AUTOSURVEY

Survey for accurate position

Platform:

OEM719, OEM729, OEM7500, OEM7600, OEM7700, OEM7720, PwrPak7, CPT7, CPT7700, SMART7

The AUTOSURVEY command uses position averaging to automatically determine the position for a base station.

When the AUTOSURVEY command is sent, the receiver starts position averaging. The position averaging continues until a specified accuracy level is met or until the specified survey time expires. When position averaging is complete, the calculated position is saved as the fix position for the base station. This calculated position is then used when transmitting differential corrections to the rover.

The AUTOSURVEY command computes the base position in WGS84.

If the FIX command is entered by a user, the SAVECONFIG command must then be issued to save to NVM. If the FIX command is issued by the AUTOSURVEY feature, the SAVECONFIG command does not need to be issued, because it is automatically saved to NVM.

On subsequent power ups or resets, an AUTOSURVEY runs to determine if the base station has moved. As the AUTOSURVEY runs, the average position calculated is compared to the saved fix position. If the average position is within the AUTOSURVEY tolerance setting, the receiver assumes it has not moved and uses the previously saved fix position. If the average position is outside of the AUTOSURVEY tolerance setting, the receiver assumes it has moved and will continue calculating a position average until the accuracy level is met or until the specified survey time expires.

The surveyed positions saved using the AUTOSURVEY command can be viewed using the SAVEDSURVEYPOSITIONS log. Surveyed positions can be added or deleted using the SURVEYPOSITION command.

The maximum number of surveys that can be saved to memory is 32. If this number is exceeded, the new position entry will overwrite the last entry reported by the SAVEDSURVEYPOSITIONS log.

Message ID: 1795

Abbreviated ASCII Syntax:

AUTOSURVEY control [time] [accuracy] [tolerance] [save_nvm] [position_id]

Input Example:

In the following example, the receiver is set up to survey its position for up to 24 hours or until the averaged position accuracy is 10 cm. On subsequent power ups at the same location, the survey will terminate as soon as the receiver determines the position is within 4 m of its surveyed position. Once the receiver has fixed its position, it will transmit RTCMV3 corrections over COM2.

SERIALCONFIG COM2 115200 N 8 1 N ON

INTERFACEMODE COM2 NONE RTCMV3 OFF

LOG COM2 RTCM1004 ONTIME 1

LOG COM2 RTCM1012 ONTIME 1

LOG COM2 RTCM1006 ONTIME 10

LOG COM2 RTCM1033 ONTIME 10

LOG COM2 RTCM1019 ONTIME 120

AUTOSURVEY ENABLE 1440 .1 4

SAVECONFIG

Field

Field Type

ASCII Value

Binary Value

Description

Format

Binary Bytes

Binary Offset

1

Command header

-

-

AUTOSURVEY header

This field contains the command name for abbreviated ASCII or the message header for ASCII or Binary.

-

H

0

2

control

disable

0

Disables the self-survey feature and halts any self-survey related activity (default = disable)

Enum

4

H

enable

1

Enables the self-survey feature

3

time

1 - 6000 minutes

Maximum amount of time to perform self-survey
(default = 1440 minutes)

Ulong

4

H+4

4

accuracy

0 - 100 metres

Desired horizontal standard deviation
(default = 0.1 metres)

Float

4

H+8

5

tolerance

3 - 100 metres

Maximum distance between calculated position and saved position. During the self-survey, if the distance between the calculated position and the previously surveyed position is less than this value, the previous position is used.
(default = 10 metres)

Float

4

H+12

6

save_nvm

OFF

0

Do not save position in NVM

Enum

4

H+16

ON

1

Save position in NVM
(default = ON)

7

position_id

4 character string

ID for the saved position. If the ID is not specified or if the ID is entered as "AUTO", receiver automatically generates a unique ID for the position.

This ID is the ID for the surveyed position, not the station ID set using the DGPSTXID command.

String[5]

4 or 81

H+20