reported Timing Issue

[Florence201]

I’ve noticed approximately 1 minute difference from mission minutes to DED minutes. Zulu hour offset seems ok most of the time 

[WHOGX5]

The time starts at Zulu but the clock doesn't actually start ticking until your aircraft is powered up, that's why it's always delayed. For this reason you need to do a time hack to make sure the indicated time is correct. Afaik this is done in real life as well where wristband watches are synced during the briefing and then the aircraft time is synced when you've stepped.

[Terzi]

9 hours ago, WHOGX5 said:

The time starts at Zulu but the clock doesn't actually start ticking until your aircraft is powered up, that's why it's always delayed. For this reason you need to do a time hack to make sure the indicated time is correct. Afaik this is done in real life as well where wristband watches are synced during the briefing and then the aircraft time is synced when you've stepped.

I haven't tested it but if it is true, then it is really a bug @BIGNEWY. I don't think that such simple and important issue would be left to pilots while the onboard systems can just read the correct time precisely, while our simplest watches can do it as well.

[BIGNEWY]

I am looking into it, as I understand it the TOD time-of-day should allow for the synchronisation of the time. I will ask the team in the morning. 

 

thanks

[BIGNEWY]

I've tested MP and the time in the IPC seems correct and synced to UTC as expected. Let me know if you see different. 

 

thanks

[Dee-Jay]

I do confirm that in the plane, time it has to be in Zulu. If not synced on Zulu time, some systems should not work properly.

[WHOGX5]

As I said, time is not correct in cold started F-16s. As I do not use hot start I don't know if it applies to those slots as well. You can simply compare your time in the DED it to the time in the F10 view. Time will be set to zulu but it won't start counting until the aircraft is powered up so the minutes and seconds will be offset by however long it takes for you to power up your aircraft. We even have time synchronization in our community SOP as a mandatory step for all F-16 pilots as everyone's clocks will display a different time and none of them will be correct.

[=Panther=]

2 hours ago, WHOGX5 said:

As I said, time is not correct in cold started F-16s. As I do not use hot start I don't know if it applies to those slots as well. You can simply compare your time in the DED it to the time in the F10 view. Time will be set to zulu but it won't start counting until the aircraft is powered up so the minutes and seconds will be offset by however long it takes for you to power up your aircraft. We even have time synchronization in our community SOP as a mandatory step for all F-16 pilots as everyone's clocks will display a different time and none of them will be correct.

I see the same issue as well. We always need someone to look at F10 and call a HACK if we have a TOT critical mission. Two jets can ramp start and have two different times on their systems.

[Machalot]

Seems like the Viper should be able to use GPS time, which would be accurate within micro- or nanoseconds across all jets in a given theater.  Anyone know if the real jet can do this? 

[Terzi]

Let's say that the mission starts at 5:00 AM in Syria. We have Hornets and Vipers in the mission in MP server. After the ramp start, in multiplayer we confirmed that the F/A-18C shows the correct time as; let's say 5:13. The Viper on the other hand shows as (UTC 2:13 - minus the time spent without electric). Showing the time in UTC is acceptable. But each aircraft will startup in different seconds or minutes, thus showing the wrong time for each jet.

 

So the Hornets took off in exact time, while the Vipers were thinking there is still 2 more minutes until the takeoff time. Because the Vipers got their generators on after ~2 minutes. We confirmed this but currently I have no proof. Please investigate this and let me know if you really need some sort of video to verify this.

[Florence201]

Well known, hence why we do a time hack prior to taxi for Viper Flight. You could also have the mission commander call a time back over the radio

 

For real, watches are hacked at the brief, then jets set with watch time 

Edited March 26, 2021 by Florence201

[Machalot]

4 hours ago, Florence201 said:

Well known, hence why we do a time hack prior to taxi for Viper Flight. You could also have the mission commander call a time back over the radio

 

For real, watches are hacked at the brief, then jets set with watch time 

 

I wonder why the Viper can't use GPS time. 

[Florence201]

13 minutes ago, Machalot said:

I wonder why the Viper can't use GPS time. 

