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Chupacabra kirjutas: ↑22 Aug, 2024 11:12

kmeesk kirjutas: ↑22 Aug, 2024 11:02
Võre vastu võib aidata ka see, et tuleb ühe asemel kaks drooni. Esimene teeb võresse augu ja teine siseneb augu kaudu.

Nii täpselt droonid täna ei lenda.

kmeesk kirjutas: ↑22 Aug, 2024 12:13
Ma arvan, et droonid lendavad üsna täpselt, kui nad omavahel paari panna, et tagumine jälgib ees lendava trajektoori. Ma arvan, et pommi käivitusmehhanismi saab ka nii teha, et see plahvataks, siis kui ta võiks olla sihtmärgi juures kasutades erinevaid andureid selleks.

Chupacabra kirjutas: ↑22 Aug, 2024 12:22

kmeesk kirjutas: ↑22 Aug, 2024 12:13
Ma arvan, et droonid lendavad üsna täpselt, kui nad omavahel paari panna, et tagumine jälgib ees lendava trajektoori. Ma arvan, et pommi käivitusmehhanismi saab ka nii teha, et see plahvataks, siis kui ta võiks olla sihtmärgi juures kasutades erinevaid andureid selleks.

Kõike saab teha aga tänaseni ei ole selliseid lahendusi vaja olnud. Kui need võred muutuvad nii suureks probleemiks, küll siis leitakse ka lahendused.

MadMan kirjutas: ↑19 Sept, 2024 14:43 Perun lahkab süsteeme, mis UA sõjas on kaotanud oma efektiivsuse.
Excalibur - toimis kuni 2023 lõpuni, segamise tõttu langes tabamuste tõenäosus 1 tabamus 20 lasu kohta.
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Blunting Excalibur’s edge
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A general rule of thumb regarding GPS is that the faster the bit-per-second rate of the signal, the more precise the GPS receiver will be in determining position. C/A-code has a sequence of 1,023 bits-per-second transmitted at a rate of 1,230,000 bits-per-second meaning the C/A-code’s sequence repeats each millisecond. P-code is transmitted on the L1 and L2 signals but a key difference between P-code and C/A-code is that the former is transmitted at a rate of 12,300,000 bits-per-second; ten times faster than the latter. The higher bit-per-second rate gives more precise timelag measurement, translating into a more precise range measurement, and since the P-code is transmitted on both L1 and L2, it allows the time delay of the ionosphere to be removed. For example, C/A-code may give about 4 m of accuracy, says Douglas Loverro, President of Loverro Consulting and former Deputy Assistant Secretary of Defence for space policy in the US Department of Defense (DOD). According to Loverro, who was a key architect of the GPS system, “The P-code lets you get down to under three metres (ten feet) of accuracy.”

P-code is secured using encryption to avoid it being spoofed or jammed with the encrypted signal known as P(Y)-code. “P(Y)-code was designed with encryption to avoid the signal being spoofed and to avoid other people using the P signal who should not be,” Loverro explained.

Two things need to happen to allow a GPS receiver to use P(Y)-code. The moment a receiver is switched on, it must first acquire the C/A-code. Once this is done, it can then begin to receive the P(Y)-code. This can be a potential disadvantage if C/A-code signals are being jammed locally, Loverro
noted. Any GPS receiver in range of the jamming will simply be unable to receive the C/A-code, let alone the P(Y)-code. It is noteworthy that some GPS receivers currently do have the ability to receive P(Y)-code without obtaining the C/A-code first.

To use the encrypted P(Y) code, users need to have a decryption key they can load into their GPS receivers, Loverro added. The key decrypts the incoming P(Y)-code allowing the receiver to use that signal. The US DOD provides the authorisation for users to receive the P(Y) keys and to load
them into their devices. Given the jamming that the Ukrainian military has suffered when it has used GPS-guided weaponry, it is unclear if they were provided with a P(Y)-code capability in these weapons’ GPS receivers. This is perhaps not surprising. Access to P(Y)-code is reserved for the US’s NATO Allies on a case-by-case basis, according to Loverro. The DOD is understandably concerned about the security aspects of sharing P(Y) codes with Ukraine lest decryption keys fall into Russian hands P(Y)-code shortcomings are being addressed with the advent of M-Code, which is yet to enter service, but could prove to be a potent enhancement.

