Overview

If you ever wanted to setup a Raspberry Pi as a ADSB, Stratum 1 and network server, you've come to the right place. We'll run you through what hardware and software you'll need and how to set it up.

Hardware
Software
Hardware Setup
Software Installation
|- Pi Installation
|- Pi Setup
|- Tools Installation
|- Dump1090
Configuration

/boot/firmware/cmdline.txt

/boot/firmware/config.txt

/etc/modules

/etc/network/interfaces

/etc/default/gpsd

/etc/systemd/system/gpsd.socket

/lib/systemd/system/gpsd.socket

/etc/default/dnsmasq

/etc/dnsmasq/dnsmasq.conf

/etc/default/ntpsec

/etc/ntpsec/ntp.conf

/etc/default/hostapd

/etc/hostpad/hostpad.conf

/etc/default/shorewall

/etc/shorewall/shorewall.conf

/etc/shorewall/*

Reboot
Testing

Starting the services

Pulse Per Second

Global Positioning System

Testing Dump1090

Enable the services

Conclusion

The Hardware

You'll need ...

The Software

You'll install ...

Raspbian OS
gpsmon Location and Time
hostapd Wifi Access Point
dnsmasq DHCP and DNS Server ( Network services)
ntpsec NTP Server ( Stratum 1)
shorewall Firewall / Router

Hardware Setup

The most important part of the setup is wirring the GPS board to the Raspberry Pi. The following diagram shows the pinout.

---------------------          -------------
| Pi Zero           |          | GPS Board |
|-------------------|          |-----------|
| Pin 2  5V Power   |          |           |
| Pin 4  5V Power   |<-------->| VCC       |
| Pin 6  Ground     |<-------->| GND       |
| Pin 8  GPIO 14 TX |<-------->| RX        |
| Pin 10 GPIO 15 RX |<-------->| TX        |
| Pin 12 GPIO 18    |<-------->| PPS       |
---------------------          -------------

Software Installation

Raspberry Pi

The first thing you'll need to do is install the latest version of Raspbian OS. We would recommend using the Raspberry Pi Imager to do this but we prefer to download the image and "dd" it across with

dd of=/dev/sd? if=2024-03-15-raspios-bookworm-arm64-full.img bs=4M status=progress

Raspberry Setup

Once the Pi OS has been installed, booted and localised you'll need to choose some basic raspi-config options.

Interfaces -> SSH -> Would you like the SSH server to be enabled -> Yes
Interfaces -> Serial Port -> Login shell over serail -> No
Interfaces -> Serial Port -> Serial port hardware to be enabled -> Yes
Advanced Options -> Network Interface Names -> Enable predictable network interface names -> Yes
Finish -> Reboot -> Yes

Tools

Now we need to install some tools. Here's the commands you'll need to run.

sudo apt update
sudo apt upgrade
sudo apt install vim gpsd gpsd-clients hostapd dnsmasq ntpsec shorewall git build-essential cmake libusb-1.0-0-dev librtlsdr-dev librtlsdr0 rtl-sdr pipenv

This will be a good to time to reboot incase the upgrade or update needs to relaod something

sudo reboot

Dump1090

To install dump1090, the ADSB decoder, you will need to ...

sudo apt install librtlsdr-dev
git clone https://github.com/antirez/dump1090.git
cd dump1090
make

To start dump1090 at boot and the following line to /etc/rc.local ...

cd /home/pi/dump1090/ && ./dump1090 --net 2>/dev/null 1>&2 &

The Configuration

The configuration is the tricky part but the following steps should get you up and running. Note that you will need to use an editor such as nano or vi to edit these files and nano would be the preferred choice but vim is a better option. To use vim you will have to install it with sudo apt install vim

/boot/firmware/cmdline.txt

Add the following option to to the kernel boot options in the /boot/firmware/cmdline.txt

bcm2708.pps_gpio_pin=18

/boot/firmware/config.txt

Add the following options to the /boot/firmware/config.txt

enable_uart=1
dtoverlay=pi3-disable-bt-overlay
dtoverlay=pi3-miniuart-bt
dtoverlay=disable-bt
dtoverlay=pps-gpio,gpiopin=18

