Future version 1.27 of the "World Map" #future
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Hi Simon. I have seen in the forecast of version 1.2.7 of the "World Map", an NTP client, would it be possible to implement the reading of the clock of a GPS (installed in a serial port)? It would be appreciated in areas or circumstances without internet connection . Thanks for your time. Antonio D. (EA7HGL)
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Siegfried Jackstien
My gps dongle came with an app to read data (and sync clock if needed) Also shows number of the sats and a sky view where each one is and reads ephemeridian data But included inside map soft?? Not a bad idea Dg9bfc sigi Am 10.05.2022 19:25 schrieb EA7HGL <ea7hgl@...>:
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Simon Brown
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From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of EA7HGL
Sent: 10 May 2022 18:25 To: main@SDR-Radio.groups.io Subject: [SDR-Radio] Future version 1.27 of the "World Map" #future
[Edited Message Follows] Hi Simon. I have seen in the forecast of version 1.2.7 of the "World Map", an NTP client, would it be possible to implement the reading of the clock of a GPS (installed in a serial port)? It would be appreciated in areas or circumstances without internet connection . Thanks for your time. Antonio D. (EA7HGL) -- - + - + -
Please use https://forum.sdr-radio.com:4499/ when posting questions or problems.
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jdow
You can do that using the PC version of Symmetricom's
ntp client. If not that there is a full up ntp server/client for
NTP out there on the web. One or both of those options should
include the standard com port. The accuracy may not be all that
great, though. There is a lot of latency variation with Windows.
And Windows time setting granularity is 1 ms when a program has
the multi-media timers active and set to 1 ms.
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{^_^}
On 20220510 10:25:09, EA7HGL wrote:
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jdow
This one looks intriguing, It has Windows driver. It
has PPS - sort of, via USB.
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Waterproof GPS Receiver for Laptop, USB Interface, Raspberry Pi, 27 db Gain I have NO idea why this caught be by surprise. There are people
who've done GPS using an RTL dongle. But, it did surprise me. And
it's only $35 Amazon Prime in the US. {o.o}
On 20220510 10:40:04, Siegfried
Jackstien wrote:
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Simon Brown
Hi,
I can tell you that with Windows & NTP setting the time results in either 0 or 1 ms offset, it’s good. An advanced NTP client talks with several NTP servers, determines round trip latency, performs long term analysis and generally results in a 0 ms offset.
The Windows time sync runs as a service using the local system account, there will be a small amount of latency with this approach.
From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of jdow
Sent: 11 May 2022 04:44 To: main@SDR-Radio.groups.io Subject: Re: [SDR-Radio] Future version 1.27 of the "World Map" #future
You can do that using the PC version of Symmetricom's ntp client. If not that there is a full up ntp server/client for NTP out there on the web. One or both of those options should include the standard com port. The accuracy may not be all that great, though. There is a lot of latency variation with Windows. And Windows time setting granularity is 1 ms when a program has the multi-media timers active and set to 1 ms. On 20220510 10:25:09, EA7HGL wrote:
-- - + - + -
Please use https://forum.sdr-radio.com:4499/ when posting questions or problems.
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Simon Brown
And,
Testing my device it shows a time resolution of just one second.
From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Simon Brown
Sent: 10 May 2022 21:36 To: main@SDR-Radio.groups.io Subject: Re: [SDR-Radio] Future version 1.27 of the "World Map" #future
Yes,
Could do that, I have such a device.
Simon Brown
From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of EA7HGL
[Edited Message Follows] Hi Simon. I have seen in the forecast of version 1.2.7 of the "World Map", an NTP client, would it be possible to implement the reading of the clock of a GPS (installed in a serial port)? It would be appreciated in areas or circumstances without internet connection . Thanks for your time. Antonio D. (EA7HGL)
- + - + - Please use https://forum.sdr-radio.com:4499/ when posting questions or problems. -- - + - + -
Please use https://forum.sdr-radio.com:4499/ when posting questions or problems.