Firstly, M-Code is transmitted using L1 and L2 signals. The signal will be transmitted with more power to provide added resistance to jamming. It also does not need to connect with C/A-code before being used. M-Code also ‘plays nice’ with the existing C/A- and P(Y)-codes and, like P(Y)-code, M-Code is encrypted.

The good news is that US and allied militaries are now embracing M-Code. The bad news is the Ukrainian military is unlikely to be gain access for similar reasons to the P(Y)-code quandary. Nonetheless, Russian EW cadres may soon find out that switching on their GPS jammers maybe akin to signing their own death warrants. The Defence Post reported in May that Scientific Applications and Research Associates (SARA) received a contract worth USD23.6 million for a JDAM Home-On Jam (HOJ) capability. Specifically, this will be an augmentation to the GPS receivers used by the GBU-62 JDAM-ER (extended range) variant of the guidance kit.

Details on how the HOJ capability will work are scant, but it is possible that the GPS receiver will be programmed to recognise an abnormal GPS signal. As noted above, GPS jamming typically relies on using a much stronger fake PNT signal to wash out the relatively weak true signal.

Should the receiver detect a jamming transmission, it will ascertain the signal’s bearing. The munition will guide itself along the bearing until it reaches the signal’s point of origin, announcing its arrival with a bang. This tactic is akin to that used against hostile ground-based air surveillance and fire control/ground-controlled interception radars by anti-radiation missiles. While Kyiv is unlikely to receive P(Y)-code keys, or even access to M-Code any time soon, Ukraine’s military has been supplied with JDAM-ER weapons. Reports regarding the HOJ capability say this will be made available to Ukraine, with the work being completed by October 2025. While this date appears some time away, it may be possible that upgraded JDAM-ERs will be drip-fed as built into the Ukrainian military. Looking further ahead, perhaps similar improvements may be added to HIMARS and Excalibur in the future. Either way, such improved weapons will give Russian EW cadres a Hobson’s choice: to switch on their jammers to protect their troops and assets against GPS-guided weapons? Or switch off their jammers and save themselves but possibly doom your comrades? How Russian forces will resolve this dilemma remains to be seen.

https://euro-sd.com/wp-content/uploads/ ... 7_2024.pdf

There was no information provided on how target coordinates and elevations were collected by reconnaissance drones that may be using other coordinate systems (like older UTMs often used by ground troops rather than the WGS84 coordinate system used by GPS), nor how the height above mean sea level was determined, if used at all.

It’s possible that in addition to GPS interference, the initial or target coordinates were inaccurate to begin with, which needs to include not only latitude and longitude but also target elevation above mean sea level (MSL), rendering the guidance less effective. In the case of artillery and HIMARS strikes, it’s common for Ukrainian troops to spot the target through drones or reconnaissance units, where a room of error can theoretically exist due to Russian EW systems in operation.

It is also not known how Ukrainian drones derive target elevation without finding that information using a laser or radar altimeter and comparing that to the drone’s altitude (which may or may not be accounted for or known) to calculate the MSL of the object in question. Target elevation in weapons employment is critical to minimize weapons impact errors and is nearly as important as accurate latitude and longitude coordinates.

Since certain weapons rely on GPS time-stamps and onboard 3-D positional calculations based on this in mid-flight to adjust their courses – as in the case of some drones – Russian troops can theoretically “spoof” the GPS modules by feeding it false GPS satellite time-stamps, which would also throw the weapons off course – a tactic Ukraine has used against Russian drones to some effect.

Another bit of information not provided is what level of inaccuracy was introduced and what was required to be considered a hit. This depends on the type of target and the type of weapon in use along with a myriad of factors not mentioned, or perhaps even considered, by either the Ukrainian sources or the NYT and Washington Post articles.

While it’s a known fact that Russia has developed advanced EW capabilities, how exactly it managed to throw GPS-aided munitions off course remains unclear based on the NYT and Washington Post articles.

kaur3 kirjutas: ↑25 Sept, 2024 16:51 Ukraina sõja eelsest analüütilisest põrumisest.
https://www.csis.org/analysis/russia-uk ... ic-failure

Woodward reports that in the lead-up to Russia’s invasion, the US had obtained a treasure trove of intelligence, which showed “conclusively” in October 2021 that Putin had plans to invade Ukraine with 175,000 troops.

“It was an astonishing intelligence coup from the crown jewels of US intelligence, including a human source inside the Kremlin,” Woodward reports. Human sources are among the most sensitive in the intelligence world.

