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gebi /
Created March 26, 2021 19:30 — forked from veproza/
Getting u-blox MAX-7C GPS to work with Assisted A-GPS

Getting u-blox MAX-7C GPS to work with Assisted A-GPS

So you got your u-blox GPS and wired it up only to look at it struggling to get a valid fix? Under less than ideal conditions, it can take a better part of half an hour. That's because unlike your smartphone GPS, it doesn't have the luxury of having downloaded all the auxiliary navigation data (almanacs and the lot) out-of-band, via fast mobile connection. Instead it relies on the satellite's signal itself, which is being transmitted to you at meager 50 bits per second (I'm not missing "kilo" there, it's three orders of magnitude slower than your 2G GPRS connection).

Luckily, the u-blox receivers are fitted with what the company calls "AssistNow" capability and it does exactly the same thing your iPhone does - feeds the GPS with pre-downloaded almanacs, speeding up the acquisition process to mere seconds.

In principle, the process looks easy enough - we just need to download the data, and then push them to the receiver. Sadly, the AssistNow documentat

gebi /
Created March 5, 2021 14:59 — forked from bradfitz/
# Brad's el-ghetto do-our-storage-stacks-lie?-script
sub usage {
die <<'END';
Usage: -s <server[:port]> verify <file> -s <server[:port]> create <file> <size_in_MB> -l [port]
gebi / psql_internals_cheatsheet.sql
Created March 5, 2021 14:57 — forked from azet/psql_internals_cheatsheet.sql
PostgreSQL internals SQL collection
View psql_internals_cheatsheet.sql
# long running queries:
now() - pg_stat_activity.query_start AS duration,
FROM pg_stat_activity
WHERE (now() - pg_stat_activity.query_start) > interval '5 minutes';
## active queries and killing them:
gebi / out.b
Created November 3, 2010 16:13
convert text to brainfuck
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gebi / gitconfig
Created November 18, 2016 16:30
Git config
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a = annex
sf = svn fetch
sr = svn rebase
sd = svn dcommit
s = status
st = status
sb = show-branch
b = branch
c = clone
gebi / google-chrome-anon
Created November 8, 2016 16:54
Start temporary google chrome instance
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tmp_=$(mktemp -d --tmpdir google-chrome-anon-XXXXXXXXXX)
echo "private dir: " $tmp_
trap "{ rm -rf /tmp/$(basename $tmp_); exit 255; }" EXIT
nice -n5 google-chrome --user-data-dir=$tmp_
gebi / json_utils.go
Created July 30, 2013 19:52
http utils for protobuf/json
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package main
import (
gebi / csv-test.go
Last active December 19, 2015 16:38
csv test progs in various languages
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package main
import (
gebi / static_mem_test.c
Last active December 16, 2015 18:59
Short example program to show linux memory allocation behaviour (memory is only allocated on first access, in this example program after you press enter) Test with: gcc -O0 -Wall static_mem_test.c -o static_mem_test && /usr/bin/time --verbose ./static_mem_test
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#include <unistd.h>
#define WRITE(Str) write(1, Str, sizeof(Str))
int main()
char in;
int i;
View nextprime.go
package main
import (