Air780EG Additional instructions#

Air780EG It is Air780E + GNSS chip 6228, so 95% of the characteristics are the same as Air780E. Here are different places to say.

GPS/GNSS Belonging to a bunch of things, the following, unless otherwise specified, refers to “satellite positioning system.””

Internal wiring#

UART Part:

  1. Air780EG The GPS chip is connected toUART2/AUX_UART, so this port is occupied

  2. Because of the characteristics of UART, although it leads to UART2_RX, it is not possible to directly send instructions to GPS chip by external data line, and it is necessary to send the code from inside 780e.

  3. The default baud rate is 115200

  4. The instructions used are the same as the Air510U, Air510U Materials Website

Power supply part:

  1. Air780EG The GPS power supply is GPIO13/PAD12, note isPAD12/padaddr 12, not PAD28

  2. The power supply of the chip and the power supply of the active antenna are controlled together, using only one GPIO and one API control.

  3. Because normal GPIO is used, SLEEP1/LIGHT/SLEEP2/DEEP/HIB mode will power down

  4. In lua code, the control power supply API is pm.power(pm.GPS, true). although there is pm.GPS_ANT, it is invalid for Air780EG

  5. Flight mode is RF-related control and does not affect GPIO power supply, so it does not affect GPS power supply

  6. The new Air780EG is powered on and controlled by ‘GPIO23’, which is turned on by default.

Special note on new Air780EG#

The newly shipped Air780EG has added standby power to support hot start.

How to tell whether it is new or not: look at the factory time, the factory after 2023.8.7 is new.

Query method: IMEI production record query of Hecheng ERP, enter imei number to query. If you do not register, please register first. Registration is free of charge..

Positioning characteristics#

For a detailed description, please refer to the Air780EG hardware design manual, here to pick the focus, but also add some details

  1. The old model does not have backup power supply, the new model has backup power, and those with backup power can start hot.

  2. It is a “read-only version” of GPS chip, which means that all configuration items cannot be saved, and ephemeris/time/reference coordinates cannot be saved.

  3. With the blessing of the active antenna, the first positioning time without AGPS is less 30s

  4. When the three elements are complete (ephemeral/reference coordinate /UTC time), if the signal is good, the first positioning success can be less than 2 seconds.

  5. The output coordinate system is WGS84, that is, GPS coordinate system, which should be converted into GCJ02 or BD09 and other domestic coordinate systems when used in domestic maps..

  6. GPS Coordinate correction website

Auxiliary Positioning Correlation#

The built-in GPS chip loses all data after power failure, so auxiliary positioning depends on Cat in the Air780EG. 1 Capability of the chip

  1. ephemeris, download from a co-server via http

  2. Reference coordinates, two methods, base station positioning library ‘lbsLoc’ or ‘lbsLoc2’, the last successful positioning coordinates are stored in the file system

  3. UTC Time, China Mobile/China Telecom, the base station will issue the time (system eventNTP_UPDATE) after networking, China Unicom, NTP. For example, the API in lua issocket.sntp()

About Ephemeris#

  1. The ephemeris provided by the Zhou is GPS Beidou, both constellations have a size of about 5kb, updated every half hour

  2. GPS The valid time of the ephemeris is 4 hours

  3. The effective time of the Big Dipper ephemeris is 1 hour

  4. Measurements indicate that the Big Dipper ephemeris is helpful, but the main force is GPS ephemeris.

  5. Again, the GPS chip itself cannot save the ephemeris, the old model will be lost even if it is powered off, and the new model will be lost if it is powered off.!!

About Power Consumption#

  1. There are many states: star search state (60 ~ 100ma), continuous tracking state (40 ~ 60ma), standby state (200 ~ 500ua), and power-down state(0)

  2. No low-power instructions, no low-power instructions, no low-power instructions

  3. No low power mode, no low power mode, no low power mode

  4. The new model only has the standby power state, and’ GPIO23’ is used to control the standby power on or off, and the default is power on.

About Packaging and Software#

  1. External package, Air780E and Air780EG are the same, the difference is that UART2 cannot connect other equipment

  2. AT Firmware needs V1112 or above, and LuatOS firmware needs V1103 or above to have full support for Air780EG

Development Board pinout#

The default will not automatically boot, to * * long press pwrkey key for 2 seconds to boot**

The power light is on when the power is connected, * * when the power light is on, it does not mean that the power is on * *, and COM equipment will only appear when the computer is connected and turned on.

Please note the difference with the Air780E development board:

  1. UART2 No more multiplexing of GPIO10/11

  2. UART2_RX Do not connect external input

  3. To connect the GNSS antenna, the development board is equipped with an active GNSS antenna, and the board is equipped with a 4G antenna, which does not participate in positioning. Positioning cannot be successful without connecting the GNSS antenna..

  4. Air780EG Support passive and active antennas, the development board is matched with the active GNSS antenna by default.

Development board pin size:

  1. Distance between pins, 10mil, 2.54mm

  2. Distance between two rows of pins, 700mil, 17.78mm

The keys on the development board are BOOT(GPIO0), RESET (reset), PWR (power-on button) LED lights(GPIO27)

Development board PinOut diagram