* Posts by Andrew Ansell

9 posts • joined 21 Jul 2015

Brexit? Cutting the old-school ties would do more for Brit tech world

Andrew Ansell

Re: Prat

The word "Oxford" appears once on the article. As part of the phrase "Oxford and Cambridge".

What a prat. Sitting there not reading a story properly and then somehow blaming someone else for his apparent inability to tell the difference between Oxford and Oxbridge, the commonly used abbreviation for Oxford and Cambridge.

US work visas for international tech talent? 'If Donald Trump is elected all bets are off'

Andrew Ansell

Re: Good for competition?

How are US employment laws worse than the UK?

Maternity/paternity leave:

UK 52 weeks split however you want between both parents, Several months of it paid and a slowly decreasing amount.

USA 6 weeks unpaid for the mother. (12 weeks each parent with some pay in California)

Job security:

UK any professional job is will have a 4 week or more bilateral notice period. There is a legal minimum redundancy payment.

USA your notice period is the time it takes to escort you to the door. No required payoff for laying someone off. (If on an H-1B this gives you 2 weeks to get out the country)

Time off:

UK professional jobs will typically have 25 days time off per year. The legal minimum is 20 days. Employers will encourage people to use them up.

US no legal minimum. Typically ~20 offered for silicon valley tech companies however some companies strongly discourage people to use them.

Sick pay:

UK if you are sick you don't come in to the office. This does not come off your holiday allowance.

USA if you are sick you either use your time off or come in and infect your coworkers.

Trump's new thought bubble: Make Apple manufacture in the USA

Andrew Ansell

"In reality, how credible is Trump? Is all this bluster and American exceptionalism what voters are actually looking for?"

Depressingly yes.

Yes, for some he is a laughing stock. But for the fox news watching, everything is someone else's fault, Obama is a Muslim traitor to the USA crowd this is exactly what they want to hear.

And remember he isn't playing to the population as a whole, he's only got to convince republican supporters right now.

If he gets the republican nomination a lot of republicans will vote for him even if they think he's crazy because the alternative is a democrat winning.

US politics: where they put the stories that are too absurd for reality TV.

GPS, you've gone too far this time

Andrew Ansell

Re: It isn't that

"Presumably the explanation lies in the Doppler measurements. These are an additional source of raw data and so it is much less surprising to be told that they can be used to improve the accuracy of the positional ones. Is that it?"


A GPS receiver measures the frequency of the signals from the satellites. This will be offset from the theoretical frequency by the doppler caused by the relative velocities of the satellite and the receiver.

After subtracting the satellites orbital motion and the earths rotation you are left with the effect of the receivers motion.

This allows you to calculate velocity in a method that is completely independent of the position calculation (well ok you need to know your location to subtract the earths motion but a 100m error in that doesn't have much impact).

For short term relative motion integrating this velocity is more accurate than position delta. It's not much use for long term position, as with any integral of a noisy value it will drift over time. And it's useless for absolute position.

Andrew Ansell

Re: Walking the dog

I forgot to add - this is all assuming GPS errors are random.

They aren't.

If you leave the receiver stationary the average difference in position 1 second to the next is far smaller than the average difference 1 hour to the next. A lot of the errors are caused by atmospheric effects and they don't change rapidly.

However if you are moving and a tree or building blocks the line of sight to an SV then you can get a big instantaneous position jump. These are fairly obvious to detect because the position may say you just traveled 10m in a second but the reported velocity won't have a corresponding jump. Unfortunately detecting them doesn't tell you which of the two positions was correct.

Andrew Ansell

Re: It isn't that

Having also worked on GPS systems (including I think some of the receivers Charles worked on) and now working for a company that bases it's core business on giving accurate distance measurements from GPS I'd add that this is hardly original or shocking news.

Our products don't look at the difference in location, we integrate velocity to give distance and have been doing so for years. As long as you don't have high accelerations it's trivial and works really well on any receiver. With heavy acceleration you have to start worrying about which receiver you are using.

US Presidential race becomes Wi-Fi password snark battle

Andrew Ansell

"Opponents counter that Indian companies enjoy an unfair advantage because they can bring their own staff to the United States on H-1Bs and therefore enjoy lower costs."

For a technical worker internal transfers to the US office are normally L-1 visas. They are easier to obtain than H-1B since you don't need to show you can't hire an american to do the work.

And on that note - In order to hire someone on an H-1B you must show that you couldn't find an american to do the job and that you are paying a competitive wage. If republicans are complaining that the visas are allowing cheap foreign workers to take american jobs then they don't need to scrap the system, they need to enforce the existing rules.

Caption this: WIN a 6TB Western Digital Black hard drive with El Reg

Andrew Ansell

Despite being late and over budget the new government spy cameras turned out not to be as discreet as had been hoped.

SpaceX's blast shock delays world's MOST POWERFUL ROCKET

Andrew Ansell

Re: Re-Use

The space shuttles and their solid boosters were re-used. Yes they had a couple of failures but those weren't due to the re-use of the parts.

Of course they are also a good example of how re-use didn't provide the expected cost savings.

Biting the hand that feeds IT © 1998–2019