To test a navigation software, I need to simulate a NMEA-GPS log where the device has no signal. I tried it by sending a line without any position information like this:
$GPRMC,144742,V,,,,,,,,,,A*5C
$GPRMC,144743,V,,,,,,,,,,A*5D
$GPRMC,144744,V,,,,,,,,,,A*5A
But I don't know if this is the common way a gps receiver handles it.
How can I send a line to the software, the same way real hardware would do, to tell the software there is no signal from satellites?
Related
I have a GPS circuit board from china. The only information I can find on this thing is :"amoj GPS 04C www.amoj.com"
It has a serial (DB9) connection and I would like to determine how to putty into it or something.
How can I determine what the port settings that are required to access this?
Pictures below:
Photos in Dropbox
The Jupiter TU60 serial interface is 9600 8N1 by default. The only sentence it will output automatically is the flash checksum message about a second after power up. Google the datasheet for the device and it will let you know about this.
To have it output the position and other information, you must command it to do so. There is a default set of commands that are active after power up. They begin with ## and are from the protocol used by Motorola. Refer to the M12+ Users Guide and Supplement (available online) for information on how to use these commands. I have been able to enter them from Realterm. The only tricky part is calculating the checksum. You can use most hex calculators to do that.
According to the datasheet, the unit goes into survey mode automatically and after about 24 hours goes into position hold. The 1PPS and 10KHz signals are valid to less than a microsecond after a few minutes after power up and to 50nS after a day. I have compared this to another standard I have to verify this. You can use the ##Ea command to get the status of the unit and the M12+ Manual will tell you how to decode it.
Look for $GP... messages at 4800 and 9600BPS as yegorich suggest. Common NMEA messages output by GPS devices are $GPGGA, $GPVTG, $GPRMC.. If you find that data coming out, use Google to look up NMEA 0183 sentence structure and you will have what you need...
I have the same board with the Navman jupiter T Tu60 GPS 1pps 10khz GPS Module on it. I just received my sma antenna and have hooked it up. I am using 12.6V power to the centre pin.
It outputs 1pps on the led with no signal, so that is not to be trusted. Mine is labeled 1pps and 10khz underneath the pcb but these are actually swapped! I put the 10KHz output on my dso and get a 10KHz square wave 50% duty cycle signal but there is ringing on the waveform rise so I have to set the trigger level to 0.8v to get the dso to register the 10KHz frequency. I suspect this may be because the output expects a load and is not seeing one. Now, was I using ac or dc coupling?
I too am getting nothing on the serial. I tried 9600, 4800 using putty on com1 (I have a nice old motherboard) and then tried reversing rx and tx but no luck. As of now I am checking out the serial signals with the dso to see if I can work out what is happenning. I suspect that these boards are rubbish, and useful as power supplies only.
It reads 10.0000 on my hp 5328a counter and sometimes reads 9.9999. It would be nice to be able to talk to the gps to see whether it has satellite lock.
Please let me know how you get on and if you find out any further info.
Brett VK6EZ.
I successfully use WasapiLoopbackCapture() for recording audio played on system, but I'm looking for a way to record what the user would actually hear through the speakers.
I'll explain: If a certain application plays music, WASAPI Loopback shall intercept music samples, even if Windows main volume-control is set to 0, meaning: even if no sound is actually heard through audio-card's output-jack (speakers/headphone/etc).
I'd like to intercept the audio actually "reaching" the output-jack (after ALL mixers on the audio-path have "done their job").
Is this possible using NAudio (or other infrastructure)?
A code-sample or a link to a such could come in handy.
Thanks much.
No, this is not directly possible. The loopback capture provided by WASAPI is the stream of data being sent to the audio hardware. It is the hardware that controls the actual output sound, and this is where the volume level is applied to change the output signal strength. Apart from some hardware- and driver-specific options - or some interesting hardware solutions like loopback cables or external ADC - there is no direct method to get the true output data.
One option is to get the volume level from the mixer and apply it as a scaling factor on any data you receive from the loopback stream. This is not a perfect solution, but possibly the best you can do without specific hardware support.
