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GPS receiver/simulator using bladeRF

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GPS receiver/simulator using bladeRF

Posted: Sun Feb 23, 2014 8:16 pm
by taro
Hi everyone,

I’m developing a GPS receiver/simulator using bladeRF. As far as I can see, the current firmware and fpga are improved with respect to packet losses.

At this moment, real-time GPS positioning using bladeRF worked well :P
Here is the demonstration video on YouTube.
http://www.youtube.com/watch?v=uf2vatqek_o

However, there are still few packet losses if we set sampling rate as 40 Msps. The bladeRF is of course connected via USB 3.0 port. In addition, there is also a large DC bias.

Further, Tx at 1.5GHz doesn't work well. For example, I put following commands using bladeRF-cli.exe, but bladeRF-cli.exe has crashed after “tx start”.

Set frequency 1.57542G
Set samplerate 8M
rx config file=test.bin n=8M
rx start
tx config file=test.bin
tx start

Please let me know if anyone has any solutions.

Thank you.
Taro

Re: GPS receiver/simulator using bladeRF

Posted: Sun Feb 23, 2014 9:40 pm
by drmpeg
From your video, it looks like you're only using Windows, so this may not help entirely. In Linux, you can use osmocom_fft to eliminate the DC offset.

osmocom_fft -s 8000000 -f 429000000 --dc-offset-mode=0

This starts osmocom_fft with a slider to adjust the DC offset. With some careful tuning, you can just about eliminate the DC offset.

Image

The bladeRF remembers the DC offset correction, so once you've tuned it for a given frequency and RX gains, it will be good for other applications.

Ron

Re: GPS receiver/simulator using bladeRF

Posted: Mon Feb 24, 2014 4:53 am
by taro
Ron and Jon,
Thank you for your quick reply.

DC offset
I’ll try to call the “bladerf_set_correction()” in my software to correct IQ imbalance.

Sample rate issue
In my program, the samples are stored in memory to process in real-time instead of saving samples to disk. I tried to use the 32-bit counter mode. It was very useful to check the sample losses. In both win7 64bit and Ubuntu 13.10 64bit environments, the counter value was continuous except for the first 1ms (but I think it’s not a big problem…) I attached the figure which shows the difference between the counter value.

Image

I think I will have to evaluate the more long-term effects. Anyway, thank you for nice information.

Tx problem
I downloaded and built the latest libbladeRF code from git in the both windows and linux environment. However, “set tx frequency” didn’t work at any frequency…I attached the screen shot of the bladerf-cli. Does the “set tx frequency” work correctly in the latest source code?

Image

Thank you,
Taro

Re: GPS receiver/simulator using bladeRF

Posted: Wed Feb 26, 2014 7:57 am
by taro
Thanks for every help.

Today, I saved the bladeRF-cli log when I was setting the TX frequency. I tried to do “print frequency” before setting, but it worked well. After that, I could not change to any frequency.

I’m sure that the source code is up-to-date.
I might borrow another bladeRF board in a few days, and if so, I will try to check TX tuning using another board.