/etc/modules

Add the following module to the /etc/modules

pps-gpio

/etc/network/interfaces

Ues the following config for //etc/network/interfaces

# interfaces(5) file used by ifup(8) and ifdown(8)
# Include files from /etc/network/interfaces.d:
source /etc/network/interfaces.d/*

auto eth0
allow-hotplug eth0
iface eth0 inet dhcp

# Setup static address for the Hostapd
auto wlan0
allow-hotplug wlan0
iface wlan0 inet static
address 10.10.17.1
netmask 255.255.255.0

/etc/default/gpsd

Use the following configuration for /etc/default/gpsd

DEVICES="/dev/ttyAMA0 /dev/pps0"
GPSD_SOCKET="/var/run/gpsd.sock"
GPSD_OPTIONS="-n -G -r -b"
START_DAEMON="true"
USBAUTO="true"

/etc/systemd/system/gpsd.socket

Use the following configuration for /etc/systemd/system/gpsd.socket

[Unit]
Description=GPS (Global Positioning System) Daemon Sockets

[Socket]

#ListenStream=
ListenStream=/var/run/gpsd.sock
ListenStream=[::1]:2947
ListenStream=0.0.0.0:2947

## To allow gpsd remote access, start gpsd with the -G option and
## uncomment the next two lines:
##ListenStream=[::]:2947
SocketMode=0600
# BindIPv6Only=no


[Install]
WantedBy=sockets.target

/lib/systemd/system/gpsd.socket

Use the following configuration for /lib/systemd/system/gpsd.socket

[Unit]
Description=GPS (Global Positioning System) Daemon Sockets

[Socket]
ListenStream=/run/gpsd.sock
ListenStream=[::1]:2947
ListenStream=127.0.0.1:2947
## To allow gpsd remote access, start gpsd with the -G option and
## uncomment the next two lines:
##ListenStream=[::]:2947
SocketMode=0600
BindIPv6Only=yes


[Install]
WantedBy=sockets.target

/etc/default/dnsmasq

Nothing to change in /etc/default/dnsmasq

/etc/dnsmasq/dnsmasq.conf

Here is a working example of/etc/dnsmasq/dnsmasq.conf. Note the IP address as this is used in the network configuration and the hostapd configuration.

listen-address=127.0.0.1,10.10.17.1
resolv-file=/etc/resolv.conf
dhcp-authoritative
except-interface=eth0
interface=wlan0
addn-hosts=/etc/hosts
bind-interfaces
domain-needed
bogus-priv
expand-hosts
domain=gpsant
local=/.gpsant/
cache-size=1000
dhcp-range=lan,10.10.17.2,10.10.17.254,2h
dhcp-option=lan,121,10.10.17.0/24,10.10.17.1
dhcp-option=lan,option:ntp-server,10.10.17.1

/etc/default/ntpsec

Use the following configuration for /etc/default/ntpsec

NTPD_OPTS="-g"
IGNORE_DHCP="yes"
NTPSEC_CERTBOT_CERT_NAME=""

/etc/ntpsec/ntp.conf

Use the following configuration for /etc/ntpsec/ntp.conf

driftfile /var/lib/ntpsec/ntp.drift
leapfile /usr/share/zoneinfo/leap-seconds.list
refclock shm unit 1 refid PPS0
refclock shm unit 0 refid GPS0
server 127.127.22.0 minpoll 4 maxpoll 4 iburst
fudge 127.127.22.0 refid PPS0
restrict -4 default kod nomodify limited
restrict 192.168.0.0/8
restrict 10.10.0.0/8
restrict 127.0.0.1
restrict ::1

/etc/default/hostapd

Use the following configuration for /etc/default/hostapd

DAEMON_OPTS="-T -i wlan0"

