Using full GPS-aided INS guidance, the accuracy of JDAM is officially quoted as 13 m (43 ft), but real figures are reportedly slightly better, around 10 m (33 ft). When GPS is unavailable (e.g. because of jamming), accuracy in INS-only mode drops to 30 m (100 ft) CEP, but that's still good enough for many purposes, and therefore GPS-jamming is far from disabling JDAM bombs.
В википедии интересная байка про JDAM и Афганистан: чуть не попали бомбой по Карзаю, потому что американский спецназовец во время боя поменял батарейки в жипиэске, и устройство сбросилось на настройки по умолчанию, и начало выдавать свои координаты, а не координаты желаемого места приземления бомбы. Эти координаты передали на самолет (B52 в роли close air support(!)). Сама бомба сработала как надо, и "попала прямо в эпицентр" (с).
Despite their precision, JDAM employment is not without risk. On December 5, 2001, a JDAM dropped by a B-52 in Afghanistan nearly killed Hamid Karzai, now the country's president, while he was leading anti-Taliban forces near Sayd Alim Kalay alongside a US Army Special Forces (SF) team. A large force of Taliban had engaged the combined force of Karzai's men and their American SF, nearly overwhelming them. The SF commander requested Close Air Support (CAS) to strike the Taliban positions in an effort to stop their advance. A JDAM was launched to fulfill the CAS request, but instead of striking the Taliban positions, it struck the Afghan/American position. The subsequent investigation of the incident determined that the terminal attack controller attached to the Special Forces team had changed the battery in the GPS receiver at some point during the battle, thereby causing the device to return to "default" and "display its own coordinates." As a result, the improper target coordinates were relayed to the delivery aircraft, and the bomb targeted the Afghani and American position, rather than the Taliban forces.[9] This incident resulted in three American soldiers and five allied Afghans were killed, with over forty others injured.
