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Drivers Manual

NovAtel OEM4 Family (BESTPOS Telegram) (UTC) - 12

Description

Interface Type

Driver to decode the BESTGPSPOS log format supports both serial as network UDP communication.
For the network driver please select the driver name that starts with "Network - NovAtel..."

Driver to decode the best available GPS position (without INS) computed by a NovAtel SPAN-CPT GPS/INS receiver, outputting the so-called BESTGPSPOS log format,

or to decode the best available combined GPS and inertial navigation system (if available) position computed by a NovAtel OEM4 Family receiver, outputting the so-called BESTPOS log format.


Driver Information

Driver NovAtel OEM4 Family (#BESTPOS Telegram)
NovAtel SPAN (#BESTGPSPOS Format) 
Interface Type Serial or Network Driver Class Type Terminated 
UTC Driver (question) Yes Input / Output Input  Executable DrvQPSTerminated.exe
DrvQPSTerminatedUDP.exe 
DrvQPSTerminatedTCP.exe
Related Systems
Related Pages  



Decoding Notes

  • The GPS time fields from the header are decoded, converted to UTC, and used for time-stamping in case your template setup supports PPS. Therefore it is important to set the correct UTC to GPS correction in your template setup (16 sec, as of July 2012)
  • The CRC32-bit checksum is by default decoded and used to check the data integrity. If the checksum fails, no data will be decoded, unless you use command-line parameter 'NOCS' (advanced user only!).
  • The Solution Status text (data field # 1) is decoded as number as defined in the Solution Status Table of the NovAtel manual:

    Solution Status

    Text

    Value

    Description

    SOL_COMPUTED

    0

    Solution computed

    INSUFFICIENT_OBS

    1

    Insufficient observations

    NO_CONVERGENCE

    2

    No convergence

    SINGULARITY

    3

    Singularity at parameters matrix

    COV_TRACE

    4

    Covariance trace exceeds maximum (trace > 1000 m)

    TEST_DIST

    5

    Test distance exceeded (maximum of 3 rejections if distance > 10 km)

    COLD_START

    6

    Not yet converged from cold start

    V_H_LIMIT

    7

    Height or velocity limits exceeded (in accordance with COCOM export licensing restrictions)

    VARIANCE

    8

    Variance exceeds limits

    RESIDUALS

    9

    Residuals are too large

    DELTA_POS

    10

    Delta position is too large

    NEGATIVE_VAR

    11

    Negative variance

    Reserved

    12

    Reserved

    INTEGRITY_WARNING

    13

    Large residuals make position unreliable

    INS_INACTIVE

    14

    INS has not started yet

    INS_ALIGNING

    15

    INS doing its coarse alignment

    INS_BAD

    16

    INS position is bad

    IMU_UNPLUGGED

    17

    No IMU detected

    PENDING

    18

    When a FIX POSITION command is entered, the receiver computes its own position

    INVALID_FIX

    19

    The fixed position, entered using the FIX POSITION command, is not valid

    UNAUTHORIZED

    20

    Position type is unauthorized - HP on a receiver not authorized for it

  • The Position Type text (data field # 2) is decoded as number as defined in the Position or Velocity Type Table of the NovAtel manual:

    Position Type

    Text

    Value

    Description

    NONE

    0

    No solution

    FIXEDPOS

    1

    Position has been fixed by the FIX POSITION command

    FIXEDHEIGHT

    2

    Position has been fixed by the FIX HEIGHT/AUTO command

    Reserved

    3

    Reserved (3-7)

    DOPPLER_VELOCITY

    8

    Velocity computed using instantaneous Doppler

    Reserved

    9

    Reserved (9-15)

    SINGLE

    16

    Single point position

    PSRDIFF

    17

    Pseudorange differential solution

    WAAS

    18

    Solution calculated using corrections from an SBAS

    PROPAGATED

    19

    Propagated by a Kalman filter without new observations

    OMNISTAR

    20

    OmniSTAR VBS position (L1 sub-meter

    Reserved

    21

    Reserved (21-31)

    L1_FLOAT

    32

    Floating L1 ambiguity solution

    IONOFREE_FLOAT

    33

    Floating ionospheric-free ambiguity solution

    NARROW_FLOAT

    34

    Floating narrow-lane ambiguity solution

    L1_INT

    48

    Integer L1 ambiguity solution

    WIDE_INT

    49

    Integer wide-lane ambiguity solution

    NARROW_INT

    50

    Integer narrow-lane ambiguity solution

    RTK_DIRECT_INS

    51

    RTK status where the RTK filter is directly initialized from the INS filter

    INS

    52

    INS calculated position type

    INS_PSRSP

    53

    INS

    INS_PSRDIFF

    54

    INS

    INS_RTKFLOAT

    55

    INS

    INS_RTKFIXED

    56

    INS

    OMNISTAR_HP

    64

    OmniSTAR HP position (L1/L2 decimeter)

    Reserved

    65

    Reserved

    CDGPS

    66

    Position solution using CDGPS correction

Database Setup

  • In order to decode the position from the BESTPOS or BESTGPSPOS message, add a Position Navigation System to your template and select the driver "NovAtel OEM4 Family (#BESTPOS Telegram) (With UTC)" or "NovAtel SPAN-CPT (#BESTGPSPOS Telegram) (With UTC)".
    It is important to select for the Horizontal and Vertical datum on the second wizard page the same datum as seen in data field #7, 'Datum ID' of the message telegram. Normally this will be the default 'WGS84' datum.
  • In order to decode separately the Position Type and/or the Solution Status field for monitoring these values, add a Miscellaneous System to your template, and select the driver "NovAtel OEM4 Family (#BESTPOS Telegram) (Status)" or "NovAtel SPAN-CPT (#BESTGPSPOS Telegram) (Status)".
    Select the same I/O parameters as for the defined Position Navigation System above.

    On the 2nd wizard page, add a Generic Observation, name it e.g. 'Position Type', and enter for Slot 1: 'POSTYPE'.
    For the Solution Status field add another Generic Observation and name it e.g. 'Solution Status'. Enter for the Slot 1: 'SOLSTATUS'.



    It is important that all Slot Id's are entered in capitals.

Online


For a Position Navigation System you can monitor the Solution Status as Solution mode in a Position System Display, as Calcmode in a Generic Display, or as Raw Alert 'Position Mode outside limit' in the Alert Display.

The other decoded fields, like base station Id, differential age, etc., can be monitored using a Position System Display or a Generic Display. Notice that the Position RMS is derived from the decoded Lat/Lon/Height Standard Deviation fields (#8, #9 and #10).

Note
Due to demand the Positioning System Display now shows under the Satellites tab, the number of satellites used in the solution, and not the number of satellites tracked.
The same applies to the Generic Display Satellite Count. The screen captures below illustrate this:


Position System Display


Generic Display