Japanese police have prepared a massive security plan to protect Tokyo summit delegates against dangers ranging from assassination attempts to assault by robot airplanes carrying explosives.

In the most elaborate security precautions ever staged here, police will put more than 26,000 armed officers on the streets of Tokyo to protect heads of state and other officials meeting here on June 28 and 29.

The economic summit meeting immediately follows the state visit of President Carter and the security preparations for both events are expected to cost nearly $2 million for police manpower alone.

Special bullet-proofed limousines have been bought for the seven nation's leaders. A large section of central Tokyo will be marked off limits to unauthorized persons. A special woman's squad, whose members are trained in one of Japan's martial arts, has been created to guard Britain's new prime minister, Margaret Thatcher, Mrs. Carter and her daughter Amy, and Canada's new foreign minister, Flora MacDonald.

Tokyo's jittery police department is expecting trouble from both leftist and rightist groups but acknowledges it has little solid information on dangers to protect against. Its spokesmen cite the possibilities of kidnapings, armed assaults, bombings, riots and demonstrations and police already have begun raiding offices of the more militant factions.

One leftist faction's newspaper has publicly called on adherents to "crush" the summit of Western capitalist countries and Japan and the recent robbery at a weapons store is believed the work of one urban guerrilla organization.

In addition, Japanese authorities as far away as Manila and Bangkok have been alerted to expect hijacking or kidnaping attempts by the Japanese Red Army, a small terrorist faction that usually operates out of Middle Eastern countries against Japanese targets.

Tokyo's new Otani Hotel will become a fortified castle, its 2,000-plus rooms closed to all but official summit guests. The visitors will travel by bullet-proof car through empty, barricaded streets the few hundred years to reach the government guest house, a palatial estate, where the summit meetings will be held.

Since the guest house will be barred to all except authorized visitors, police theorize that a likely weapon of attack will be the miniature, remote-controlled airplanes widely popular as toys in Japan. Loaded with explosives, they could be used as artillery against the building, they point out.

Although officials refused to discuss how they would counter such a flying attack, it was understood that a sophisitcated electronic device is being installed to deflect any small plane.

The police have been especially nervous about a report that they might have to protect Carter on a morning jog around the Imperial Palace in central Tokyo. They would prefer that he and other leaders remain indoors as much as possible.

The U.S. Embassy recently denied published reports that Carter planned to jog around the palace ground, a favorite running path for joggers.

"If he starts to run, we will protect him," said one police official. "But I can tell you that from the standpoint of security its preferable that he not run."

The basic police strategy for coping with assaults from any quarter is simple: smother it with large numbers of police, a technique regularly used here to handle Tokyo's frequent demonstrations.

He wryly referred to it as a "#sea of people" strategy, with waves of uniformed officers available to sweep the streets of protesters. He also said the actual number of police involved would be considerably more than the 26,000 figure revealed publicly.

One report, which police refuse to discuss, has it that authorities have developed a new light-weight bullet-proof overcoat to protect the statesmen from armed assassination attempts. According to one Japanese newspaper account, a guard would carry the grey coat on his rounds and fling it over the target if an attack appeared imminent.