flights will not get logged
- until you erase some of the stored ones.
-
- ==== Logging Trigger Motion
-
- If TeleGPS moves less than this distance over a long period
- of time, it will not log that location, saving storage space.
-
- ==== Position Reporting Interval
-
- This sets how often TeleGPS reports position information via
- telemetry and to the on-board log. Reducing this value will
- save power and logging memory consumption.
+ the Configure TeleGPS section in the TeleGPS Software chapter
projects / fw / altos / blobdiff