Error message "GNSS HEADING UNUSABLE" is displayed

Issue

GNSS HEADING UNUSABLE" is displayed.

Answer

Please review the following information to improve the situation. Please check.

Tip: GNSS HEADING UNUSUABLE is displayed when the information required to calculate the cutting edge position is not satisfactory and a FIX solution cannot be obtained.

To identify the cause, please review the most likely factors based on the following four points.

１．Changes	Changes before and after the error is displayed, such as a change in the operating location, a change in correction information, or a change in parts.
２．Environment	Satellite acquisition environment (high-voltage power lines, sky coverage), correction information acquisition environment (fixed station settings, baseline), etc.
３．Hardware	Loose GNSS antenna wiring, loose GNSS antenna fixing bracket, GNSS antenna failure, etc.
４．Others	Not performing machine calibration, poor GNSS antenna measurement during machine calibration, etc.

Factors that are likely to affect the display of GNSS HEADING UNUSABLE

1. Is the acquisition satellite environment secured?

2. Is the correction information set properly?

3. Is the hardware wiring loose, deteriorated, or broken?

4. Others (Is the machine calibration properly performed?)

Factors	How to deal
１．Is the acquisition satellite environment secured?
Is there anything blocking the GNSS antenna?	・If there are any devices that block the GNSS antenna, make sure they are not blocking the antenna. ・Work in an area free of high-voltage power lines, etc. ・Work in a location where the sky above the GNSS antenna is unobstructed by forests, valleys, etc. *If the sky coverage of the GNSS antenna is low, the number of satellites acquired may decrease and GNSS HEADING UNUSABLE may be more likely to appear.
Is the satellite flying condition good?	・Work only after the satellite tracking status of the site (area) recovers. *If the satellite coverage (number of satellites) is not good, GNSS HEADING UNUSABLE may be displayed because the information required to calculate the cutting edge position is not satisfactory (DOP value of 2.5 or less is recommended).
Is GNSS Type setting appropriate?	Review GPS, GLO, GAL, BDS, QZS settings

２． Is the correction information set properly?
Appropriate mount point is not selected (In case of Ntirp use)	・Select an appropriate mount point *Mount points are different for each correction information provider.
Is the baseline distance too far? (In case of Ntrip/radio)	・If using Ntrip, work within 10 km of the recommended baseline distance. ・If using a external radio, use the recommended environment for the radio. *The further away from the electronic reference station/fixed station, the less stable the accuracy tends to be.
The setting of the radio is not appropriate. (When using a radio)	・Set an appropriate external radio communication speed. (Recommended radio communication speed: 38400bps)
Fixed station settings and location are not appropriate. (In case of using Ntrip/radio)	・Select an appropriate mount point ・Review the fixed station's installation environment (is there anything obstructing the sky above the antenna?) ・Review the input coordinates (latitude and longitude) of the fixed station.

３．3. Is the hardware wiring loose, deteriorated, or broken?
Temporary problems are occurring.	・Perform a soft reset. From the machine guidance screen, select menu > "GNSS Settings" > "GNSS Basic Settings" > "Soft Reset".
	・Restart the engine.
Is there any loose wiring in the GNSS antenna?	・If there is any looseness in the wiring on the GNSS antenna side, retighten it. ・If there is any looseness in the wiring on the controller side, retighten it. *Wiring may loosen due to vibration during machine operation.
Is there looseness in GNSS antenna fixing bracket?	・If the bracket is loose, retighten the bracket and perform the machine calibration again.
Is the GNSS antenna broken?	・If the GNSS antenna is broken, replace it. [GNSS antenna failure or not] Check the satellite acquisition status of the GNSS antenna from the screen. If the GNSS antenna is not acquiring satellites, the cable around the GNSS antenna or the GNSS antenna may be broken. If one of the GNSS antennas is not acquiring satellites, switch the main/sub GNSS antenna and check the satellite acquisition status to isolate the faulty part.

４．Others
Machine calibration has not been performed. (Please confirm with your local distributor.)	・Carry out machine calibration.
Antenna measurements at the time of machine calibration are different from actual conditions. (Please confirm with your local distributor.)	・Calculate the distance between antennas from the "Main GNSS mount information" and "Sub GNSS mount information" of the machine calibration information. Refer to menu>Machine calibration settings>Machine calibration information Distance between antennas ＝ Measure the actual distance between the main antenna and the sub-antenna directly and compare if there is any difference between the two antennas. If there is a difference of 2.5 cm or more, re-calibrate the machine.
Communication of correction information is not stable.	・Ensure a stable wireless communication environment. ・Ensure a stable communication environment for mobile communication network.
Not performing the update to latest version.	・Ensure that the controller firmware and Smart Construction Pilot app are up-to-date.