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jdow
I presume you mean +/- 1 ms. Your phrasing was a
touch ambiguous. And that is only with the multimedia tick size
setting to 1ms. (By now setting to 0.1 ms should be allowed but I
suppose ms does not figure that's productive.
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{^_-}
On 20220510 22:21:51, Simon Brown
wrote:
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jdow
time_t timeGetTime(); That has millisecond resolution
- if running with mm timer set to 1 ms. Then there is the
precision (100ns) timer with motherboard dependent actual
resolution. I use timeGetTime() most of the time. One must handle
it's roll over, of course. With time64_to work with on 64 bit
builds that's not much of a problem. It is always a relative time
to when the computer boots. But that offset can be backed out if
critical.
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{^_^}
On 20220511 00:10:26, Simon Brown
wrote:
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On 11/05/2022 09:37, jdow wrote:
time_t timeGetTime(); That has millisecond resolution - if running with mm For getting the UTC I use the precise function where it is available, which should be Windows-8 ans later. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ function NowUTCprecise: TDateTime; function FTtoDateTime (const ft: TFileTime): TDateTime; type TFT = record case integer of 0: (ft: TFileTime); 1: (i64: int64); end; var ft64: TFT; dt: TDateTime; offset: TDateTime; begin ft64.ft := ft; dt := ft64.i64; dt := dt / (1E7 * 86400); offset := EncodeDate (1601, 1, 1); Result := dt + offset; end; var ft: TFileTime; begin FPreciseFT (ft); Result := FTtoDateTime (ft); end; In the initialisation use the best available: FKernel32 := LoadLibrary ('kernel32.dll'); if FKernel32 <> 0 then begin FPreciseFT := GetProcAddress (FKernel32, 'GetSystemTimePreciseAsFileTime'); if @FPreciseFT = nil then FPreciseFT := GetProcAddress (FKernel32, 'GetSystemTimeAsFileTime'); end; ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Using NTP with a PPS source gives much better than 1 millisecond keeping: https://www.satsignal.eu/mrtg/harstad_ntp_2.html https://www.satsignal.eu/mrtg/stamsund_ntp_2.html A Raspberry Pi with a GPS/PPS hat can make an ideal local NTP server, for example: https://store.uputronics.com/index.php?route=product/product&path=64&product_id=81 (hit by the chip shortage). 73, David GM8ARV -- SatSignal Software - Quality software for you Web: https://www.satsignal.eu Email: david-taylor@... Twitter: @gm8arv
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Simon Brown
With these NMEA devices the resolution comes from the chipset. As below, the time is 09h37m52s, the milliseconds value is always returned as zero. Not all NMEA sentences are returned by every device, mine doesn’t return the timestamps.
They are easy to read – just open the COM port and read the text.
$GPGLL,5006.3037,N,00507.6798,W,093752.000,A,A*47 $GPGLL,5006.3035,N,00507.6796,W,093753.000,A,A*4A $GPGLL,5006.3032,N,00507.6792,W,093754.000,A,A*4E
From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of jdow
Sent: 11 May 2022 09:37 To: main@SDR-Radio.groups.io Subject: Re: [SDR-Radio] Future version 1.27 of the "World Map" #future
time_t timeGetTime(); That has millisecond resolution - if running with mm timer set to 1 ms. Then there is the precision (100ns) timer with motherboard dependent actual resolution. I use timeGetTime() most of the time. One must handle it's roll over, of course. With time64_to work with on 64 bit builds that's not much of a problem. It is always a relative time to when the computer boots. But that offset can be backed out if critical. On 20220511 00:10:26, Simon Brown wrote:
-- - + - + -
Please use https://forum.sdr-radio.com:4499/ when posting questions or problems.