Because the model we have has an INS, hence why you align it 

[Frederf]

The DCS F-16 does have GPS-INS and the system time is set (by default) by GPS time. Which source for time (GPS or manual) and setting the manual time is done through the TIME page.

[Machalot]

1 hour ago, Florence201 said:

Because the model we have has an INS, hence why you align it 

Yes, but having to align an INS has nothing to do with the presence or absence of GPS.  GPS is a source of position and time while INS alignment (aka gyrocompassing) finds the attitude by measuring Earth rotation. 

28 minutes ago, Frederf said:

The DCS F-16 does have GPS-INS and the system time is set (by default) by GPS time. Which source for time (GPS or manual) and setting the manual time is done through the TIME page.

So by the OP's issue with timing mismatch, does that mean the default is manual? 

Edited March 27, 2021 by Machalot

[Frederf]

It means DCS is not modeling GPS-sourced system time at all.

[Terzi]

It makes sense to have manual correction for the time settings. But if the jet can sync with the satellites automatically, then we should have this already. I see no point in setting the time manually in every flight. There is no such operation in real-life ramp start procedure that I got from own sources. Let's wait for ED to comment on this; why they made it so, or are they gonna do further work on this.

[deadpool]

On 3/27/2021 at 3:44 AM, Florence201 said:

Because the model we have has an INS, hence why you align it 

 

Just as background information:
Every modern fighter jet will have INS at the core of it. You can correct for drift using GPS, absolutely, but worst case, GPS is either toast due to anti-sat-weapons or it's being jammed or your gps receiver refuses to work for whatever reason.

 

Think of GPS only as one source that can keep accuracy up.

[BIGNEWY]

I will look into it, but I need evidence. I have asked the team and we will be asking our SME's

 

thanks

[Terzi]

@BIGNEWY

 

 

The time that is passed without electricity during startup causes shift in system time. Here I boosted the time on purpose before the ramp start and the result is ~5min shift.

[BIGNEWY]

Hi,

 

I have made a report for the team but we are still looking for evidence for the synchronisation of time.

 

thanks

[Terzi]

3 hours ago, BIGNEWY said:

Hi,

 

I have made a report for the team but we are still looking for evidence for the synchronisation of time.

 

thanks

Video was not enough? How can I help more? By evidence, do you mean that the real F-16 time sync process?

[BIGNEWY]

3 minutes ago, Terzi said:

Video was not enough? How can I help more? By evidence, do you mean that the real F-16 time sync process?

 

The video was fine to show the issue, the problem is finding the correct information on how it is actually modelled in real life and how it ties into the other system.

 

[Terzi]

15 minutes ago, BIGNEWY said:

 

The video was fine to show the issue, the problem is finding the correct information on how it is actually modelled in real life and how it ties into the other system.

 

I was reading the HAF document. It is really so that ED model was right to pause the clock without power on the FCC and it will continue from the last known time when the power is back on. (section 1-303 to 1-306) This is very nice when there is no GPS signal.

 

1-253:

"When the receiver has valid cryptokeys loaded and is tracking four satellites, accurate position, velocity and time data are provided to the aircraft ...."

 

1-255:

"The GPS provides:

...

...

Time of day

GPS data is also used in have-quick syncronization"

[Frederf]

Since time-input to L16 or VHF, UHF radios aren't modeled system time is the only affected system I know of. Anything GPS position related (DTC load of crypto keys, PPS v SPS, blah blah) is a separate issue. GPS is on A MUX 1533 data and non-ess AC 1 power. Without UFC GPS functions as last left.

 

The entirety of interaction would be DED pages TIME and CRUS DTOS. System time (and date) initializes on power up to use GPS time when it comes online so it requires flipping the GPS switch and probably wait a brief time (initialization 4s?). TIME page has "GPS" label. Label is blanked when GPS not supplying system time (off, not ready yet, manually deselected). Deselection is by SEQ when on the TIME page or by manual entry of system time in CRUS DTOS page. When GPS is deselected then manual time/date entry on TIME page is allowed. I don't see any mention of how to get system time back on GPS source although it might be possible.