“It was as if they had secretly entered the enemy commander’s tent and were hunched over the maps, examining the number and movement of brigades and the entire planned sequence on the multifront invasion,” Woodward writes.

While Biden and his advisers agreed the plan was “dead serious,” it was still hard for them — and their allies — to believe it.

“This is what Putin plans to do,” CIA Director Bill Burns said to Biden, according to Woodward.

“This would be so crazy,” Biden responded.

“Jesus Christ!” Biden said. “Now I’ve got to deal with Russia swallowing Ukraine?”

Biden confronted Putin with the intelligence twice in December 2021, first in a video conference and then in what Woodward describes as a “hot 50-minute call” that became so heated that at one point that Putin “raised the risk of nuclear war in a threatening way.”

Biden responded by reminding Putin that “it’s impossible to win” a nuclear war.

Despite repeated warnings, Ukrainian President Volodymyr Zelensky dismissed the idea that Putin would actually invade, even after Vice President Kamala Harris told him during a February 2022 meeting at the Munich Security Conference that an invasion was imminent.

Harris told Zelensky he needed to “start thinking about things like having a succession plan in place to run the country if you are captured or killed or cannot govern.” After the meeting, Woodward writes, Harris said she was worried it might be the last time they ever saw him.

‘The most hair-raising moment of the whole war’

One of the most dramatic scenes in “War” reveals just how alarmed Biden and his national security team became over the prospect of Putin using nuclear weapons.

By September 2022, US intelligence reports deemed “exquisite” revealed a “deeply unnerving assessment” of Putin — that he was so desperate about battlefield losses that he might use tactical nuclear weapons in Ukraine.

Based on the alarming new intelligence reports, the White House believed there was a 50% chance Russia would use a tactical nuclear weapon — a striking assessment that had skyrocketed up from 5% and then 10%, Woodward reports.

“On all channels, get on the line with the Russians,” Biden instructed his national security adviser, Jake Sullivan. “Tell them what we will do in response,” he said, according to Woodward.

The book recounts a tense phone call between Defense Secretary Lloyd Austin and his Russian counterpart in October 2022.

“If you did this, all the restraints that we have been operating under in Ukraine would be reconsidered,” Austin said to Defense Minister Sergei Shoigu, according to Woodward. “This would isolate Russia on the world stage to a degree you Russians cannot fully appreciate.”

“I don’t take kindly to being threatened,” Shoigu responded.

“Mr. Minister,” Austin said, according to Woodward, “I am the leader of the most powerful military in the history of the world. I don’t make threats.”

Two days later, the Russians requested another call. This time, the Russian defense minister dramatically claimed the Ukrainians were planning to use a “dirty bomb” — a false story the US believed the Kremlin was pushing as a pretext to deploy a nuclear weapon.

“We don’t believe you,” Austin said firmly in response, according to Woodward. “We don’t see any indications of this, and the world will see through this.”

“Don’t do it,” he said to Shoigu.

“I understand,” Shoigu replied.

“It was probably the most hair-raising moment of the whole war,” Colin Kahl, a senior Pentagon official, later said of the episode.

kalvis kirjutas: ↑13 Okt, 2024 7:09 Ise tootes ei sea keegi kasutuspiiranguid.
Ise tootes on võimalik tootmisprotsessi riigil sekkuda ja optimeerida kulusi. JAH, käpardlikul juhtumil võib vastupidi ka juhtuda - on kordades kallim kui osta sama asi turult.

Tegelikult tasuks U. tõsiselt relvastuse tootmistehastel teha Läänega ühisettevõtteid. Mõlemad panustavad aktsiakapitali - U. põhiliselt siis tööjõu, tehase hoonete ja energiakandjaga, kui saab ka toormega (metall jne.). Lääne pool oskusteabe (relva tootmise litsents + kõik muu), tootmisseadme ja finantsidega (laen). Toodang läheb sõja ajal riigile, kusjuures U. riik maksab vaid maksimumis omahinna kui sedagi. Kuid iga müüdud toodang läheb siiski kirja letihinnaga. Peale sõda maksab U. Riik maksmata jäänud summad pikaajalise laenuga välja (vabalt võib ka 40 aastat olla). una tõenäoliselt on toode hea (tank, õhutõrje rakett või kasvõi kakuke) siis saab täiendavalt seda edukalt müüa teistelegi ja kõik on happy.

Mu arvates võiks isegi Eesti Riik just selle mudeliga U. relvaabi anda...