I am trying to access an USB HID device under Ubuntu(kernel-3.0). I want to write a program which could notify me whenever an USB device is attached to the bus i.e is there any event generated whenever an USB device is plugged in which I can monitor. I have looked into DBus and HAL without any success. But I don't want linux to load its current modules(USBHID and HID) when the device is plugged in. I also want to ask if the mentioned modules are also the device drivers used for HID devices.
My sole purpose is to run a script whenever an USB device is plugged into the bus which will indirectly call the above mentioned modules.
I am writing my code in C. I am quite new to linux. So it would be of great help if anyone could point me in the right direction.
Thanks..
The UDisks deamon will send the D-Bus signal "DeviceAdded" when a USB drive is inserted, and probably another "DeviceAdded" for each partition on the drive. If you have automount you would also get a "DeviceChanged" signal when the partition(s) are mounted. You can then query the UDisks interface, as well as individual devices about their properties, for example. You can find more info on the UDisks interface here: http://hal.freedesktop.org/docs/udisks/UDisks.html
One way to get more familiar with what goes on with block devices (or whatever) on D-Bus, is to install and use D-Feet to inspect the bus. UDisks appear on the System bus. You can see what is there and inspect the properties for individual devices as well as the UDisks interface itself.
Another way, which would also allow you to see what signals are transmitted on the bus, is to run dbus-monitor from the command line.
We have developed an application on Windows.net mobile framework and it is used on a Windows 6.5 Smartphone. for our location based application. Our application is real time and tracks our employees. We are finding that the device loses its GPS signal.
Has anyone managed to restart the GPS receiver so that it starts giving the GPS signal again. I would be ever so gratefull if someone can help. We are using GeoFramework2.0 to deliver the geographic information that you need.
Regards
Sandy
The GPS is "shut down" when no application is using it. Just close your handles and re-open them.
If the GPS on your device is part of the WWAN radio (i.e. cellular phone) it may get put in to a low power state rather than being actually shut off. In that case, you can try restarting the radio.
If that doesn't work, some GPS's will allow you to send proprietary commands to them to force a reset or clear the memory. These commands are not standard and will differ significantly by manufacturer. If you have a SiRF GPS, take a look at the SiRF Binary Protocol Reference.
im trying to read the current position of GPS Device...using N95 from Nokia.
I read tht i will need my device to return the NMEA lines to the serialport and then i will parse/split it to get things I want but all along I dont know what to write to the serialport to make device return the NMEA ?
Like There are other commands of AT for messaging etc...Is there any specific command to send to serialport to get NMEA ???
I found this site site which seems to guide you through everything you need to do.
I am not sure how it works in the N95, but in my HTC phone you cannot send commands to the GPS device to have it behave in a certain manner. Once I am connected to the serial port that the GPS device uses I can read a stream of data coming from it, which happens to be NMEA data. There is no way that I have found to send commands to the device to tell it how to behave.
I haven't used that specific GPS device before, but for mine, I just have to open the port and I start receiving the NMEA data immediately.
I have an N82, and as far as I know it doesn't speak NMEA directly. I use a script from this page - specifically one the titled "# Turn your S60 phone with an internal GPS (eg your N95) into a Bluetooth GPS" - to get NMEA strings.
Ahh oki so I need to run some script.Oki I think i should buy a specific GPS Device for it.
Which device will do my job in cheapest manner ?
I've never worked specifically with the N95, but most GPS devices will just start spitting out NMEA as soon as they're powered up, regardless of whether or not they have a lock. I don't know how the N95 is designed, but I'll bet it probably wasn't designed to give you access to the raw NMEA data from the GPS. You'll probably need some pretty fancy trickery to get it to do that.
If you don't need to use the N95, you might find it easier to just get a GPS module and use that instead. I've always purchased mine from SparkFun. They have some good evaluation boards boards and tutorials to help you get started.
A great way of doing this in Java ME is to use JSR 179: the Location API. Your app needs to create an implementation of LocationListener, then set it on the default LocationProvider. When your listener's locationUpdated method gets called, call:
location.getExtraInfo("application/X-jsr179-location-nmea");
This will provide access to the NMEA sentences.
You can send this over a serial port by using the Java ME commports mechanism (use:
System.getProperty("microedition.commports");
as described here).
Hope this helps,
funkybro