/etc/hostapd/hostpad.conf

Use the following configuration for /etc/hostapd/hostpad.conf

hw_mode=g
channel=6
ieee80211d=1
country_code=GB
ieee80211n=1
wmm_enabled=1
driver=nl80211
ssid="YOUR_SSID_NAME"
auth_algs=1
wpa=2
wpa_passphrase="YOUR_SSID_PASSWORD"
ignore_broadcast_ssid=0  # 0 = visible, 1 = hidden
wpa_key_mgmt=WPA-PSK  
rsn_pairwise=CCMP

/etc/default/shorewall

Configuring shorewall has the potential to lock you out of SSH access so be careful or at least have direct access with a keyboard and screen.

startup=1

/etc/shorewall/shorewall.conf

Change the following option in /etc/shorewall/shorewall.conf so shorewall will start

STARTUP_ENABLED=Yes

/etc/shorewall/*

The following configuration files need adding to the /etc/shorewall directory.

# /etc/shorewall/interfaces
?FORMAT 2
###############################################################################
#ZONE           INTERFACE               OPTIONS
lan             eth0                    dhcp
yfi             wlan0                   dhcp

# /etc/shorewall/zones
###############################################################################
#ZONE           TYPE            OPTIONS         IN_OPTIONS      OUT_OPTIONS
fw              firewall
lan             ip
yfi             ip

# /etc/shorewall/policy
###############################################################################
#SOURCE     DEST    POLICY  LOGLEVEL        RATE    CONNLIMIT
fw          all     ACCEPT
lan         all     ACCEPT
yfi         all     ACCEPT
all         all     REJECT

# /etc/shorewall/rules
######################################################################################################################################
#ACTION     SOURCE      DEST    PROTO   DPORT   SPORT   ORIGDEST    RATE    USER    MARK    CONNLIMIT   TIME    HEADERS SWITCH  HELPER
?SECTION ALL
?SECTION ESTABLISHED
?SECTION RELATED
?SECTION INVALID
?SECTION UNTRACKED
?SECTION NEW

# /etc/shorewall/snat
?FORMAT 2
#######################################################################################################################
#ACTION     SOURCE          DEST    PROTO   DPORT   SPORT   IPSEC   MARK    USER    SWITCH  ORIGDEST        PROBABILITY
MASQUERADE  10.10.17.0/24   eth0

Reboot

Now would be a good time to reboot for the some of the key changes to take effect.

Testing

Now that we have everything installed and configured everythinbg we can test the setup. Lets try and start the services and check the logs for its status.

Testing


# Reload Configs
systemctl daemon-reload

# GPSD
systemctl start gpsd
systemctl status gpsd
>>● gpsd.service - GPS (Global Positioning System) Daemon
>>     Loaded: loaded (/lib/systemd/system/gpsd.service; enabled; preset: enabled)
>>     Active: active (running) since Tue 2024-05-21 08:32:03 BST; 1 week 4 days ago
>>TriggeredBy: ● gpsd.socket
>>    Process: 296 ExecStart=/usr/sbin/gpsd $GPSD_OPTIONS $OPTIONS $DEVICES (code=exited, status=0/SUCCESS)
>>   Main PID: 304 (gpsd)
>>      Tasks: 4 (limit: 387)
>>        CPU: 3min 4.437s
>>     CGroup: /system.slice/gpsd.service
>>             └─304 /usr/sbin/gpsd -n -G -r -b /dev/ttyAMA0 /dev/pps0

---------------------


# GPSD Socket
systemctl start gpsd.socket
systemctl status gpsd.socket
● gpsd.socket - GPS (Global Positioning System) Daemon Sockets
     Loaded: loaded (/etc/systemd/system/gpsd.socket; enabled; preset: enabled)
     Active: active (running) since Tue 2024-06-04 11:10:43 BST; 9min ago
   Triggers: ● gpsd.service
     Listen: /run/gpsd.sock (Stream)
             [::1]:2947 (Stream)
             0.0.0.0:2947 (Stream)
      Tasks: 0 (limit: 387)
        CPU: 11ms
     CGroup: /system.slice/gpsd.socket