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jdow
On 20220511 02:29:40, David J Taylor
via groups.io wrote:
On 11/05/2022 09:37, jdow wrote: The performance counter has been available for a very long time. GetSystemTimePreciseAsFileTime() is an added function that means you do not have to invent your own. Remember that this only reads the time when you call the function. This may be several ms from when the data came in on an io port buffer. There are no free lunches, unfortunately. {^_^}
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jdow
And how much time does that read operation take? And is the time mark at the start of the first byte or at the end of the last byte. And when does the program performing the read get around to performing the read. And we go down the rabbit hole of precise time on PCs running Windows. (Linux is a little better in this regard. "Real Time" Linux is even better. {^_-}
On 20220511 02:43:41, Simon Brown
wrote:
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jdow,
does the GPS receiver from Amazon really have a PPS output, that I could use without destroying the receiver?
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Simon Brown
I doubt it, it’s a USB device.
NMEA data is generated every second, but this can’t be used as PPS.
Simon Brown
From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Dirk
Sent: 11 May 2022 12:57 To: main@SDR-Radio.groups.io Subject: Re: [SDR-Radio] Future version 1.27 of the "World Map" #future
jdow, -- - + - + -
Please use https://forum.sdr-radio.com:4499/ when posting questions or problems.
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On 11/05/2022 10:43, Simon Brown wrote:
With these NMEA devices the resolution comes from the chipset. As below, the time is 09h37m52s, the milliseconds value is always returned as zero. Not all NMEA sentences are returned by every device, mine doesn’t return the timestamps.It's worse than that - the delay between the UTC second edge and the NMEA output can (and does) vary according to the length of the sentence and the amount of processing required inside the GPS device. Where possible, I recommend using the highest baud rate and the minimum number of sentences. $GPRMC is usually enough - it include time, date and location. On battery operated devices I tend to select all GNSS constellations (GPS, GLONASS and Galileo) even though it may use more battery. With a limited view, it increases the number of satellites which may be visible. 73, David -- SatSignal Software - Quality software for you Web: https://www.satsignal.eu Email: david-taylor@... Twitter: @gm8arv
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On 11/05/2022 12:33, jdow wrote:
The performance counter has been available for a very long time.Yes, and the delay is usually much more predictable on Linux systems than on Windows. The performance counter doesn't give time of day, of course, but can be useful for approximate interval measurements. PTP can overcome these limitations, at the expense of dedicated network devices. 73, David GM8ARV -- SatSignal Software - Quality software for you Web: https://www.satsignal.eu Email: david-taylor@... Twitter: @gm8arv
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Hi
as info and save a few lines of code for Simon.... and free time for dog walking.... ;-) ;-)
I always use with USB GPS on the /P location and laptop PC without internet the BktTimeSync PC APP by IZ2BKT.
It works perfectly and directly adjusts the clock and the whole PC with the GPS data on the COM.
It goes either with GPS with internet or/and COM or USB socket. Never had a TimeSync problem except that since my USB GPS is ten years old, it is not as sensitive if inside home, compared to my cell phone which receives all satellites even in the basement!
Perhaps it would be more interesting to be able to use cell phone GPS in some way, to be paired with the PC, but I wouldn't know how...
73
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EA7HGL
Greetings Simon and fellow members.
Thank you for including this function, I currently use the CLOCK program from F6CTE, and at the beginning of operating in digital I synchronize the clock with the GPS in the port (USB-Serial).
In relation to the precision, well ................... enough to not have problems with the FT8 for example.
If we want to go more than that precision, it is fine as an exercise and with the desire to reach the best accuracy, although my recommendation was born from reading that future version 1.2.7 and I thought it was a detail that would make the software even more pleasant so kindly provided by Simon.
Very grateful to both Simon and all of you for making this hobby a step beyond the commercial.
Greetings.
Antonio D. (EA7HGL). P.D: Excuse my bad english.
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jdow
Dunno - read the data on the site. That's all I know. Although I
bought one for "old times sake" given that I know what the Phase
2B satellite looks like close up and its Delta launch pad (thanks
to Hal Greenlee). I may know more before long. {^_^}
On 20220511 04:57:00, Dirk wrote:
jdow,
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