Code: Select all

ubuntu@ubuntu:~/bladeRF/host/build/output$ sudo ./bladeRF-cli -i -v verbose
[VERBOSE] Using libusb version: 1.0.16.10774
[VERBOSE] Non-bladeRF device found: VID 8087, PID 0024
[VERBOSE] Non-bladeRF device found: VID 1d6b, PID 0002
[VERBOSE] Non-bladeRF device found: VID 1d6b, PID 0003
[VERBOSE] Non-bladeRF device found: VID 1d6b, PID 0002
[VERBOSE] Non-bladeRF device found: VID 058f, PID 6362
[VERBOSE] Non-bladeRF device found: VID 04f2, PID 1060
[VERBOSE] Non-bladeRF device found: VID 8087, PID 0024
[VERBOSE] Non-bladeRF device found: VID 1d6b, PID 0002
[VERBOSE] Found a bladeRF (based upon VID/PID)
[VERBOSE] Claimed all inferfaces successfully
[VERBOSE] Change to alternate interface 0
[VERBOSE] Change to alternate interface 1
[VERBOSE] Changed into RF link mode: LIBUSB_SUCCESS / LIBUSB_TRANSFER_COMPLETED
[VERBOSE] Peripheral access: [ 0x4e, 0x81, 0x0c, 0xff ]
[VERBOSE] Peripheral access: [ 0x4e, 0x81, 0x0d, 0xff ]
[VERBOSE] Peripheral access: [ 0x4e, 0x81, 0x0e, 0xff ]
[VERBOSE] Peripheral access: [ 0x4e, 0x81, 0x0f, 0xff ]
[DEBUG] Raw FPGA Version: 0x00030000
[DEBUG] bladerf_open_with_devinfo: fw=v1.6.1-git-b7e6642 serial=b6c56fbd99eab1a80445117597964bcd trim=0xaaad fpga_size=40
[VERBOSE] Peripheral access: [ 0x4e, 0x81, 0x00, 0xff ]
[VERBOSE] Peripheral access: [ 0x4e, 0x81, 0x01, 0xff ]
[VERBOSE] Peripheral access: [ 0x4e, 0x81, 0x02, 0xff ]
[VERBOSE] Peripheral access: [ 0x4e, 0x81, 0x03, 0xff ]
bladeRF> print frequency tx
[VERBOSE] Peripheral access: [ 0x4e, 0x91, 0x10, 0xff ]
[VERBOSE] lusb_lms_read: 0x10 0x34
[VERBOSE] Peripheral access: [ 0x4e, 0x91, 0x11, 0xff ]
[VERBOSE] lusb_lms_read: 0x11 0x15
[VERBOSE] Peripheral access: [ 0x4e, 0x91, 0x12, 0xff ]
[VERBOSE] lusb_lms_read: 0x12 0x55
[VERBOSE] Peripheral access: [ 0x4e, 0x91, 0x13, 0xff ]
[VERBOSE] lusb_lms_read: 0x13 0x55
[VERBOSE] Peripheral access: [ 0x4e, 0x91, 0x15, 0xff ]
[VERBOSE] lusb_lms_read: 0x15 0x95