---------------------



# HOSTAPD
systemctl start hostapd
systemctl status hostapd
>>● hostapd.service - Access point and authentication server for Wi-Fi and Ethernet
>>     Loaded: loaded (/lib/systemd/system/hostapd.service; enabled; preset: enabled)
>>     Active: active (running) since Tue 2024-05-21 08:32:38 BST; 1 week 5 days ago
>>       Docs: man:hostapd(8)
>>    Process: 799 ExecStart=/usr/sbin/hostapd -B -P /run/hostapd.pid $DAEMON_OPTS ${DAEMON_CONF} (code=exited, status=0/SUCCESS)
>>   Main PID: 808 (hostapd)
>>      Tasks: 1 (limit: 387)
>>        CPU: 364ms
>>     CGroup: /system.slice/hostapd.service
>>             └─808 /usr/sbin/hostapd -B -P /run/hostapd.pid -T -i wlan0 /etc/hostapd/hostapd.conf

---------------------

# SHOREWALL
systemctl start shorewall
systemctl shorewall
>>● shorewall.service - Shorewall IPv4 firewall
>>     Loaded: loaded (/lib/systemd/system/shorewall.service; enabled; preset: enabled)
>>     Active: active (exited) since Tue 2024-05-21 08:32:49 BST; 1 week 5 days ago
>>       Docs: man:shorewall(8)
>>    Process: 804 ExecStart=/sbin/shorewall $OPTIONS start $STARTOPTIONS (code=exited, status=0/SUCCESS)
>>   Main PID: 804 (code=exited, status=0/SUCCESS)
>>        CPU: 2.006s

---------------------

# DNSMASQ
systemctl start dnsmasq
systemctl status dnsmasq
>>● dnsmasq.service - dnsmasq - A lightweight DHCP and caching DNS server
>>     Loaded: loaded (/lib/systemd/system/dnsmasq.service; enabled; preset: enabled)
>>     Active: active (running) since Tue 2024-05-21 08:32:43 BST; 1 week 5 days ago
>>    Process: 798 ExecStartPre=/etc/init.d/dnsmasq checkconfig (code=exited, status=0/SUCCESS)
>>    Process: 867 ExecStart=/etc/init.d/dnsmasq systemd-exec (code=exited, status=0/SUCCESS)
>>    Process: 883 ExecStartPost=/etc/init.d/dnsmasq systemd-start-resolvconf (code=exited, status=0/SUCCESS)
>>   Main PID: 881 (dnsmasq)
>>      Tasks: 1 (limit: 387)
>>        CPU: 595ms
>>     CGroup: /system.slice/dnsmasq.service
>>             └─881 /usr/sbin/dnsmasq -x /run/dnsmasq/dnsmasq.pid -u dnsmasq -7 /etc/dnsmasq.d,.dpkg-dist,.dpkg-old,.dpkg-new --local-service ...

---------------------

# NTPSEC
systemctl start ntpsec
systemctl status ntpsec
>>● ntpsec.service - Network Time Service
>>     Loaded: loaded (/lib/systemd/system/ntpsec.service; enabled; preset: enabled)
>>     Active: active (running) since Sun 2024-06-02 07:54:58 BST; 32min ago
>>       Docs: man:ntpd(8)
>>    Process: 1051 ExecStart=/usr/libexec/ntpsec/ntp-systemd-wrapper (code=exited, status=0/SUCCESS)
>>   Main PID: 1054 (ntpd)
>>      Tasks: 1 (limit: 387)
>>        CPU: 1.951s
>>     CGroup: /system.slice/ntpsec.service
>>             └─1054 /usr/sbin/ntpd -p /run/ntpd.pid -c /etc/ntpsec/ntp.conf -g -u ntpsec:ntpsec

---------------------

Pulse Per Second Testing

To test PPS the use the following command ...

sudo ppstest /dev/pps0
>> trying PPS source "/dev/pps0"
>> found PPS source "/dev/pps0"
>> ok, found 1 source(s), now start fetching data...
>> source 0 - assert 1717496861.999777250, sequence: 11818 - clear  0.000000000, sequence: 0
>> source 0 - assert 1717496862.999787146, sequence: 11819 - clear  0.000000000, sequence: 0

