Simulated GPS data on nRF9160 DK Asset Tracker Example

[iotlight]

I found lines 766 - 768

CONFIG_GPS_SIM_DEV_NAME="GPS_SIM"
CONFIG_GPS_SIM_BASE_LATITUDE=6325280
CONFIG_GPS_SIM_BASE_LONGITUDE=1026201

in \ncs\nrf\samples\nrf9160\asset_tracker\build\zephyr\.config

 

Please let me know how to change to the location in US such as Los Angeles, California for my upcoming demo

34.0522° N, 118.2437° W

Thanks.

[AndreasF]

Hi.

CONFIG_GPS_SIM_BASE_LATITUDE is calculated by the following steps:

Start-point latitude for simulated GPS data, from which the generated data will continue.
Calculated by deg * 100000 + minutes * 1000, for example 63 deg 25.280’N will be 6325280. 
Positive values are North, while negative values are South.

So 32.0522° N will be 3200000 + 5220 = 3205220

CONFIG_GPS_SIM_BASE_LONGITUDE is calculated by the following steps:

Start-point longitude for simulated GPS data, from which the generated data will continue. 
Calculated by deg * 100000 + minutes * 1000, for example 10 deg 26.201’E will be 1026201. 
Positive values are East, while negative values are West.

So 118.2437° W will be 11800000 + 2437000 = -14237000 since West are negative values.

Best regards,

Andreas

[iotlight]

I followed your instruction to change lines 23 and 34 in file \ncs\nrf\lib\gps_sim\Kconfig

Fullscreen Kconfig.txt Download

# Kconfig - GPS data simulator
#
# Copyright (c) 2018 Nordic Semiconductor
#
# SPDX-License-Identifier: LicenseRef-BSD-5-Clause-Nordic
#

menuconfig GPS_SIM
	bool "GPS simulator"
	help
	  Enable GPS simulator.

if GPS_SIM

config GPS_SIM_DEV_NAME
	string "GPS simulator device name"
	default "GPS_SIM"
	help
		GPS simulator device name.

config GPS_SIM_BASE_LATITUDE
	int "Base latitude for GPS data"
#	default 6325280
    default 3405220
	help
		Start-point latitude for simulated GPS data,
		from which the generated data will continue.
		Calculated by deg * 100000 + minutes * 1000 N,
		for example 63 deg 25.280' will be 6325280.

config GPS_SIM_BASE_LONGITUDE
	int "Base longitude for GPS data"
#	default 1026201
	default -14237000
	help
		Start-point longitude for simulated GPS data,
		from which the generated data will continue.
		Calculated by deg * 100000 + minutes * 1000 E,
		for example 10 deg 26.201' will be 1026201.

config GPS_SIM_BASE_TIMESTAMP
	int "Base timestamp for GPS data"
	default 134627
	help
		Timestamp at which the simulator will start counting.
		Format is hour * 10000 + min * 100 + sec, which means that
		13:46:27 becomes 134627.

config GPS_SIM_ELLIPSOID
	bool "Generate ellipsoid GPS path"
	default y
	help
		GPS simulator will create a path that goes in an ellipsoid
		shape.

config GPS_SIM_PSEUDO_RANDOM
	bool "Use pseudo-random values to generate GPS coordinates"
	help
		Enables pseudo-random GPS coordinate creation. Based on uptime
		that's input to a sine function, which causes the otuput
		to not be uniformally distributed, but sinusoidal.

config GPS_SIM_DYNAMIC_VALUES
	bool "GPS simulator dynamically creates data values"
	default y
	select NEWLIB_LIBC
	select NEWLIB_LIBC_FLOAT_PRINTF
	help
		Enables dynamically created simulator otuput as opposed
		to static values.

config GPS_SIM_MAX_STEP
	int "Maximum step size each iteration"
	default 5
	help
		Sets the maximum step size that can be taken in latitude or longitude
		for each simulation iteration. In units of 1/1000 degrees.

config GPS_SIM_TRIGGER
	bool "GPS simulator trigger"
	help
		Enable trigger. When enabled, it will emit 'data ready'
		trigger event time either by button press or at specified
		timer intervals.

if GPS_SIM_TRIGGER

choice
	prompt "Trigger type"
	depends on GPS_SIM_TRIGGER
	default GPS_SIM_TRIGGER_USE_TIMER
	help
		Specify the type of trigger that will be used to emit the
		'data ready' trigger event.

config GPS_SIM_TRIGGER_USE_TIMER
	bool "Use timer for trigger"
	help
		Use timer to trigger 'data ready' event.

config GPS_SIM_TRIGGER_USE_BUTTON
	bool "Use button 2 as trigger"
	help
		Use button 2 to trigger 'data ready' event.

endchoice

if GPS_SIM_TRIGGER && GPS_SIM_TRIGGER_USE_TIMER
	config GPS_SIM_TRIGGER_TIMER_MSEC
		int "Time between triggers, in milliseconds"
		default 1000
		help
			The time interval between each 'data ready' trigger event.
endif

if GPS_SIM_TRIGGER && !GPS_SIM_TRIGGER_USE_TIMER
	config GPS_SIM_TRIGGER_TIMER_MSEC
		int
		default 0
endif

config GPS_SIM_THREAD_PRIORITY
	int "Thread priority"
	depends on GPS_SIM_TRIGGER
	default 10
	help
	  Priority of thread used by the driver to handle interrupts.

config GPS_SIM_THREAD_STACK_SIZE
	int "Trigger thread stack size"
	depends on GPS_SIM_TRIGGER
	default 512
	help
	  Stack size of thread used by the driver to handle interrupts.

endif #GPS_SIM_TRIGGER

module = GPS_SIM
module-str = GPS simulator
source "${ZEPHYR_BASE}/subsys/logging/Kconfig.template.log_config"

endif #GPS_SIM

It seems like it showed the LA lat and long in the Messages, but I lost the map

 

Please let me know how to make the map shown Los Angeles, California.

Thanks.

[AndreasF]

Hi.

I'm unsure on whats happend with the map and I have reported this to the development team.

Best regards,

Andreas

[Markus Tacker (he/him)]

The correct values for longitude is -11814.622

The entire NMEA sentence for the coordinates is

$GPGGA,134708.200,3405.217,N,-11814.622,E,1,12,1.0,0,0,M,0,0,M,,*45

[iotlight]

I used Los Angeles decimal coordinates 34.0522308, -118.2436829

The messages seems correct, but the map is shown Japan, not Los Angeles, California.

Below is using Los Angeles DMS Coordinates as you suggested -11814621 in longitude

Please advise.