  TX Frequency: 1000000000Hz

bladeRF> set frequency tx 1.57542G

[VERBOSE] ---- Frequency ----
[VERBOSE]   x        : 4
[VERBOSE]   nint     : 164
[VERBOSE]   nfrac    : 891290
[VERBOSE]   freqsel  : 0x35
[VERBOSE]   reference: 38400000
[VERBOSE]   freq     : 1575420000
[VERBOSE] Peripheral access: [ 0x4e, 0x91, 0x09, 0xff ]
[VERBOSE] lusb_lms_read: 0x09 0x40
[VERBOSE] lusb_lms_write: 0x09 0x45
[VERBOSE] Peripheral access: [ 0x4e, 0x51, 0x09, 0x45 ]
[VERBOSE] Peripheral access: [ 0x4e, 0x91, 0x15, 0xff ]
[VERBOSE] lusb_lms_read: 0x15 0x95
[VERBOSE] Peripheral access: [ 0x4e, 0x91, 0x08, 0xff ]
[VERBOSE] lusb_lms_read: 0x08 0x00
[VERBOSE] Peripheral access: [ 0x4e, 0x91, 0x46, 0xff ]
[VERBOSE] lusb_lms_read: 0x46 0x00
[VERBOSE] lusb_lms_write: 0x15 0xd6
[VERBOSE] Peripheral access: [ 0x4e, 0x51, 0x15, 0xd6 ]
[VERBOSE] lusb_lms_write: 0x10 0x52
[VERBOSE] Peripheral access: [ 0x4e, 0x51, 0x10, 0x52 ]
[VERBOSE] lusb_lms_write: 0x11 0x0d
[VERBOSE] Peripheral access: [ 0x4e, 0x51, 0x11, 0x0d ]
[VERBOSE] lusb_lms_write: 0x12 0x99
[VERBOSE] Peripheral access: [ 0x4e, 0x51, 0x12, 0x99 ]
[VERBOSE] lusb_lms_write: 0x13 0x9a
[VERBOSE] Peripheral access: [ 0x4e, 0x51, 0x13, 0x9a ]
[VERBOSE] Peripheral access: [ 0x4e, 0x91, 0x16, 0xff ]
[VERBOSE] lusb_lms_read: 0x16 0x8c
[VERBOSE] lusb_lms_write: 0x16 0x8c
[VERBOSE] Peripheral access: [ 0x4e, 0x51, 0x16, 0x8c ]
[VERBOSE] Peripheral access: [ 0x4e, 0x91, 0x17, 0xff ]
[VERBOSE] lusb_lms_read: 0x17 0xe3
[VERBOSE] lusb_lms_write: 0x17 0xe3
[VERBOSE] Peripheral access: [ 0x4e, 0x51, 0x17, 0xe3 ]
[VERBOSE] Peripheral access: [ 0x4e, 0x91, 0x18, 0xff ]
[VERBOSE] lusb_lms_read: 0x18 0x40
[VERBOSE] lusb_lms_write: 0x18 0x40
[VERBOSE] Peripheral access: [ 0x4e, 0x51, 0x18, 0x40 ]
[VERBOSE] Peripheral access: [ 0x4e, 0x91, 0x19, 0xff ]
[VERBOSE] lusb_lms_read: 0x19 0xa0
[VERBOSE] lusb_lms_write: 0x19 0xa0
[VERBOSE] Peripheral access: [ 0x4e, 0x51, 0x19, 0xa0 ]
[VERBOSE] Peripheral access: [ 0x4e, 0x91, 0x1a, 0xff ]
[VERBOSE] lusb_lms_read: 0x1a 0x43
[VERBOSE] Too low: 32 -> 16
[VERBOSE] lusb_lms_write: 0x19 0x90
[VERBOSE] Peripheral access: [ 0x4e, 0x51, 0x19, 0x90 ]
[VERBOSE] Peripheral access: [ 0x4e, 0x91, 0x1a, 0xff ]
[VERBOSE] lusb_lms_read: 0x1a 0x43
[VERBOSE] Too low: 16 -> 8
[VERBOSE] lusb_lms_write: 0x19 0x88
[VERBOSE] Peripheral access: [ 0x4e, 0x51, 0x19, 0x88 ]
[VERBOSE] Peripheral access: [ 0x4e, 0x91, 0x1a, 0xff ]
[VERBOSE] lusb_lms_read: 0x1a 0x43
[VERBOSE] Too low: 8 -> 4
[VERBOSE] lusb_lms_write: 0x19 0x84
[VERBOSE] Peripheral access: [ 0x4e, 0x51, 0x19, 0x84 ]
[VERBOSE] Peripheral access: [ 0x4e, 0x91, 0x1a, 0xff ]
[VERBOSE] lusb_lms_read: 0x1a 0x43
[VERBOSE] Too low: 4 -> 2
[VERBOSE] lusb_lms_write: 0x19 0x82
[VERBOSE] Peripheral access: [ 0x4e, 0x51, 0x19, 0x82 ]
[VERBOSE] Peripheral access: [ 0x4e, 0x91, 0x1a, 0xff ]
[VERBOSE] lusb_lms_read: 0x1a 0x43
[VERBOSE] Too low: 2 -> 1
[VERBOSE] lusb_lms_write: 0x19 0x81
[VERBOSE] Peripheral access: [ 0x4e, 0x51, 0x19, 0x81 ]
[VERBOSE] Peripheral access: [ 0x4e, 0x91, 0x1a, 0xff ]
[VERBOSE] lusb_lms_read: 0x1a 0x43
[VERBOSE] Too low: 1 -> 1
[DEBUG] VTUNE is not locked at the end of initial loop
[VERBOSE] Peripheral access: [ 0x4e, 0x91, 0x09, 0xff ]
[VERBOSE] lusb_lms_read: 0x09 0x45
[VERBOSE] lusb_lms_write: 0x09 0x40
[VERBOSE] Peripheral access: [ 0x4e, 0x51, 0x09, 0x40 ]