Testing GPS

To test GPS the use the following command ...

gpsmon
>> tcp://localhost:2947          NMEA0183>
>> ┌────────────────────────────────────────────────────────────────────────────┐
>> │Time: 2024-06-04T10:32:56.000Z   Lat: 52 29.820790' N   Lon:   1 03.292980' E             │
>> └───────────────────────────────── Cooked TPV ─────────────────────────────────┘
>> ┌────────────────────────────────────────────────────────────────────────────┐
>> │ GPGGA GPGSA GPGSV GPGLL GPRMC GPVTG                                                      │
>> └───────────────────────────────── Sentences ──────────────────────────────────┘
>> ┌───────────────────────┌────────────────────────┌──────────────────────────┐
>> │GP  1    1 162  9  0  N    │Latitude:   5229.82079 N     │Latitude:  5229.82082         │
>> │GP  2    2 244  5 26  N    │Longitude: 00103.29298 E     |Longitude: 00103.29296        │
>> │GP  7    7 298 17 40  N    │Speed:    0.003              │Altitude:  60.0               │
>> │GP  8    8 289 51 29  N    │Course:                      │Quality:   1   Sats: 11       │
>> │GP 10   10 135 48 17  N    │Status:   A        FAA:A     │HDOP:      0.78               │
>> │GP 10   10 135 48 27  N    │MagVar:                      │Geoid:     45.8               │
>> │GP 13   13   8  5 11  N    └───────── RMC ───────────└─────────── GGA ──────────┘
>> │GP 13   13   7  5 36  N   ┌─────────────────────────┌──────────────────────────┐
>> │GP 15   15  36 10 26  N   │Mode: A3 Sats:                │UTC:           RMS:           │
>> │GP 15   15  36 10 41  N   │DOP H=0.78 V=1.04 P=1.30      │MAJ:           MIN:           │
>> │GP 16   16 186 49 25  N   │TOFF:  0.152009469            │ORI:           LAT:           │
>> │GP 16   16 186 49 28  N   │PPS: -0.000225011             │LON:           ALT:           │
>> └───v──── GSV ──────────└────── GSA + PPS ──────────└─────────── GST ──────────┘

Dump1090 Testing

To Be Continued ...

Testing
Startup script for systemd

The only thing that is left to do is to create a startup script for dump1090 to start at boot. and we shall do that another day.

Enable Servcies to start at boot

If all has gone well you should now be able to enable the services to start at boot.




sudo systemctl enable gpsd
sudo systemctl enable gpsd.socket
sudo systemctl enable hostapd
sudo systemctl enable dnsmasq
sudo systemctl enable ntpsec
sudo systemctl enable shorewall

Conclusion

If everything went according to plan then you will have a Raspberry Pi that is a Stratum 1 NTP server, a ADSB server and a network server. Diagram of the setup below.


 (o_            (    )
   //\            |\^^/|  
 \_/_           (O::O)
 ----------------\\//-
Penguin Dragon  (oo)
 ---------------------

Overview

Table of Contents

The Hardware

The Software

Hardware Setup

Software Installation

Raspberry Pi

Raspberry Setup

Tools

Dump1090

The Configuration

/boot/firmware/cmdline.txt

/boot/firmware/config.txt

/etc/modules

/etc/network/interfaces

/etc/default/gpsd

/etc/systemd/system/gpsd.socket

/lib/systemd/system/gpsd.socket

/etc/default/dnsmasq

/etc/dnsmasq/dnsmasq.conf

/etc/default/ntpsec

/etc/ntpsec/ntp.conf

/etc/default/hostapd

/etc/hostapd/hostpad.conf

/etc/default/shorewall

/etc/shorewall/shorewall.conf

/etc/shorewall/*

Reboot

Testing

Testing

Pulse Per Second Testing

Testing GPS

Dump1090 Testing

Enable Servcies to start at boot

Conclusion