eRide
OPUS 6/
eRide
OPUS 7 GV-86/ GV-87
Dead Reckoning User
’
s Guide
SE16-900-002-00
19
FURUNO ELECTRIC CO., LTD. All rights reserved.
6 Calibration
Calibration is a function to estimate the output errors of IMU sensor and vehicle speed pulse. Estimated output
errors are bias and gain. The bias is an output value when the input value is 0, and the gain is a ratio of the
input value to the output value. Using the estimated bias and gain, the GNSS+DR receiver corrects the output
value of IMU sensor and vehicle speed pulse, and outputs high precision position.
The calibration method is described in the following sections.
6.1 Power on to GNSS Position Fix
[Operation]
It is necessary to do position fix in open sky as a good GNSS signal reception environment
(*1)
before starting
calibration driving.
[Check]
1. Check the position fix status with GNS and RMC sentence
Make sure that the position fix status is A or D.
Example:
Yellow high-light shows the position fix status (GNS sentence shows the position fix status of GPS,
GLONASS and Galileo from left hand).
$GNRMC,071201.776,A,3442.7276,N,13520.1229,E,0.00,30.96,130614,,,A,V*3C
$GNGNS,071201.776,3442.7276,N,13520.1229,E,AAN,18,0.5,3.6,36.7,,,V*5C
2. Check the C/N0 value with GSV sentence
The more number of satellites with C/N0 with over 40 dB-Hz, the better reception environment.
Example:
Yellow high-light shows the C/N0 value.
$GPGSV,4,1,14,19,73,309,50,03,70,345,52,27,55,031,52,16,46,084,50,1*6A
$GPGSV,4,2,14,07,40,307,52,11,39,211,49,08,19,320,46,01,15,199,40,1*61
$GPGSV,4,3,14,13,15,247,43,30,13,319,,22,11,090,46,23,05,219,42,1*6F
$GPGSV,4,4,14,42,00,000,46,93,32,161,43,,,,,,,,,1*6F
$GLGSV,2,1,07,82,71,317,56,80,67,326,53,79,50,152,52,81,30,031,55,1*7C
$GLGSV,2,2,07,83,25,238,53,73,14,329,29,78,01,151,34,,,,,1*42
Notes:
(*1) As an index of a good GNSS signal reception environment, it is more than 50% of the number of satellites
in use with signal level of over 40 dB-Hz.
