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searchwing-wifibroadcast [2020/04/16 10:52] wf68spef |
searchwing-wifibroadcast [2021/04/19 13:03] (current) swrm [Mavlink-Transport] |
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| There are various projects that use the WiFi broadcast code: | There are various projects that use the WiFi broadcast code: | ||
| + | * [[https://github.com/svpcom/wifibroadcast | svpcoms wifibroadcast]] most promising implementation feature wise | ||
| + | * [[https://github.com/booo/openwrt-wifibroadcast | OpenWRT package for wifibroadcast and a custom implementation of wifibroadcast]] | ||
| * [[https://github.com/rodizio1/EZ-WifiBroadcast|EZ-WifiBroadcast]] | * [[https://github.com/rodizio1/EZ-WifiBroadcast|EZ-WifiBroadcast]] | ||
| * [[https://github.com/OpenHD/Open.HD|Open.HD]] | * [[https://github.com/OpenHD/Open.HD|Open.HD]] | ||
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| The code for injecting packets is quite simple and can be adapted to our needs, e.g. improved forward error correction. | The code for injecting packets is quite simple and can be adapted to our needs, e.g. improved forward error correction. | ||
| + | ===== Ath9k ===== | ||
| + | |||
| + | The code should work with all drivers that provide a monitor mode to inject packets. We tested the code on a Atheros AR9280 Rev:2 mini-pci card. Setting the bitrate with iw: | ||
| + | |||
| + | iw wlan0 set bitrates legacy-2.4 5 | ||
| + | |||
| + | Result was an injection rate of around 12 MBit/s in the nosy Berlin environment. | ||
| + | |||
| + | **We don't need a patched kernel to set the bitrate!** | ||
| + | |||
| + | [[https://wireless.wiki.kernel.org/en/users/Drivers/ath10k/debug#manual_bitrates_configuration|Manual bitrate configuration for ath9k/10k]] | ||
| + | |||
| + | ===== Mavlink-Transport ===== | ||
| + | |||
| + | * optional: Simulate FC-MAVLink-Data on PC - using Ardupilot SITL on UART output: | ||
| + | |||
| + | see [[https://www.hs-augsburg.de/homes/beckmanf/dokuwiki/doku.php?id=multicamera_pixracer_connection#sitl_computer_simulated_pixracer_pi4|SITL]] | ||
| + | |||
| + | * Pi Sender: Send data via wifibroadcast from Serial input port data - Mavlink Data from FC | ||
| + | |||
| + | configure UART using for 9600 Baudrate (or checkout your telemetry for correct Baud): | ||
| + | |||
| + | ''stty -F /dev/ttyAMA0 9600'' | ||
| + | |||
| + | Send data: | ||
| + | |||
| + | ''./tx wlan0 < /dev/ttyAMA0'' | ||
| + | |||
| + | * Groundstation station receiver side: Receive wifibroadcast data and pipe into QGC: | ||
| + | |||
| + | ''sudo ./rx wlp0s29u1u2 2> /dev/null | nc -l 5000'' | ||
| + | |||
| + | * QGC: New connection with TCP on Port 5000 - receives telemetry | ||
| + | |||
| + | source tx and rx commands: https://github.com/booo/wifibroadcast/ ? | ||
| + | |||
| + | ==== Mavlink Routing ==== | ||
| + | |||
| + | Captured data needs to be sent from companion (connected to fc) to gcs. | ||
| + | On the companion there might be also ROS needing access to mavlink messages. | ||
| + | |||
| + | On the gcs side the sent data needs to be handled. QGroundControl can't handle that captured data -> needs additional software. | ||
| + | |||
| + | Routing of pakets (ros|captured data processing)<*>companion<->fc<->radio<->gcs<*>(qgroundcontrol|captured data processing) | ||
| + | |||
| + | - <*> routing to multiple endpoints | ||
| + | |||
| + | - radio is long distance rfd868 or similar | ||
| + | |||
| + | |||
| + | Parallel to the radio connection there might be a long distance wifi connection. | ||
| + | |||
| + | (images|captured data processing)<*>companion<->wifi<->gcs<*>(qgroundcontrol?|captured data processing) | ||
| + | |||
| + | open question: route (encapsulated) mavlink pakets also over wifi? | ||
| + | |||
| + | depending on that: combine of images / captured data on gcs side - how? | ||
| + | |||
| + | |||
| + | ==== Captured Data Workflow ==== | ||
| + | |||
| + | TBD. | ||
| ===== Tests ===== | ===== Tests ===== | ||
| - | * 20MBit/s in the basement in Neukölln, distance 50cm, two omni antennas with unknown dBiÌý | + | * 20MBit/s in the basement in Neukölln, distance 50cm, two omni antennas with unknown dBiÌý |
| - | * 4MBit/s on Tempelhofer Feld, distance ~ 200m, unpatched kernel, txpower maybe not at max, both sides small omni antennas with unknown dBi | + | * 4MBit/s on Tempelhofer Feld, distance ~ 200m, unpatched kernel, txpower maybe not at max, both sides small omni antennas with unknown dBiÌý |
| + | * unkown MBit/s, max. distance ~ 1km, esp 201 with 1-3dBi omni, ground station Nanostation M2, unknown tx power on both sides, normal wifi, no wifibroadcastingÌý | ||
| + | * [[https://www.hs-augsburg.de/homes/beckmanf/dokuwiki/doku.php?id=searchwing-flug-107 | Testflight with 8XX MHz]] | ||
| ===== TODO ===== | ===== TODO ===== | ||