Properties

Configuration, status and telemetry download from the device is handled using a number of property variables. Each variable has a type (signed/unsigned integers, floating point numbers, strings, etc.) and a default value. Some properties are used for configuration and can be modified and stored in (optionally write-protected) non-volatile memory. Others are read-only and used for telemetry purposes. Some property changes take effect immediately, while others require a store and a system reset after update.

The system properties are divided into a number of property groups, each covering a specific part of the firmware.

Property values can be listed, modified and stored using the prop debug shell commands or remotely through the Property Client Library. As an example, to change the CSP address of the device to 21 and the default interface to RS422/KISS, run:

[polaris] prop get sys.csp.address
23
[polaris] prop set sys.csp.address 21
[polaris] prop set sys.csp.routes "0/0 KISS"
[polaris] prop unlock sys
[polaris] prop save sys
[polaris] prop unlock -f sys
[polaris] prop save -f sys
[polaris] reboot
...
[polaris] prop get sys.csp.address
21
[polaris] prop get sys.csp.routes
"0/0 KISS"

System Group

The sys group contains system parameters which remain fixed after launch. The group can be stored twice in boot and fallback configuration. Both are write-protected and must be unlocked using prop unlock sys before they can be written to.

Property

Type

Default

Description

sys.name

string

polaris

String name for system

sys.serial

uint32

Serial number/ID of the device

sys.sw.version

uint32

Running software version

sys.bootcount

uint32

Number of times the system was booted

sys.csp.address

uint8

23

CSP address of the device

sys.csp.routes

string

Additional CSP routes in CIDR notation

sys.can.rate

uint32

1000000

CAN-bus bitrate

sys.uart.rate

uint32

1000000

UART baudrate

sys.uart.multidrop

bool

false

UART multidrop mode (only drive bus on transmit)

Configuration Group

The conf group contains runtime settings. The group can be stored to the boot configuration and is not write protected.

Property

Type

Default

Description

conf.led.enable

bool

false

Onboard LEDs enabled

conf.power.fpga

bool

false 1

FPGA power channel

conf.power.rf

bool

false 1

RF power channel

conf.power.sdcard

bool

false

SD-card power channel

conf.power.eth

bool

false

Ethernet power channel

conf.fs.mount

bool

false

SD-card filesystem mount

1(1,2)

The power channels are powered off at boot time, but powered on when the demodulator starts.

Telemetry Group

Telemetry values are stored in the tm group and updated once every second. The group does not support storage.

Property

Type

Default

Description

tm.temp.mcu

int16

0

MCU package temperature in 1/100 ℃

tm.temp.fpga

int16

0

FPGA junction temperature in 1/100 ℃

tm.temp.power

int16

0

Power regulators temperature in 1/100 ℃

tm.temp.lna

int16

0

LNA temperature in 1/100 ℃

tm.temp.adc

int16

0

ADC temperature in 1/100 ℃

tm.temp.sdcard

int16

0

SD-card temperature in 1/100 ℃

tm.volt.vin

uint16

0

Input voltage in mV

tm.volt.3v3

uint16

0

3.3 V rail voltage in mV

tm.volt.2v0

uint16

0

2.0 V rail voltage in mV

tm.volt.1v0

uint16

0

1.0 V rail voltage in mV

tm.cur.vin

int16

0

Input current in mA

tm.cur.3v3

int16

0

3.3 V rail current in mA

tm.cur.2v0

int16

0

2.0 V rail current in mA

tm.cur.1v0

int16

0

1.0 V rail current in mA

tm.power.vin

uint16

0

Input power in mW

tm.power.3v3

uint16

0

3.3 V rail power in mW

tm.power.2v0

uint16

0

2.0 V rail power in mW

tm.power.1v0

uint16

0

1.0 V rail power in mW

Demodulator Group

The demod group contains configuration and information on the demodulator. The group can be stored to the boot configuration and is not write protected.

Property

Type

Default

Description

demod.enable

bool

true

Enable or disable demodulator

demod.filter

uint32

0x20000

Mode-S DF filter. Default is DF17 only.

demod.apframe

uint8

2

Number of frames required to accept AP frames

demod.timeout

uint16

60

Timeout in seconds before ICAOs are purged from cache

demod.decoded

uint32

Number of decoded messages with correct CRC

demod.unknown

uint32

Number of AP frames received from unknown ICAOs

demod.invalid

uint32

Number of frames received with unknown DF type

demod.dropped

uint32

Number of frames dropped due to lack of resources

demod.rate

uint16

Number of frames received in the last second

demod.rate.max

uint16

Maximum number of frames received in one second

demod.rate.avg

uint16

Average number of frames received in one second in the last minute

demod.rf.gain

float

0.0

Front end RF gain in dB

demod.pps.valid

bool

Valid PPS signal received

demod.pps.last

uint32

Number of sample clocks in last PPS cycle

demod.pps.avg

uint32

Average number of sample clocks in PPS cycle

Store Group

The ADS-B message store is controlled and monitored through the store group. The group can be stored to the boot configuration and is not write protected.

Property

Type

Default

Description

store.enable

bool

true

Enable or disable message store

store.seq

uint32

Last sequence number stored

store.stored

uint32

Number of frames currently stored

store.dropped

uint32

Number of frames dropped due to lack of resources