Error: An unexpected error occurred
bladeRF> set frequency tx 429M

[VERBOSE] ---- Frequency ----
[VERBOSE]   x        : 16
[VERBOSE]   nint     : 178
[VERBOSE]   nfrac    : 6291456
[VERBOSE]   freqsel  : 0x3f
[VERBOSE]   reference: 38400000
[VERBOSE]   freq     : 429000000
[VERBOSE] Peripheral access: [ 0x4e, 0x91, 0x09, 0xff ]
[VERBOSE] lusb_lms_read: 0x09 0x40
[VERBOSE] lusb_lms_write: 0x09 0x45
[VERBOSE] Peripheral access: [ 0x4e, 0x51, 0x09, 0x45 ]
[VERBOSE] Peripheral access: [ 0x4e, 0x91, 0x15, 0xff ]
[VERBOSE] lusb_lms_read: 0x15 0xd6
[VERBOSE] Peripheral access: [ 0x4e, 0x91, 0x08, 0xff ]
[VERBOSE] lusb_lms_read: 0x08 0x00
[VERBOSE] Peripheral access: [ 0x4e, 0x91, 0x46, 0xff ]
[VERBOSE] lusb_lms_read: 0x46 0x00
[VERBOSE] lusb_lms_write: 0x15 0xfd
[VERBOSE] Peripheral access: [ 0x4e, 0x51, 0x15, 0xfd ]
[VERBOSE] lusb_lms_write: 0x10 0x59
[VERBOSE] Peripheral access: [ 0x4e, 0x51, 0x10, 0x59 ]
[VERBOSE] lusb_lms_write: 0x11 0x60
[VERBOSE] Peripheral access: [ 0x4e, 0x51, 0x11, 0x60 ]
[VERBOSE] lusb_lms_write: 0x12 0x00
[VERBOSE] Peripheral access: [ 0x4e, 0x51, 0x12, 0x00 ]
[VERBOSE] lusb_lms_write: 0x13 0x00
[VERBOSE] Peripheral access: [ 0x4e, 0x51, 0x13, 0x00 ]
[VERBOSE] Peripheral access: [ 0x4e, 0x91, 0x16, 0xff ]
[VERBOSE] lusb_lms_read: 0x16 0x8c
[VERBOSE] lusb_lms_write: 0x16 0x8c
[VERBOSE] Peripheral access: [ 0x4e, 0x51, 0x16, 0x8c ]
[VERBOSE] Peripheral access: [ 0x4e, 0x91, 0x17, 0xff ]
[VERBOSE] lusb_lms_read: 0x17 0xe3
[VERBOSE] lusb_lms_write: 0x17 0xe3
[VERBOSE] Peripheral access: [ 0x4e, 0x51, 0x17, 0xe3 ]
[VERBOSE] Peripheral access: [ 0x4e, 0x91, 0x18, 0xff ]
[VERBOSE] lusb_lms_read: 0x18 0x40
[VERBOSE] lusb_lms_write: 0x18 0x40
[VERBOSE] Peripheral access: [ 0x4e, 0x51, 0x18, 0x40 ]
[VERBOSE] Peripheral access: [ 0x4e, 0x91, 0x19, 0xff ]
[VERBOSE] lusb_lms_read: 0x19 0x81
[VERBOSE] lusb_lms_write: 0x19 0xa0
[VERBOSE] Peripheral access: [ 0x4e, 0x51, 0x19, 0xa0 ]
[VERBOSE] Peripheral access: [ 0x4e, 0x91, 0x1a, 0xff ]
[VERBOSE] lusb_lms_read: 0x1a 0x43
[VERBOSE] Too low: 32 -> 16
[VERBOSE] lusb_lms_write: 0x19 0x90
[VERBOSE] Peripheral access: [ 0x4e, 0x51, 0x19, 0x90 ]
[VERBOSE] Peripheral access: [ 0x4e, 0x91, 0x1a, 0xff ]
[VERBOSE] lusb_lms_read: 0x1a 0x43
[VERBOSE] Too low: 16 -> 8
[VERBOSE] lusb_lms_write: 0x19 0x88
[VERBOSE] Peripheral access: [ 0x4e, 0x51, 0x19, 0x88 ]
[VERBOSE] Peripheral access: [ 0x4e, 0x91, 0x1a, 0xff ]
[VERBOSE] lusb_lms_read: 0x1a 0x43
[VERBOSE] Too low: 8 -> 4
[VERBOSE] lusb_lms_write: 0x19 0x84
[VERBOSE] Peripheral access: [ 0x4e, 0x51, 0x19, 0x84 ]
[VERBOSE] Peripheral access: [ 0x4e, 0x91, 0x1a, 0xff ]
[VERBOSE] lusb_lms_read: 0x1a 0x43
[VERBOSE] Too low: 4 -> 2
[VERBOSE] lusb_lms_write: 0x19 0x82
[VERBOSE] Peripheral access: [ 0x4e, 0x51, 0x19, 0x82 ]
[VERBOSE] Peripheral access: [ 0x4e, 0x91, 0x1a, 0xff ]
[VERBOSE] lusb_lms_read: 0x1a 0x43
[VERBOSE] Too low: 2 -> 1
[VERBOSE] lusb_lms_write: 0x19 0x81
[VERBOSE] Peripheral access: [ 0x4e, 0x51, 0x19, 0x81 ]
[VERBOSE] Peripheral access: [ 0x4e, 0x91, 0x1a, 0xff ]
[VERBOSE] lusb_lms_read: 0x1a 0x43
[VERBOSE] Too low: 1 -> 1
[DEBUG] VTUNE is not locked at the end of initial loop
[VERBOSE] Peripheral access: [ 0x4e, 0x91, 0x09, 0xff ]
[VERBOSE] lusb_lms_read: 0x09 0x45
[VERBOSE] lusb_lms_write: 0x09 0x40
[VERBOSE] Peripheral access: [ 0x4e, 0x51, 0x09, 0x40 ]

Error: An unexpected error occurred
bladeRF>
Taro
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